Retrieving all the keys in a nested json in java

Retrieving all the keys in a nested json in java - java

This is the program i wrote:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package javaapplication1;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.StringTokenizer;
import net.sf.json.JSONException;
import net.sf.json.JSONObject;
/**
*
* #author 311001
*/
public class NewClass {
public static void main(String args[]) {
JSONObject parentData = new JSONObject();
JSONObject childData = new JSONObject();
try {
parentData.put("command", "login");
parentData.put("uid", "123123123");
childData.put("uid", "007");
childData.put("username", "sup");
childData.put("password", "bros");
parentData.put("params", childData);
System.out.println(parentData);
Map<String, String> map = new HashMap<>();
Iterator<?> iter = parentData.keys();
while (iter.hasNext()) {
String key = (String) iter.next();
String value = parentData.getString(key);
map.put(key, value);
}
for (Entry<String, String> entry : map.entrySet()) {
System.out.println("key > " + entry.getKey() + " : value = " + entry.getValue());
}
String testData = map.get("params.uid");
System.out.println(testData);
System.out.println("Tokenizing json");
String resultStr = parentData.toString();
System.out.println("String tokens ");
StringTokenizer st = new StringTokenizer(resultStr);
System.out.println(st.countTokens());
while (st.hasMoreTokens()) {
System.out.println(st.nextToken());
}
String testDat="abc :: result";
StringTokenizer simpleString = new StringTokenizer(testDat);
System.out.println("Tokenizing simple string");
System.out.println(simpleString.countTokens());
while (simpleString.hasMoreTokens()) {
System.out.println(simpleString.nextToken());
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
the output i got:
run:
{"command":"login","uid":"123123123","params":{"uid":"007","username":"sup","password":"bros"}}
key > uid : value = 123123123
key > command : value = login
key > params : value = {"uid":"007","username":"sup","password":"bros"}
null
Tokenizing json
String tokens
1
{"command":"login","uid":"123123123","params":{"uid":"007","username":"sup","password":"bros"}}
Tokenizing simple string
3
abc
::
result
BUILD SUCCESSFUL (total time: 0 seconds)
How can I recieve all the keys in my json object. In case I tokenize why do i get only one string token while for a simple string am getting the correct output 3 tokens.

You can recursively traverse your JsonObject to get all keys.
heres the pseudocode
findKeys(JsonObject obj,List keys){
List<String>keysFromObj=obj.keys();
keys.addAll(keysFromObj);
for(String key:keysFromObj){
if(obj.get(key).getClass()==JSONObject.class){
findKeys(obj.get(key),keys);
}
}
}
So suppose if your object is {"a":1,"b":{"c":"hello","d":4.0}}
the above function should give you ["a","b","c","d"]
But if you want only ["a","c","d"] as your output,you can write-
findKeys(JsonObject obj,List keys){
List<String>keysFromObj=obj.keys();
for(String key:keysFromObj){
if(obj.get(key).getClass()==JSONObject.class){
findKeys(obj.get(key),keys);
}else{
keys.add(key);
}
}
}

I am late to the party, but I am adding here my solution:
Input:
{
"glossary": {
"title": "example glossary",
"GlossDiv": {
"title": "S",
"GlossList": {
"GlossEntry": {
"ID": "SGML",
"SortAs": "SGML",
"GlossTerm": "Standard Generalized Markup Language",
"Acronym": "SGML",
"Abbrev": "ISO 8879:1986",
"GlossDef": {
"para": "A meta-markup language, used to create markup languages such as DocBook.",
"GlossSeeAlso": ["GML", "XML"]
},
"GlossSee": "markup"
}
}
}
}
}
Retrieve all unique keys:
public static void findAllKeys(Object object, Set<String> finalKeys) {
if (object instanceof JSONObject) {
JSONObject jsonObject = (JSONObject) object;
jsonObject.keySet().forEach(childKey -> {
finalKeys.add(childKey);
findAllKeys(jsonObject.get(childKey), finalKeys);
});
} else if (object instanceof JSONArray) {
JSONArray jsonArray = (JSONArray) object;
IntStream.range(0, jsonArray.length())
.mapToObj(jsonArray::get)
.forEach(o -> findAllKeys(o, finalKeys));
}
}
Usage:
Set<String> finalKeys = new HashSet<>();
findAllKeys(new JSONObject(str), finalKeys);
System.out.println(finalKeys);
Output:
[
GlossEntry,
GlossSee,
SortAs,
GlossList,
title,
GlossDiv,
glossary,
GlossTerm,
GlossDef,
para,
GlossSeeAlso,
ID,
Acronym,
Abbrev
]
Retrieve all unique "full path" keys:
public void findAllKeys(Object object, String key, Set<String> finalKeys) {
if (object instanceof JSONObject) {
JSONObject jsonObject = (JSONObject) object;
jsonObject.keySet().forEach(childKey -> {
findAllKeys(jsonObject.get(childKey), key != null ? key + "." + childKey : childKey, finalKeys);
});
} else if (object instanceof JSONArray) {
JSONArray jsonArray = (JSONArray) object;
finalKeys.add(key);
IntStream.range(0, jsonArray.length())
.mapToObj(jsonArray::get)
.forEach(jsonObject -> findAllKeys(jsonObject, key, finalKeys));
}
else{
finalKeys.add(key);
}
}
Usage:
Set<String> finalKeys = new HashSet<>();
findAllKeys(new JSONObject(jsonStr), null, finalKeys);
System.out.println(finalKeys);
Output:
[
glossary.GlossDiv.GlossList.GlossEntry.ID,
glossary.title,
glossary.GlossDiv.GlossList.GlossEntry.GlossSee,
glossary.GlossDiv.GlossList.GlossEntry.GlossTerm,
glossary.GlossDiv.GlossList.GlossEntry.Acronym,
glossary.GlossDiv.GlossList.GlossEntry.Abbrev,
glossary.GlossDiv.GlossList.GlossEntry.GlossDef.para,
glossary.GlossDiv.GlossList.GlossEntry.SortAs,
glossary.GlossDiv.GlossList.GlossEntry.GlossDef.GlossSeeAlso,
glossary.GlossDiv.title
]

Here is one implementation using org.json not org.json.simple
It finds all unique values of a json with the Key:value combination using java.
Input json:
{
d: {
results: [{
__metadata: {
uri:https://google.com,
type: User
},
userId: jmarthens1,
businessPhone: null,
salaryProrating: null,
empId: 2023,
lastModifiedDateTime: Date(1458308558000 + 0000),
finalJobRole: null,
username: jmarthens,
married: false,
futureLeader: null,
salary: 79000.0,
jobRole: Program Manager,
Professional Services,
nickname: null,
salaryLocal: null
}]
}
}
Result:
empId-2023
lastModifiedDateTime-Date(1458308558000+0000)
salary-79000.0
userId-jmarthens1
jobRole-Program Manager, Professional Services
type-User
uri-https://google.com
username-jmarthens
Code:
package test;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class TestClass {
private static StringBuilder strOut = new StringBuilder();
public static void main(String[] args) {
try {
String json = "{\"d\" : {\"results\" : [{\"__metadata\" : {\"uri\" : \"https://apisalesdemo8.successfactors.com:443/odata/v2/User('jmarthens1')\","
+ " \"type\" : \"SFOData.User\"}, \"userId\" : \"jmarthens1\", \"businessPhone\" : null, \"salaryProrating\" : null, \"empId\" : \"2023\", "
+ "\"lastModifiedDateTime\" : \"Date(1458308558000+0000)\", \"finalJobRole\" : null, \"username\" : \"jmarthens\", \"married\" : false, "
+ "\"futureLeader\" : null, \"salary\" : \"79000.0\", \"jobRole\" : \"Program Manager, Professional Services\", \"nickname\" : null, \"salaryLocal\" : null}]}}";
JSONObject inputJson = new JSONObject(json);
List<String> lst = new ArrayList<String>();
lst = findKeysOfJsonObject(inputJson, lst);
try (BufferedWriter writer = new BufferedWriter(new FileWriter("C:\\temp\\temp.txt"))) {
writer.write(strOut.toString());
}
} catch (JSONException | IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private static List<String> findKeysOfJsonArray(JSONArray jsonIn, List<String> keys) {
List<String> keysFromArr = new ArrayList<>();
if (jsonIn != null && jsonIn.length() != 0) {
for (int i = 0; i < jsonIn.length(); i++) {
JSONObject jsonObjIn = jsonIn.getJSONObject(i);
keysFromArr = findKeysOfJsonObject(jsonObjIn, keys);
}
}
return keysFromArr;
}
private static List<String> findKeysOfJsonObject(JSONObject jsonIn, List<String> keys) {
Iterator<String> itr = jsonIn.keys();
List<String> keysFromObj = makeList(itr);
keys.addAll(keysFromObj);
itr = jsonIn.keys();
while (itr.hasNext()) {
String itrStr = itr.next();
// System.out.println("out " + itrStr);
JSONObject jsout = null;
JSONArray jsArr = null;
if (jsonIn.get(itrStr).getClass() == JSONObject.class) {
jsout = jsonIn.getJSONObject(itrStr);
findKeysOfJsonObject(jsout, keys);
} else if (jsonIn.get(itrStr).getClass() == JSONArray.class) {
jsArr = jsonIn.getJSONArray(itrStr);
keys.addAll(findKeysOfJsonArray(jsArr, keys));
} else if (jsonIn.get(itrStr).getClass() == String.class) {
System.out.println(itrStr + "-" + jsonIn.get(itrStr));
strOut.append(itrStr + "," + jsonIn.get(itrStr));
strOut.append(System.lineSeparator());
}
}
return keys;
}
public static List<String> makeList(Iterator<String> iter) {
List<String> list = new ArrayList<String>();
while (iter.hasNext()) {
list.add(iter.next());
}
return list;
}
}

static Set<String> finalListOfKeys = new LinkedHashSet<String>();
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("Absolute path of json file"));
JSONObject jsonObject = (JSONObject) obj;
Set<String> jsonKeys = jsonObject.keySet();
for (String key : jsonKeys) {
Object val = jsonObject.get(key);
if (val instanceof JSONArray) {
JSONArray array = (JSONArray) val;
jsonArray(array, key);
} else if (val instanceof JSONObject) {
JSONObject jsonOb = (JSONObject) val;
jsonObj(jsonOb, key);
} else {
finalListOfKeys.add(key);
System.out.println("Key is : " + key);
}
}
System.out.println("Final List : " + finalListOfKeys);
} catch (Exception e) {
e.printStackTrace();
}
}
public static void jsonObj(JSONObject object, String key2) {
Set<String> innerKeys = object.keySet();
System.out.println("Inner Keys : " + innerKeys);
for (String key : innerKeys) {
System.out.println("Key : " + key);
Object val = object.get(key);
if (val instanceof JSONArray) {
JSONArray array = (JSONArray) val;
jsonArray(array, key2 + "->" + key);
} else if (val instanceof JSONObject) {
JSONObject jsonOb = (JSONObject) val;
jsonObj(jsonOb, key2 + "->" + key);
} else {
finalListOfKeys.add(key2 + "->" + key);
System.out.println("Key is : " + key2 + "->" + key);
}
}
}
public static void jsonArray(JSONArray array, String key) {
if (array.size() == 0) {
finalListOfKeys.add(key);
} else {
for (int i = 0; i < array.size(); i++) {
Object jObject = array.get(i);
if (jObject instanceof JSONObject) {
JSONObject job = (JSONObject) jObject;
System.out.println(job);
jsonObj(job, key);
}
}
}
}

Related

Dot notation to JSON (including arrays)

I want to convert dot notated string to a JSONObject but include arrays too, for example: I want to set first.second[0].third[0].fourth to some string. So, JSON must be:
{
"first": {
"second": [
{
"third": [
"fourth": "some string"
]
}
]
}
}
I found this method then edited and it turned out something like this:
private void expand(Object parent, String key, String value) {
if (key == null) return;
if (!key.contains(".") && !key.contains("[")) {
if (parent instanceof JSONObject) {
((JSONObject) parent).put(key, value);
} else {
((JSONArray) parent).put(value);
}
return;
}
String innerKey = key.substring(0, key.contains(".") ? key.indexOf(".") : key.length());
String formattedInnerKey = innerKey.contains("[") ? innerKey.substring(0, innerKey.indexOf("[")) : innerKey;
String remaining = key.contains(".") ? key.substring(key.indexOf(".") + 1) : key.contains("]") ? key.substring(key.indexOf("]") + 1) : null;
if (parent instanceof JSONObject) {
JSONObject jsonObject = (JSONObject) parent;
if (jsonObject.has(formattedInnerKey)) {
expand(jsonObject.get(formattedInnerKey), remaining, value);
return;
}
} else {
JSONArray jsonArray = (JSONArray) parent;
Matcher matcher = Pattern.compile("(?<=\\[)([^\\]]+)(?=\\])").matcher(innerKey);
Preconditions.checkState(matcher.find(), String.format("Matcher couldn't find a index number in \"%s\"", innerKey));
int index = Integer.parseInt(matcher.group());
System.out.print(index + " - ");
if (!jsonArray.isNull(index)) {
System.out.print(jsonArray.get(index));
expand(jsonArray.get(index), remaining, value);
return;
}
}
Object obj = innerKey.contains("[") ? new JSONArray() : new JSONObject();
if (parent instanceof JSONObject) {
((JSONObject) parent).put(formattedInnerKey, obj);
} else {
JSONObject base = new JSONObject();
base.put(formattedInnerKey, obj);
Matcher matcher = Pattern.compile("(?<=\\[)([^\\]]+)(?=\\])").matcher(innerKey);
Preconditions.checkState(matcher.find(), String.format("Matcher couldn't find a index number in \"%s\"", innerKey));
int index = Integer.parseInt(matcher.group());
((JSONArray) parent).put(index, base);
}
expand(obj, remaining, value);
}
This method -kinda- works but the problem is that it adds elements to the array instead of putting. I want to be able to put the object to an index in that array. How can I fix this?

Here's the solution:
public void expand(Object parent, String key, Object value) {
JSONElement element = new JSONElement(parent);
if (!key.contains(".")) { // End
element.put(key, value);
return;
}
String innerKey = key.substring(0, key.indexOf("."));
String remaining = key.substring(key.indexOf(".") + 1);
if (element.has(innerKey)) {
expand(element.get(innerKey), remaining, value);
return;
}
Object object = element.newInstance();
Object put = element.put(innerKey, object);
expand(put, remaining, value);
}
JSONElement class:
import com.google.common.base.Preconditions;
import org.json.JSONArray;
import org.json.JSONObject;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class JSONElement {
private static final Pattern pattern = Pattern.compile("(?<=\\[)([^]]+)(?=])");
private final Object base;
public JSONElement(Object base) {
Preconditions.checkNotNull(base, "base");
Preconditions.checkState(base instanceof JSONObject || base instanceof JSONArray, "base must be a JSONObject or JSONArray instead of " + base.getClass().getSimpleName());
this.base = base;
}
public Object put(Object key, Object value) {
String keyAsString = String.valueOf(key);
if (base instanceof JSONObject) {
if (keyAsString.contains("[")) {
String formatKey = keyAsString.contains("[") ? keyAsString.substring(0, keyAsString.indexOf("[")) : keyAsString;
JSONArray array = ((JSONObject) base).has(formatKey) ? ((JSONObject) base).getJSONArray(formatKey) : new JSONArray();
int index = getIndex(keyAsString);
array.put(index, value);
((JSONObject) base).put(formatKey, array);
return ((JSONArray) ((JSONObject) base).get(formatKey)).get(index);
}
((JSONObject) base).put(keyAsString, value);
return ((JSONObject) base).get(keyAsString);
}
int index = getIndex(keyAsString);
((JSONArray) base).put(index, value);
return ((JSONArray) base).get(index);
}
public boolean has(Object key) {
String keyAsString = String.valueOf(key);
if (base instanceof JSONObject) {
JSONObject object = (JSONObject) base;
String formatKey = formatKey(keyAsString);
if (keyAsString.contains("["))
return object.has(formatKey) && !object.getJSONArray(formatKey).isNull(getIndex(keyAsString));
return object.has(formatKey);
}
return !((JSONArray) base).isNull(getIndex(keyAsString));
}
public Object get(Object key) {
String keyAsString = String.valueOf(key);
if (base instanceof JSONObject) {
JSONObject object = (JSONObject) base;
String formatKey = formatKey(keyAsString);
if (keyAsString.contains("["))
return object.getJSONArray(formatKey).get(getIndex(keyAsString));
return object.get(formatKey);
}
return ((JSONArray) base).get(getIndex(keyAsString));
}
public Object newInstance() {
return base instanceof JSONObject ? new JSONObject() : new JSONArray();
}
private int getIndex(String key) {
Matcher matcher = pattern.matcher(key);
Preconditions.checkState(matcher.find(), String.format("Matcher couldn't find an index number in \"%s\"", key));
return Integer.parseInt(matcher.group());
}
private String formatKey(String key) {
return key.contains("[") ? key.substring(0, key.indexOf("[")) : key;
}
}
Usage:
JSONObject jsonObject = new JSONObject();
expand(jsonObject, "first.second[0].third[0].fourth", "some string");
System.out.println(jsonObject.toString()); // Prints: {"first":{"second":[{"third":[{"fourth":"some string"}]}]}}

How to create a Java method to parse a big JSON file

I am trying to parse the content of JSON file text.json by using Jackson library.
What I want is to make a java method to get all keys and values of it, but so far in my code I get only the first key and the first value of the JSON file.
The code snippet I used as guidance to make my own Java class is the following:
public void parse(String json) {
JsonFactory factory = new JsonFactory();
ObjectMapper mapper = new ObjectMapper(factory);
JsonNode rootNode = mapper.readTree(json);
Iterator<Map.Entry<String,JsonNode>> fieldsIterator = rootNode.fields();
while (fieldsIterator.hasNext()) {
Map.Entry<String,JsonNode> field = fieldsIterator.next();
System.out.println("Key: " + field.getKey() + "\tValue:" + field.getValue());
}
}
And my Java class that I created is shown below:
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.JsonNode;
import org.codehaus.jackson.JsonParser;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
public class JacksonStreamExample {
public static void main(String[] args) {
try {
//Create a JsonFactory instance
JsonFactory factory = new JsonFactory();
//Create a JsonParser instance to read from file c:\\text.json
JsonParser jParser = factory.createJsonParser(new File("c:\\text.json"));
/*Create an ObjectMapper instance to provide a pointer
* to root node of the tree after reading the JSON
*/
ObjectMapper mapper = new ObjectMapper(factory);
//Create tree from JSON
JsonNode rootNode = mapper.readTree(jParser);
Iterator<Map.Entry<String,JsonNode>> fieldsIterator = rootNode.getFields();
while (fieldsIterator.hasNext()) {
Map.Entry<String,JsonNode> field = fieldsIterator.next();
System.out.println("Key: " + field.getKey() + "\tValue:" + field.getValue());
}
jParser.close();
} catch (JsonGenerationException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
My Eclipse output is the following which creates only 1 pair(key-value):
Key: cells Value:[{"type":"basic.Circle","size":{"width":90,"height":54},"position":{"x":-80,"y":200},"angle":0,"id":"cae4c219-c2cd-4a4b-b50c-0f269963ca24","embeds":"","z":1,"wi_name":"START","wi_displayName":"START","wi_description":"","wi_join":"<None>","wi_split":"<None>","wi_performingRole":"<None>","wi_expected_activity_time":null,"wi_expected_user_time":null,"wi_maximum_activity_time":null,"wi_initial_delay":null,"wi_time_unit":"Seconds","wi_required_transitions_for_AND_JOIN":null,"wi_custom_page":"","attrs":{"circle":{"fill":"#000000","width":50,"height":30,"stroke-width":1,"stroke-dasharray":"0"},"text":{"font-size":10,"text":"START","fill":"#ffffff","font-family":"Arial","stroke":"#000000","stroke-width":0,"font-weight":400}}},{"type":"basic.Circle","size":{"width":90,"height":54},"position":{"x":210,"y":200},"angle":0,"id":"d23133e0-e516-4f72-8127-292545d3d479","embeds":"","z":2,"wi_name":"END","wi_displayName":"END","wi_description":"","wi_join":"<None>","wi_split":"<None>","wi_performingRole":"<None>","wi_expected_activity_time":null,"wi_expected_user_time":null,"wi_maximum_activity_time":null,"wi_initial_delay":null,"wi_time_unit":"Seconds","wi_required_transitions_for_AND_JOIN":null,"wi_custom_page":"","attrs":{"circle":{"fill":"#000000","width":50,"height":30,"stroke-width":1,"stroke-dasharray":"0"},"text":{"font-size":10,"text":"END","fill":"#ffffff","font-family":"Arial","stroke":"#000000","stroke-width":0,"font-weight":400}}},{"type":"basic.Rect","position":{"x":-80,"y":370},"size":{"width":90,"height":54},"angle":0,"id":"a53898a5-c018-45c4-bd3f-4ea4d69f58ed","embeds":"","z":3,"wi_name":"ACTIVITY_1","wi_displayName":"ACTIVITY 1","wi_description":"","wi_join":"<None>","wi_split":"<None>","wi_performingRole":"<None>","wi_expected_activity_time":null,"wi_expected_user_time":null,"wi_maximum_activity_time":null,"wi_initial_delay":null,"wi_time_unit":"Seconds","wi_required_transitions_for_AND_JOIN":null,"wi_custom_page":"","attrs":{"rect":{"width":50,"height":30,"rx":2,"ry":2,"stroke-width":1,"stroke-dasharray":"0"},"text":{"text":"Activity","font-size":10,"font-family":"Arial","stroke":"#000000","stroke-width":0,"font-weight":400}}},{"type":"basic.Rect","position":{"x":220,"y":370},"size":{"width":90,"height":54},"angle":0,"id":"e2bd21f2-508d-44b9-9f68-e374d4fa87ea","embeds":"","z":4,"wi_name":"ACTIVITY_2","wi_displayName":"ACTIVITY 2","wi_description":"","wi_join":"<None>","wi_split":"<None>","wi_performingRole":"<None>","wi_expected_activity_time":null,"wi_expected_user_time":null,"wi_maximum_activity_time":null,"wi_initial_delay":null,"wi_time_unit":"Seconds","wi_required_transitions_for_AND_JOIN":null,"wi_custom_page":"","attrs":{"rect":{"width":50,"height":30,"rx":2,"ry":2,"stroke-width":1,"stroke-dasharray":"0"},"text":{"text":"Workitem","font-size":10,"font-family":"Arial","stroke":"#000000","stroke-width":0,"font-weight":400}}},{"type":"link","source":{"id":"cae4c219-c2cd-4a4b-b50c-0f269963ca24"},"target":{"id":"d23133e0-e516-4f72-8127-292545d3d479"},"router":{"name":"manhattan"},"labels":[{"position":0.5,"attrs":{"text":{"text":"Name"}}}],"id":"60ee7ff7-3a3b-487d-b581-49027e7bebe4","embeds":"","z":5,"attrs":{".marker-source":{"d":"M 10 0 L 0 5 L 10 10 z","transform":"scale(0.001)"},".marker-target":{"d":"M 10 0 L 0 5 L 10 10 z"},".connection":{"stroke":"black"}}},{"type":"link","source":{"id":"a53898a5-c018-45c4-bd3f-4ea4d69f58ed"},"target":{"id":"e2bd21f2-508d-44b9-9f68-e374d4fa87ea"},"router":{"name":"manhattan"},"labels":[{"position":0.5,"attrs":{"text":{"text":"Name"}}}],"id":"cea0d1c2-2c18-4bd7-ba35-d94918c6fc9b","embeds":"","z":6,"attrs":{".marker-source":{"d":"M 10 0 L 0 5 L 10 10 z","transform":"scale(0.001)"},".marker-target":{"d":"M 10 0 L 0 5 L 10 10 z"},".connection":{"stroke":"black"}}}]
I just need to make a method to put this code inside to get all key-value pairs:
//Create a JsonFactory instance
JsonFactory factory = new JsonFactory();
//Create a JsonParser instance to read from file c:\\text.json
JsonParser jParser = factory.createJsonParser(new File("c:\\text.json"));
/*Create an ObjectMapper instance to provide a pointer
*to root node of the tree after reading the JSON
*/
ObjectMapper mapper = new ObjectMapper(factory);
//Create tree from JSON
JsonNode rootNode = mapper.readTree(jParser);
Iterator<Map.Entry<String,JsonNode>> fieldsIterator = rootNode.getFields();
while (fieldsIterator.hasNext()) {
Map.Entry<String,JsonNode> field = fieldsIterator.next();
System.out.println("Key: " + field.getKey() + "\tValue:" + field.getValue());
}
How will I do it please?

You should use Jackson2 instead of Jackson1. As the error message specifies, Jackson1's JsonNode indeed does not have this fields() method, while Jackson2's version does.
In Jackson1, you would have to do something like this:
Iterator<String> fieldNameIterator = rootNode.getFieldNames();
while (fieldNameIterator.hasNext()) {
String fieldName = fieldNameIterator.next();
JsonNode fieldValue = rootNode.getFieldValue(fieldName);
System.out.println("Key: " + fieldName + "\tValue:" + fieldValue);
}

I solved my problem by changing JSON library.
I used json-simple-1.1.1
My final code that worked is the following:
package jsontoxml;
import java.io.*;
import org.json.simple.parser.JSONParser;
import org.json.simple.*;
import java.util.*;
public class JacksonStreamExample {
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("text.json"));
JSONObject jsonObject = (JSONObject) obj;
JSONArray cells = (JSONArray) jsonObject.get("cells");
Iterator<JSONObject> iterator = cells.iterator();
while(iterator.hasNext()){
System.out.println(iterator.next());
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

Now that you have modified the question and json, here is the solution you're looking for:
public static void main(String[] args) {
try {
Map source = (new ObjectMapper()).readValue(new File(
"C:\\json.txt"), Map.class);
Map<String, Object> result = new LinkedHashMap<>();
buildFlattenedMap(result, source, null);
for (String s : result.keySet()) {
System.out.println(s);
}
} catch (Exception e) {
e.printStackTrace();
}
}
private static void buildFlattenedMap(Map<String, Object> result,
Map<String, Object> source, String path) {
for (Map.Entry<String, Object> entry : source.entrySet()) {
String key = entry.getKey();
if (hasText(path)) {
if (key.charAt(0) == '[') {
key = StringUtils.join(path, key);
} else {
key = StringUtils.join(path, '.', key);
}
}
Object value = entry.getValue();
if (value instanceof String) {
result.put(key, value);
} else if (value instanceof Map) {
// Need a compound key
#SuppressWarnings("unchecked")
Map<String, Object> map = (Map<String, Object>) value;
buildFlattenedMap(result, map, key);
} else if (value instanceof Collection) {
// Need a compound key
#SuppressWarnings("unchecked")
Collection<Object> collection = (Collection<Object>) value;
int count = 0;
for (Object object : collection) {
buildFlattenedMap(result, Collections.singletonMap("["
+ (count++) + "]", object), key);
}
} else {
result.put(key, value == null ? StringUtils.EMPTY : value);
}
}
}
private static boolean hasText(CharSequence str) {
if (StringUtils.isEmpty(str)) {
return false;
}
int strLen = str.length();
for (int i = 0; i < strLen; i++) {
if (!Character.isWhitespace(str.charAt(i))) {
return true;
}
}
return false;
}
FYI, buildFlattenedMap method is actually from spring framework which I had used recently for processing a similar stuff.
https://github.com/spring-projects/spring-framework/blob/master/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlProcessor.java

JSON PII data masking in Java

I would like to mask certain elements of JSON and print to logs. Masking can be either by substituting by dummy data or removing the key pair .Is there a utility to do the masking in Java ?
E.g.,
given JSON:
{
"key1":"value1",
"key2":"value2",
"key3":"value3",
}
mask key 2 alone and print JSON:
{
"key1":"value1",
"key2":"xxxxxx",
"key3":"value3",
}
or
{
"key1":"value1",
"key3":"value3",
}

input will be JSON object or array type in string format. Here the maskable keys only static otherwise input string will dynamic.
public final class MaskPIData {
/**
* Mask able keywords mentioned here. It should be in LOWER CASE.
*/
private static final Set<String> MASKABLE_KEYS = new HashSet<>(Arrays.asList(
"email",
"emails",
"phone",
"pin",
"password",
"phonenumber",
"moneys"));
private static final String MASKING_VALUE = "****";
private static final ObjectMapper OBJECTMAPPER = new ObjectMapper();
private MaskPIData() {
super();
}
private static boolean isValidSet(Set<String> set) {
return set != null && !set.isEmpty();
}
private static boolean isKnownPrimitiveWrapperModel(Object obj) {
return obj == null || obj instanceof String || obj instanceof Integer || obj instanceof Long
|| obj instanceof Double;
}
#SuppressWarnings("unchecked")
private static JSONObject maskingForJsonObject(Set<String> maskableKeys, JSONObject input) {
if (!isValidSet(maskableKeys) || input == null) {
return input;
}
Map<String, Object> inputMap = (Map<String, Object>) input;
Map<String, Object> caseInsensitiveInputMap = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
caseInsensitiveInputMap.putAll(inputMap);
for (Map.Entry<String, Object> entryPair : caseInsensitiveInputMap.entrySet()) {
if (entryPair.getValue() instanceof JSONArray) {
JSONArray jsonArr = (JSONArray) caseInsensitiveInputMap.get(entryPair.getKey());
maskingForArray(maskableKeys, entryPair.getKey(), jsonArr);
caseInsensitiveInputMap.put(entryPair.getKey(), jsonArr);
} else if (entryPair.getValue() instanceof JSONObject) {
JSONObject jsonObj = (JSONObject) caseInsensitiveInputMap.get(entryPair.getKey());
caseInsensitiveInputMap.put(entryPair.getKey(), maskingForJsonObject(maskableKeys, jsonObj));
} else if (entryPair.getKey() != null && maskableKeys.contains(entryPair.getKey().toLowerCase())) {
caseInsensitiveInputMap.put(entryPair.getKey(), MASKING_VALUE);
}
}
return OBJECTMAPPER.convertValue(caseInsensitiveInputMap, JSONObject.class);
}
#SuppressWarnings("unchecked")
private static JSONArray maskingForArray(Set<String> maskableKeys, String key,
JSONArray jsonArr) {
JSONArray toRet = jsonArr;
for (int idx = 0; idx < toRet.size(); idx++) {
Object obj = toRet.get(idx);
if (isKnownPrimitiveWrapperModel(obj)) {
if (key != null && maskableKeys.contains(key.toLowerCase())) {
toRet.remove(idx);
toRet.add(idx, MASKING_VALUE);
}
} else {
JSONObject jsonObjFromArray = (JSONObject) toRet.get(idx);
JSONObject maskedJsonObj = maskingForJsonObject(maskableKeys, jsonObjFromArray);
toRet.remove(idx);
toRet.add(idx, maskedJsonObj);
}
}
return toRet;
}
public static String doMask(String input) {
String maskedData = input;
if (maskedData != null && !maskedData.trim().isEmpty()) {
try {
if (new JSONParser().parse(maskedData) instanceof JSONObject) {
JSONObject maskedOutput = maskingForJsonObject(MASKABLE_KEYS,
(JSONObject) new JSONParser().parse(maskedData));
maskedData = OBJECTMAPPER.writeValueAsString(maskedOutput);
} else if (new JSONParser().parse(maskedData) instanceof JSONArray) {
JSONArray maskedOutput = maskingForArray(MASKABLE_KEYS, null, (JSONArray) new JSONParser().parse(maskedData));
maskedData = OBJECTMAPPER.writeValueAsString(maskedOutput);
}
} catch (Exception e) {
// to do - Error while masking data
}
}
return maskedData;
}
public static void main(String args[]) {
String input = "{\"item\":{\"test\":\"test\",\"phone\":\"993244\",\"email\":\"mail#mail.com\"}}";
System.out.println(doMask(input));
}

You could use jackson to convert json to map, process map and convert map back to json.
For example:
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.type.TypeReference;
public void mask() throws IOException {
String jsonString = "{\n" +
" \"key1\":\"value1\",\n" +
" \"key2\":\"value2\",\n" +
" \"key3\":\"value3\"\n" +
"}";
Map<String, Object> map;
// Convert json to map
ObjectMapper mapper = new ObjectMapper();
try {
TypeReference ref = new TypeReference<Map<String, Object>>() { };
map = mapper.readValue(jsonString, ref);
} catch (IOException e) {
System.out.print("cannot create Map from json" + e.getMessage());
throw e;
}
// Process map
if(map.containsKey("key2")) {
map.put("key2","xxxxxxxxx");
}
// Convert back map to json
String jsonResult = "";
try {
jsonResult = mapper.writeValueAsString(map);
} catch (IOException e) {
System.out.print("cannot create json from Map" + e.getMessage());
}
System.out.print(jsonResult);

Parsing JSON in Java without knowing JSON format

I am trying to parse JSON strings in Java and find the key-value pairs so that I can determine the approximate structure of the JSON object since object structure of JSON string is unknown.
For example, one execution may have a JSON string like this:
{"id" : 12345, "days" : [ "Monday", "Wednesday" ], "person" : { "firstName" : "David", "lastName" : "Menoyo" } }
And another like this:
{"url" : "http://someurl.com", "method" : "POST", "isauth" : false }
How would I cycle through the various JSON elements and determine the keys and their values? I looked at jackson-core's JsonParser. I see how I can grab the next "token" and determine what type of token it is (i.e., field name, value, array start, etc), but, I don't know how to grab the actual token's value.
For example:
public void parse(String json) {
try {
JsonFactory f = new JsonFactory();
JsonParser parser = f.createParser(json);
JsonToken token = parser.nextToken();
while (token != null) {
if (token.equals(JsonToken.START_ARRAY)) {
logger.debug("Start Array : " + token.toString());
} else if (token.equals(JsonToken.END_ARRAY)) {
logger.debug("End Array : " + token.toString());
} else if (token.equals(JsonToken.START_OBJECT)) {
logger.debug("Start Object : " + token.toString());
} else if (token.equals(JsonToken.END_OBJECT)) {
logger.debug("End Object : " + token.toString());
} else if (token.equals(JsonToken.FIELD_NAME)) {
logger.debug("Field Name : " + token.toString());
} else if (token.equals(JsonToken.VALUE_FALSE)) {
logger.debug("Value False : " + token.toString());
} else if (token.equals(JsonToken.VALUE_NULL)) {
logger.debug("Value Null : " + token.toString());
} else if (token.equals(JsonToken.VALUE_NUMBER_FLOAT)) {
logger.debug("Value Number Float : " + token.toString());
} else if (token.equals(JsonToken.VALUE_NUMBER_INT)) {
logger.debug("Value Number Int : " + token.toString());
} else if (token.equals(JsonToken.VALUE_STRING)) {
logger.debug("Value String : " + token.toString());
} else if (token.equals(JsonToken.VALUE_TRUE)) {
logger.debug("Value True : " + token.toString());
} else {
logger.debug("Something else : " + token.toString());
}
token = parser.nextToken();
}
} catch (Exception e) {
logger.error("", e);
}
}
Is there a class in jackson or some other library (gson or simple-json) that produces a tree, or allows one to cycle through the json elements and obtain the actual key names in addition to the values?

Take a look at Jacksons built-in tree model feature.
And your code will be:
public void parse(String json) {
JsonFactory factory = new JsonFactory();
ObjectMapper mapper = new ObjectMapper(factory);
JsonNode rootNode = mapper.readTree(json);
Iterator<Map.Entry<String,JsonNode>> fieldsIterator = rootNode.fields();
while (fieldsIterator.hasNext()) {
Map.Entry<String,JsonNode> field = fieldsIterator.next();
System.out.println("Key: " + field.getKey() + "\tValue:" + field.getValue());
}
}

If a different library is fine for you, you could try org.json:
JSONObject object = new JSONObject(myJSONString);
String[] keys = JSONObject.getNames(object);
for (String key : keys)
{
Object value = object.get(key);
// Determine type of value and do something with it...
}

Find the following code for Unknown Json Object parsing using Gson library.
public class JsonParsing {
static JsonParser parser = new JsonParser();
public static HashMap<String, Object> createHashMapFromJsonString(String json) {
JsonObject object = (JsonObject) parser.parse(json);
Set<Map.Entry<String, JsonElement>> set = object.entrySet();
Iterator<Map.Entry<String, JsonElement>> iterator = set.iterator();
HashMap<String, Object> map = new HashMap<String, Object>();
while (iterator.hasNext()) {
Map.Entry<String, JsonElement> entry = iterator.next();
String key = entry.getKey();
JsonElement value = entry.getValue();
if (null != value) {
if (!value.isJsonPrimitive()) {
if (value.isJsonObject()) {
map.put(key, createHashMapFromJsonString(value.toString()));
} else if (value.isJsonArray() && value.toString().contains(":")) {
List<HashMap<String, Object>> list = new ArrayList<>();
JsonArray array = value.getAsJsonArray();
if (null != array) {
for (JsonElement element : array) {
list.add(createHashMapFromJsonString(element.toString()));
}
map.put(key, list);
}
} else if (value.isJsonArray() && !value.toString().contains(":")) {
map.put(key, value.getAsJsonArray());
}
} else {
map.put(key, value.getAsString());
}
}
}
return map;
}
}

JSON of unknown format to HashMap
writing JSON And reading Json
public static JsonParser parser = new JsonParser();
public static void main(String args[]) {
writeJson("JsonFile.json");
readgson("JsonFile.json");
}
public static void readgson(String file) {
try {
System.out.println( "Reading JSON file from Java program" );
FileReader fileReader = new FileReader( file );
com.google.gson.JsonObject object = (JsonObject) parser.parse( fileReader );
Set <java.util.Map.Entry<String, com.google.gson.JsonElement>> keys = object.entrySet();
if ( keys.isEmpty() ) {
System.out.println( "Empty JSON Object" );
}else {
Map<String, Object> map = json_UnKnown_Format( keys );
System.out.println("Json 2 Map : "+map);
}
} catch (IOException ex) {
System.out.println("Input File Does not Exists.");
}
}
public static Map<String, Object> json_UnKnown_Format( Set <java.util.Map.Entry<String, com.google.gson.JsonElement>> keys ){
Map<String, Object> jsonMap = new HashMap<String, Object>();
for (Entry<String, JsonElement> entry : keys) {
String keyEntry = entry.getKey();
System.out.println(keyEntry + " : ");
JsonElement valuesEntry = entry.getValue();
if (valuesEntry.isJsonNull()) {
System.out.println(valuesEntry);
jsonMap.put(keyEntry, valuesEntry);
}else if (valuesEntry.isJsonPrimitive()) {
System.out.println("P - "+valuesEntry);
jsonMap.put(keyEntry, valuesEntry);
}else if (valuesEntry.isJsonArray()) {
JsonArray array = valuesEntry.getAsJsonArray();
List<Object> array2List = new ArrayList<Object>();
for (JsonElement jsonElements : array) {
System.out.println("A - "+jsonElements);
array2List.add(jsonElements);
}
jsonMap.put(keyEntry, array2List);
}else if (valuesEntry.isJsonObject()) {
com.google.gson.JsonObject obj = (JsonObject) parser.parse(valuesEntry.toString());
Set <java.util.Map.Entry<String, com.google.gson.JsonElement>> obj_key = obj.entrySet();
jsonMap.put(keyEntry, json_UnKnown_Format(obj_key));
}
}
return jsonMap;
}
#SuppressWarnings("unchecked")
public static void writeJson( String file ) {
JSONObject json = new JSONObject();
json.put("Key1", "Value");
json.put("Key2", 777); // Converts to "777"
json.put("Key3", null);
json.put("Key4", false);
JSONArray jsonArray = new JSONArray();
jsonArray.put("Array-Value1");
jsonArray.put(10);
jsonArray.put("Array-Value2");
json.put("Array : ", jsonArray); // "Array":["Array-Value1", 10,"Array-Value2"]
JSONObject jsonObj = new JSONObject();
jsonObj.put("Obj-Key1", 20);
jsonObj.put("Obj-Key2", "Value2");
jsonObj.put(4, "Value2"); // Converts to "4"
json.put("InnerObject", jsonObj);
JSONObject jsonObjArray = new JSONObject();
JSONArray objArray = new JSONArray();
objArray.put("Obj-Array1");
objArray.put(0, "Obj-Array3");
jsonObjArray.put("ObjectArray", objArray);
json.put("InnerObjectArray", jsonObjArray);
Map<String, Integer> sortedTree = new TreeMap<String, Integer>();
sortedTree.put("Sorted1", 10);
sortedTree.put("Sorted2", 103);
sortedTree.put("Sorted3", 14);
json.put("TreeMap", sortedTree);
try {
System.out.println("Writting JSON into file ...");
System.out.println(json);
FileWriter jsonFileWriter = new FileWriter(file);
jsonFileWriter.write(json.toJSONString());
jsonFileWriter.flush();
jsonFileWriter.close();
System.out.println("Done");
} catch (IOException e) {
e.printStackTrace();
}
}

Here is a sample I wrote shows how I parse a json and mess every number inside it:
public class JsonParser {
public static Object parseAndMess(Object object) throws IOException {
String json = JsonUtil.toJson(object);
JsonNode jsonNode = parseAndMess(json);
if(null != jsonNode)
return JsonUtil.toObject(jsonNode, object.getClass());
return null;
}
public static JsonNode parseAndMess(String json) throws IOException {
JsonNode rootNode = parse(json);
return mess(rootNode, new Random());
}
private static JsonNode parse(String json) throws IOException {
JsonFactory factory = new JsonFactory();
ObjectMapper mapper = new ObjectMapper(factory);
JsonNode rootNode = mapper.readTree(json);
return rootNode;
}
private static JsonNode mess(JsonNode rootNode, Random rand) throws IOException {
if (rootNode instanceof ObjectNode) {
Iterator<Map.Entry<String, JsonNode>> fieldsIterator = rootNode.fields();
while (fieldsIterator.hasNext()) {
Map.Entry<String, JsonNode> field = fieldsIterator.next();
replaceObjectNode((ObjectNode) rootNode, field, rand);
}
} else if (rootNode instanceof ArrayNode) {
ArrayNode arrayNode = ((ArrayNode) rootNode);
replaceArrayNode(arrayNode, rand);
}
return rootNode;
}
private static void replaceObjectNode(ObjectNode rootNode, Map.Entry<String, JsonNode> field, Random rand)
throws IOException {
JsonNode childNode = field.getValue();
if (childNode instanceof IntNode) {
(rootNode).put(field.getKey(), rand.nextInt(1000));
} else if (childNode instanceof LongNode) {
(rootNode).put(field.getKey(), rand.nextInt(1000000));
} else if (childNode instanceof FloatNode) {
(rootNode).put(field.getKey(), format(rand.nextFloat()));
} else if (childNode instanceof DoubleNode) {
(rootNode).put(field.getKey(), format(rand.nextFloat()));
} else {
mess(childNode, rand);
}
}
private static void replaceArrayNode(ArrayNode arrayNode, Random rand) throws IOException {
int arrayLength = arrayNode.size();
if(arrayLength == 0)
return;
if (arrayNode.get(0) instanceof IntNode) {
for (int i = 0; i < arrayLength; i++) {
arrayNode.set(i, new IntNode(rand.nextInt(10000)));
}
} else if (arrayNode.get(0) instanceof LongNode) {
arrayNode.removeAll();
for (int i = 0; i < arrayLength; i++) {
arrayNode.add(rand.nextInt(1000000));
}
} else if (arrayNode.get(0) instanceof FloatNode) {
arrayNode.removeAll();
for (int i = 0; i < arrayLength; i++) {
arrayNode.add(format(rand.nextFloat()));
}
} else if (arrayNode.get(0) instanceof DoubleNode) {
arrayNode.removeAll();
for (int i = 0; i < arrayLength; i++) {
arrayNode.add(format(rand.nextFloat()));
}
} else {
for (int i = 0; i < arrayLength; i++) {
mess(arrayNode.get(i), rand);
}
}
}
public static void print(JsonNode rootNode) throws IOException {
System.out.println(rootNode.toString());
}
private static double format(float a) {
return Math.round(a * 10000.0) / 100.0;
}
}

Would you be satisfied with a Map from Jackson?
ObjectMapper objectMapper = new ObjectMapper();
Map<String, Object> map = objectMapper.readValue(jsonString, new TypeReference<HashMap<String,Object>>(){});
Or maybe a JsonNode?
JsonNode jsonNode = objectMapper.readTree(String jsonString)

How to read json file into java with simple JSON library

I want to read this JSON file with java using json simple library.
My JSON file looks like this:
[
{
"name":"John",
"city":"Berlin",
"cars":[
"audi",
"bmw"
],
"job":"Teacher"
},
{
"name":"Mark",
"city":"Oslo",
"cars":[
"VW",
"Toyata"
],
"job":"Doctor"
}
]
This is the java code I wrote to read this file:
package javaapplication1;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
public class JavaApplication1 {
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("c:\\file.json"));
JSONObject jsonObject = (JSONObject) obj;
String name = (String) jsonObject.get("name");
System.out.println(name);
String city = (String) jsonObject.get("city");
System.out.println(city);
String job = (String) jsonObject.get("job");
System.out.println(job);
// loop array
JSONArray cars = (JSONArray) jsonObject.get("cars");
Iterator<String> iterator = cars.iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
}
But I get the following exception:
Exception in thread "main" java.lang.ClassCastException:
org.json.simple.JSONArray cannot be cast to org.json.simple.JSONObject
at javaapplication1.JavaApplication1.main(JavaApplication1.java:24)
Can somebody tell me what I am doing wrong? The whole file is a array and there are objects and another array (cars) in the whole array of the file. But i dont know how I can parse the whole array into a java array. I hope somebody can help me with a code line which I am missing in my code.
Thanks

The whole file is an array and there are objects and other arrays (e.g. cars) in the whole array of the file.
As you say, the outermost layer of your JSON blob is an array. Therefore, your parser will return a JSONArray. You can then get JSONObjects from the array ...
JSONArray a = (JSONArray) parser.parse(new FileReader("c:\\exer4-courses.json"));
for (Object o : a)
{
JSONObject person = (JSONObject) o;
String name = (String) person.get("name");
System.out.println(name);
String city = (String) person.get("city");
System.out.println(city);
String job = (String) person.get("job");
System.out.println(job);
JSONArray cars = (JSONArray) person.get("cars");
for (Object c : cars)
{
System.out.println(c+"");
}
}
For reference, see "Example 1" on the json-simple decoding example page.

You can use jackson library and simply use these 3 lines to convert your json file to Java Object.
ObjectMapper mapper = new ObjectMapper();
InputStream is = Test.class.getResourceAsStream("/test.json");
testObj = mapper.readValue(is, Test.class);

Add Jackson databind:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.0.pr2</version>
</dependency>
Create DTO class with related fields and read JSON file:
ObjectMapper objectMapper = new ObjectMapper();
ExampleClass example = objectMapper.readValue(new File("example.json"), ExampleClass.class);

Reading from JsonFile
public static ArrayList<Employee> readFromJsonFile(String fileName){
ArrayList<Employee> result = new ArrayList<Employee>();
try{
String text = new String(Files.readAllBytes(Paths.get(fileName)), StandardCharsets.UTF_8);
JSONObject obj = new JSONObject(text);
JSONArray arr = obj.getJSONArray("employees");
for(int i = 0; i < arr.length(); i++){
String name = arr.getJSONObject(i).getString("name");
short salary = Short.parseShort(arr.getJSONObject(i).getString("salary"));
String position = arr.getJSONObject(i).getString("position");
byte years_in_company = Byte.parseByte(arr.getJSONObject(i).getString("years_in_company"));
if (position.compareToIgnoreCase("manager") == 0){
result.add(new Manager(name, salary, position, years_in_company));
}
else{
result.add(new OrdinaryEmployee(name, salary, position, years_in_company));
}
}
}
catch(Exception ex){
System.out.println(ex.toString());
}
return result;
}

Use google-simple library.
<dependency>
<groupId>com.googlecode.json-simple</groupId>
<artifactId>json-simple</artifactId>
<version>1.1.1</version>
</dependency>
Please find the sample code below:
public static void main(String[] args) {
try {
JSONParser parser = new JSONParser();
//Use JSONObject for simple JSON and JSONArray for array of JSON.
JSONObject data = (JSONObject) parser.parse(
new FileReader("/resources/config.json"));//path to the JSON file.
String json = data.toJSONString();
} catch (IOException | ParseException e) {
e.printStackTrace();
}
}
Use JSONObject for simple JSON like {"id":"1","name":"ankur"} and JSONArray for array of JSON like [{"id":"1","name":"ankur"},{"id":"2","name":"mahajan"}].

Might be of help for someone else facing the same issue.You can load the file as string and then can convert the string to jsonobject to access the values.
import java.util.Scanner;
import org.json.JSONObject;
String myJson = new Scanner(new File(filename)).useDelimiter("\\Z").next();
JSONObject myJsonobject = new JSONObject(myJson);

Gson can be used here:
public Object getObjectFromJsonFile(String jsonData, Class classObject) {
Gson gson = new Gson();
JsonParser parser = new JsonParser();
JsonObject object = (JsonObject) parser.parse(jsonData);
return gson.fromJson(object, classObject);
}

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
public class Delete_01 {
public static void main(String[] args) throws FileNotFoundException,
IOException, ParseException {
JSONParser parser = new JSONParser();
JSONArray jsonArray = (JSONArray) parser.parse(new FileReader(
"delete_01.json"));
for (Object o : jsonArray) {
JSONObject person = (JSONObject) o;
String strName = (String) person.get("name");
System.out.println("Name::::" + strName);
String strCity = (String) person.get("city");
System.out.println("City::::" + strCity);
JSONArray arrays = (JSONArray) person.get("cars");
for (Object object : arrays) {
System.out.println("cars::::" + object);
}
String strJob = (String) person.get("job");
System.out.println("Job::::" + strJob);
System.out.println();
}
}
}

Following is the working solution to your problem statement as,
File file = new File("json-file.json");
JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader(file));
JSONArray jsonArray = new JSONArray(obj.toString());
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
System.out.println(jsonObject.get("name"));
System.out.println(jsonObject.get("city"));
System.out.println(jsonObject.get("job"));
jsonObject.getJSONArray("cars").forEach(System.out::println);
}

Hope this example helps too
I have done java coding in a similar way for the below json array example as follows :
following is the json data format : stored as "EMPJSONDATA.json"
[{"EMPNO":275172,"EMP_NAME":"Rehan","DOB":"29-02-1992","DOJ":"10-06-2013","ROLE":"JAVA DEVELOPER"},
{"EMPNO":275173,"EMP_NAME":"G.K","DOB":"10-02-1992","DOJ":"11-07-2013","ROLE":"WINDOWS ADMINISTRATOR"},
{"EMPNO":275174,"EMP_NAME":"Abiram","DOB":"10-04-1992","DOJ":"12-08-2013","ROLE":"PROJECT ANALYST"}
{"EMPNO":275174,"EMP_NAME":"Mohamed Mushi","DOB":"10-04-1992","DOJ":"12-08-2013","ROLE":"PROJECT ANALYST"}]
public class Jsonminiproject {
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
JSONArray a = (JSONArray) parser.parse(new FileReader("F:/JSON DATA/EMPJSONDATA.json"));
for (Object o : a)
{
JSONObject employee = (JSONObject) o;
Long no = (Long) employee.get("EMPNO");
System.out.println("Employee Number : " + no);
String st = (String) employee.get("EMP_NAME");
System.out.println("Employee Name : " + st);
String dob = (String) employee.get("DOB");
System.out.println("Employee DOB : " + dob);
String doj = (String) employee.get("DOJ");
System.out.println("Employee DOJ : " + doj);
String role = (String) employee.get("ROLE");
System.out.println("Employee Role : " + role);
System.out.println("\n");
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

package com.json;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
public class ReadJSONFile {
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("C:/My Workspace/JSON Test/file.json"));
JSONArray array = (JSONArray) obj;
JSONObject jsonObject = (JSONObject) array.get(0);
String name = (String) jsonObject.get("name");
System.out.println(name);
String city = (String) jsonObject.get("city");
System.out.println(city);
String job = (String) jsonObject.get("job");
System.out.println(job);
// loop array
JSONArray cars = (JSONArray) jsonObject.get("cars");
Iterator<String> iterator = cars.iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
}

This issue occurs when you are importing the org. json library for JSONObject class. Instead you need to import org.json.simple library.

private static final JsonParser JSON_PARSER = new JsonParser();
private static final String FILE_PATH = "configuration/data.json";
private JsonObject readJsonDataFromFile() {
try {
File indexFile = new File(FILE_PATH);
String fileData = Files.toString(indexFile, Charsets.UTF_8);
return (JsonObject) JSON_PARSER.parse(fileData);
} catch (IOException | JsonParseException e) {
String error = String.format("Error while reading file %s", FILE_PATH);
log.error(error);
throw new RuntimeException(error, e);
}
}

public class JsonParser {
public static JSONObject parse(String file) {
InputStream is = JsonParser.class.getClassLoader().getResourceAsStream(file);
assert is != null;
return new JSONObject(new JSONTokener(is));
}
}
// Read Json
JSONObject deviceObj = new JSONObject(JsonParser.parse("Your Json filename").getJSONObject(deviceID).toString());
Perform logic to iterate

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
public class JsonParserTest {
public static void main(String[] args) throws IOException {
String data = new String(Files.readAllBytes(Paths.get("C:/json.txt")));
JsonElement jsonElement = JsonParser.parseString(data);
JsonObject json = jsonElement.getAsJsonObject();
System.out.println(json.get("userId"));
System.out.println(json.get("id"));
System.out.println(json.get("title"));
System.out.println(json.get("completed"));
}
}
Use the below repositay from GSON.
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.6</version>
</dependency>

Sample Json
{
"per_page": 3,
"total": 12,
"data": [{
"last_name": "Bluth",
"id": 1,
"avatar": "https://s3.amazonaws.com/uifaces/faces/twitter/calebogden/128.jpg",
"first_name": "George"
},
{
"last_name": "Weaver",
"id": 2,
//"avatar": "https://s3.amazonaws.com/uifaces/faces/twitter/josephstein/128.jpg",
"first_name": "Janet"
},
{
"last_name": "Wong",
"id": 3,
//"avatar": "https://s3.amazonaws.com/uifaces/faces/twitter/olegpogodaev/128.jpg",
"first_name": "Emma"
}
],
"page": 1,
"total_pages": 4
}
First If statement will convert the single data from the body
Second if statement will differentiate the JsonArray object
public static String getvalueJpath(JSONObject responseJson, String Jpath ) {
Object obj = responseJson;
for(String s : Jpath.split("/"))
if (s.isEmpty())
if(!(s.contains("[") || s.contains("]")))
obj = ((JSONObject) obj).get(s);
else
if(s.contains("[") || s.contains("]"))
obj = ((JSONArray)((JSONObject)obj).get(s.split("\\[")[0])).get(Integer.parseInt(s.split("//[")[1].replaceAll("]", "")));
return obj.toString();
}
}

Solution using Jackson library. Sorted this problem by verifying the json on JSONLint.com and then using Jackson. Below is the code for the same.
Main Class:-
String jsonStr = "[{\r\n" + " \"name\": \"John\",\r\n" + " \"city\": \"Berlin\",\r\n"
+ " \"cars\": [\r\n" + " \"FIAT\",\r\n" + " \"Toyata\"\r\n"
+ " ],\r\n" + " \"job\": \"Teacher\"\r\n" + " },\r\n" + " {\r\n"
+ " \"name\": \"Mark\",\r\n" + " \"city\": \"Oslo\",\r\n" + " \"cars\": [\r\n"
+ " \"VW\",\r\n" + " \"Toyata\"\r\n" + " ],\r\n"
+ " \"job\": \"Doctor\"\r\n" + " }\r\n" + "]";
ObjectMapper mapper = new ObjectMapper();
MyPojo jsonObj[] = mapper.readValue(jsonStr, MyPojo[].class);
for (MyPojo itr : jsonObj) {
System.out.println("Val of getName is: " + itr.getName());
System.out.println("Val of getCity is: " + itr.getCity());
System.out.println("Val of getJob is: " + itr.getJob());
System.out.println("Val of getCars is: " + itr.getCars() + "\n");
}
POJO:
public class MyPojo {
private List<String> cars = new ArrayList<String>();
private String name;
private String job;
private String city;
public List<String> getCars() {
return cars;
}
public void setCars(List<String> cars) {
this.cars = cars;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getJob() {
return job;
}
public void setJob(String job) {
this.job = job;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
} }
RESULT:-
Val of getName is: John
Val of getCity is: Berlin
Val of getJob is: Teacher
Val of getCars is: [FIAT, Toyata]
Val of getName is: Mark
Val of getCity is: Oslo
Val of getJob is: Doctor
Val of getCars is: [VW, Toyata]

your json file look like this
import java.io.*;
import java.util.*;
import org.json.simple.*;
import org.json.simple.parser.*;
public class JSONReadFromTheFileTest {
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("/Users/User/Desktop/course.json"));
JSONObject jsonObject = (JSONObject)obj;
String name = (String)jsonObject.get("Name");
String course = (String)jsonObject.get("Course");
JSONArray subjects = (JSONArray)jsonObject.get("Subjects");
System.out.println("Name: " + name);
System.out.println("Course: " + course);
System.out.println("Subjects:");
Iterator iterator = subjects.iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next());
}
} catch(Exception e) {
e.printStackTrace();
}
}
}
the output is
Name: Raja
Course: MCA
Subjects:
subject1: MIS
subject2: DBMS
subject3: UML
took it from here

try {
Object obj = parser.parse(new FileReader("C:/Local Disk/file.json"));
// JSONArray array = (JSONArray) obj;
JSONObject jsonObject = (JSONObject) obj;
JSONObject orchestration = (JSONObject) jsonObject.get("orchestration");
JSONObject trigger = (JSONObject) orchestration.get("trigger-definition");
JSONObject schedule = (JSONObject) trigger.get("schedule");
JSONObject trade = (JSONObject) schedule.get("trade-query");
// loop array
JSONArray filter = (JSONArray) trade.get("filter");
for (Object o : filter) {
JSONObject person = (JSONObject) o;
String strName = (String) person.get("name");
System.out.println("Name::::" + strName);
String operand = (String) person.get("operand");
System.out.println("City::::" + operand);
String value = (String) person.get("value");
System.out.println("value::::" + value);
}
JSONArray parameter = (JSONArray) trade.get("parameter");
for (Object o : parameter) {
JSONObject person = (JSONObject) o;
String strName = (String) person.get("name");
System.out.println("Name::::" + strName);
String value = (String) person.get("value");
System.out.println("value::::" + value);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}

try {
//Object obj = parser.parse(new FileReader("C:/Local Disk/file.json"));
// create object mapper instance
ObjectMapper mapper = new ObjectMapper();
// convert JSON string to Book object
Object obj = mapper.readValue(Paths.get("C:/Local Disk/file.json").toFile(), Object.class);
// print book
System.out.println(obj);
String jsonInString = new Gson().toJson(obj);
JSONObject mJSONObject = new JSONObject(jsonInString);
System.out.println("value::::" + mJSONObject);
JSONObject orchestration = (JSONObject) mJSONObject.get("orchestration");
JSONObject trigger = (JSONObject) orchestration.get("trigger-definition");
JSONObject schedule = (JSONObject) trigger.get("schedule");
JSONObject trade = (JSONObject) schedule.get("trade-query");
// loop array
JSONArray filter = (JSONArray) trade.get("filter");
for (Object o : filter) {
JSONObject person = (JSONObject) o;
String strName = (String) person.get("name");
System.out.println("Name::::" + strName);
String operand = (String) person.get("operand");
System.out.println("City::::" + operand);
String value = (String) person.get("value");
System.out.println("value::::" + value);
}
JSONArray parameter = (JSONArray) trade.get("parameter");
for (Object o : parameter) {
JSONObject person = (JSONObject) o;
String strName = (String) person.get("name");
System.out.println("Name::::" + strName);
String value = (String) person.get("value");
System.out.println("value::::" + value);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

You can use readAllBytes.
return String(Files.readAllBytes(Paths.get(filePath)),StandardCharsets.UTF_8);

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