I am trying to extract a value from a while loop. In the output, I am able to capture the value in the Else statement but not able to return it when it is in the console log from the main statement. I want to be able to return "103" when I call the getValueFromkey() function.
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Iterator;
import org.json.JSONArray;
import org.json.JSONObject;
import org.json.XML;
public class Tesst {
static String line = "", str = "";
public static void main(String[] args) throws Exception {
String filepath = "C:/Users/Navi/Downloads/sample.xml";
BufferedReader br = new BufferedReader(new FileReader(filepath));
while ((line = br.readLine()) != null) {
str += line;
}
br.close();
JSONObject jsondata = XML.toJSONObject(str);
System.out.println("From main: " + getValueFromKey(jsondata, "routing_bic"));
}
private static Integer getValueFromKey(JSONObject json, String key) {
boolean exists = json.has(key);
Iterator<?> keys;
String nextKeys;
Integer foundKey = 0;
if(!exists) {
keys = json.keys();
while (keys.hasNext()) {
// Store next Key in nextKeys
nextKeys = (String)keys.next();
try {
// Check if the given Key is a JSON Object
if(json.get(nextKeys) instanceof JSONObject) {
// If Key does not exist
if(!exists) {
// Recursive function call
getValueFromKey(json.getJSONObject(nextKeys), key);
}
} else if (json.get(nextKeys) instanceof JSONArray) {
JSONArray jsonArray = json.getJSONArray(nextKeys);
for(int i = 0; i < jsonArray.length(); i++) {
String jsonArrayString = jsonArray.get(i).toString();
JSONObject innerJsonObject = new JSONObject(jsonArrayString);
// Recursive function call
if(!exists) {
getValueFromKey(innerJsonObject.getJSONObject(nextKeys), key);
}
}
}
} catch (Exception e) {
System.out.println(e);
}
}
} else {
// If key exists, print value
foundKey += parseObject(json, key);
System.out.println("From loop: " + foundKey);
return foundKey;
}
// System.out.println("Found Key = " + foundKey);
return 1; // Return 1 when key not found
}
private static Integer parseObject(JSONObject json, String key) {
System.out.println("From parseObject = " + json.get(key));
return (Integer) json.get(key);
}
}
Sample XML
<Test>
<BIBRq>
<UserId>123</UserId>
<CIFNo>123</CIFNo>
<CompanyId>asd</CompanyId>
<LegalId>123</LegalId>
<LegalIdType>ABC</LegalIdType>
<LegalIdCountry>ABC</LegalIdCountry>
</BIBRq>
<SubSvcRq>
<SubSvc>
<SubSvcRqHeader>
<SvcCode>ABCD</SvcCode>
<SubSvcSeq>1</SubSvcSeq>
<TxnRef>12345</TxnRef>
<ClientUserID/>
</SubSvcRqHeader>
<SubSvcRqDetail>
<ft_tnx_record>
<additional_field>
<account_details>
<routing_bic>103</routing_bic>
</account_details>
</additional_field>
</ft_tnx_record>
</SubSvcRqDetail>
</SubSvc>
</SubSvcRq>
</Test>
Output:
From parseObject = 103
From loop: 103
From main: 1
There are two errors in your code.
I notice that you recursively call the function getValueFromKey. That will never work if you don't assign the variable foundKey with the return value of the recursive invocation.
So, just change each recursive calls in this:
foundKey = getValueFromKey(..., key);
In addition, the last statement return 1 is wrong, because it will override any possible value returned by the subsequent recursive invocation. So, in replacement, you have to return always the foundKey variable.
I slightly changed your code and tested it with your sample file and it works fine. Differently than yours, I also wrapped the BufferedReader with try-with-resouce block, which I always prefer to simple try-catch, because it garantees that it closes the stream for you, even in case of exceptions.
Here is the code:
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.Iterator;
import org.json.JSONArray;
import org.json.JSONObject;
import org.json.XML;
public class Test {
static String line = "", str = "";
public static void main(String[] args) throws Exception {
String filepath = "C:\\Users\\marco\\Downloads\\sample.xml";
try ( BufferedReader br = new BufferedReader(new FileReader(filepath)); ) {
while ((line = br.readLine()) != null) {
str += line;
}
}
JSONObject jsondata = XML.toJSONObject(str);
System.out.println("From main: " + getValueFromKey(jsondata, "routing_bic"));
}
private static Integer getValueFromKey(JSONObject json, String key) {
boolean exists = json.has(key);
Iterator<?> keys;
String nextKeys;
Integer foundKey = 0;
if(!exists) {
keys = json.keys();
while (keys.hasNext()) {
// Store next Key in nextKeys
nextKeys = (String)keys.next();
try {
// Check if the given Key is a JSON Object
if(json.get(nextKeys) instanceof JSONObject) {
// If Key does not exist
if(!exists) {
// Recursive function call
foundKey = getValueFromKey(json.getJSONObject(nextKeys), key);
}
} else if (json.get(nextKeys) instanceof JSONArray) {
JSONArray jsonArray = json.getJSONArray(nextKeys);
for(int i = 0; i < jsonArray.length(); i++) {
String jsonArrayString = jsonArray.get(i).toString();
JSONObject innerJsonObject = new JSONObject(jsonArrayString);
// Recursive function call
if(!exists) {
foundKey = getValueFromKey(innerJsonObject.getJSONObject(nextKeys), key);
}
}
}
} catch (Exception e) {
System.out.println(e);
}
}
} else {
// If key exists, print value
foundKey += parseObject(json, key);
System.out.println("From loop: " + foundKey);
}
// System.out.println("Found Key = " + foundKey);
return foundKey; // Return 1 when key not found
}
private static Integer parseObject(JSONObject json, String key) {
System.out.println("From parseObject = " + json.get(key));
return (Integer) json.get(key);
}
}
And here is the output:
From parseObject = 103
From loop: 103
From main: 103
I'm using json-simple and I need to pretty-print JSON data (make it more human readable).
I haven't been able to find this functionality within that library.
How is this commonly achieved?
Google's GSON can do this in a nice way:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonParser jp = new JsonParser();
JsonElement je = jp.parse(uglyJsonString);
String prettyJsonString = gson.toJson(je);
or since it is now recommended to use the static parse method from JsonParser you can also use this instead:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonElement je = JsonParser.parseString(uglyJsonString);
String prettyJsonString = gson.toJson(je);
Here is the import statement:
import com.google.gson.*;
Here is the Gradle dependency:
implementation 'com.google.code.gson:gson:2.8.7'
I used org.json built-in methods to pretty-print the data.
import org.json.JSONObject;
JSONObject json = new JSONObject(jsonString); // Convert text to object
System.out.println(json.toString(4)); // Print it with specified indentation
The order of fields in JSON is random per definition. A specific order is subject to parser implementation.
With Jackson (com.fasterxml.jackson.databind):
ObjectMapper mapper = new ObjectMapper();
System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonObject))
From: How to enable pretty print JSON output (Jackson)
I know this is already in the answers, but I want to write it separately here because chances are, you already have Jackson as a dependency and so all you will need would be an extra line of code
It seems like GSON supports this, although I don't know if you want to switch from the library you are using.
From the user guide:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
String jsonOutput = gson.toJson(someObject);
Using org json. Reference link
JSONObject jsonObject = new JSONObject(obj);
String prettyJson = jsonObject.toString(4);
Using Gson. Reference link
Gson gson = new GsonBuilder().setPrettyPrinting().create();
String json = gson.toJson(obj);
Using Jackson. Reference link
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
String json = mapper.writeValueAsString(obj);
Using Genson. Reference link.
Genson prettyGenson = new GensonBuilder().useIndentation(true).create();
String prettyJson = prettyGenson.serialize(obj);
Using javax.json. Reference link.
Map<String, Boolean> config = new HashMap<>();
config.put(JsonGenerator.PRETTY_PRINTING, true);
JsonWriterFactory writerFactory = Json.createWriterFactory(config);
Writer writer = new StringWriter();
writerFactory.createWriter(writer).write(jsonObject);
String json = writer.toString();
Using Moshi library. Reference link.
String json = jsonAdapter.indent(" ").toJson(emp1);
(OR)
Buffer buffer = new Buffer();
JsonWriter jsonWriter = JsonWriter.of(buffer);
jsonWriter.setIndent(" ");
jsonAdapter.toJson(jsonWriter, emp1);
json = buffer.readUtf8();
If you are using a Java API for JSON Processing (JSR-353) implementation then you can specify the JsonGenerator.PRETTY_PRINTING property when you create a JsonGeneratorFactory.
The following example has been originally published on my blog post.
import java.util.*;
import javax.json.Json;
import javax.json.stream.*;
Map<String, Object> properties = new HashMap<String, Object>(1);
properties.put(JsonGenerator.PRETTY_PRINTING, true);
JsonGeneratorFactory jgf = Json.createGeneratorFactory(properties);
JsonGenerator jg = jgf.createGenerator(System.out);
jg.writeStartObject() // {
.write("name", "Jane Doe") // "name":"Jane Doe",
.writeStartObject("address") // "address":{
.write("type", 1) // "type":1,
.write("street", "1 A Street") // "street":"1 A Street",
.writeNull("city") // "city":null,
.write("verified", false) // "verified":false
.writeEnd() // },
.writeStartArray("phone-numbers") // "phone-numbers":[
.writeStartObject() // {
.write("number", "555-1111") // "number":"555-1111",
.write("extension", "123") // "extension":"123"
.writeEnd() // },
.writeStartObject() // {
.write("number", "555-2222") // "number":"555-2222",
.writeNull("extension") // "extension":null
.writeEnd() // }
.writeEnd() // ]
.writeEnd() // }
.close();
Pretty printing with GSON in one line:
System.out.println(new GsonBuilder().setPrettyPrinting().create().toJson(new JsonParser().parse(jsonString)));
Besides inlining, this is equivalent to the accepted answer.
My situation is my project uses a legacy (non-JSR) JSON parser that does not support pretty printing. However, I needed to produce pretty-printed JSON samples; this is possible without having to add any extra libraries as long as you are using Java 7 and above:
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine scriptEngine = manager.getEngineByName("JavaScript");
scriptEngine.put("jsonString", jsonStringNoWhitespace);
scriptEngine.eval("result = JSON.stringify(JSON.parse(jsonString), null, 2)");
String prettyPrintedJson = (String) scriptEngine.get("result");
Most of the existing answers either depend on some external library, or requiring a special Java version. Here is a simple code to pretty print a JSON string, only using general Java APIs (available in Java 7 for higher; haven't tried older version although).
The basic idea is to tigger the formatting based on special characters in JSON. For example, if a '{' or '[' is observed, the code will create a new line and increase the indent level.
Disclaimer: I only tested this for some simple JSON cases (basic key-value pair, list, nested JSON) so it may need some work for more general JSON text, like string value with quotes inside, or special characters (\n, \t etc.).
/**
* A simple implementation to pretty-print JSON file.
*
* #param unformattedJsonString
* #return
*/
public static String prettyPrintJSON(String unformattedJsonString) {
StringBuilder prettyJSONBuilder = new StringBuilder();
int indentLevel = 0;
boolean inQuote = false;
for(char charFromUnformattedJson : unformattedJsonString.toCharArray()) {
switch(charFromUnformattedJson) {
case '"':
// switch the quoting status
inQuote = !inQuote;
prettyJSONBuilder.append(charFromUnformattedJson);
break;
case ' ':
// For space: ignore the space if it is not being quoted.
if(inQuote) {
prettyJSONBuilder.append(charFromUnformattedJson);
}
break;
case '{':
case '[':
// Starting a new block: increase the indent level
prettyJSONBuilder.append(charFromUnformattedJson);
indentLevel++;
appendIndentedNewLine(indentLevel, prettyJSONBuilder);
break;
case '}':
case ']':
// Ending a new block; decrese the indent level
indentLevel--;
appendIndentedNewLine(indentLevel, prettyJSONBuilder);
prettyJSONBuilder.append(charFromUnformattedJson);
break;
case ',':
// Ending a json item; create a new line after
prettyJSONBuilder.append(charFromUnformattedJson);
if(!inQuote) {
appendIndentedNewLine(indentLevel, prettyJSONBuilder);
}
break;
default:
prettyJSONBuilder.append(charFromUnformattedJson);
}
}
return prettyJSONBuilder.toString();
}
/**
* Print a new line with indention at the beginning of the new line.
* #param indentLevel
* #param stringBuilder
*/
private static void appendIndentedNewLine(int indentLevel, StringBuilder stringBuilder) {
stringBuilder.append("\n");
for(int i = 0; i < indentLevel; i++) {
// Assuming indention using 2 spaces
stringBuilder.append(" ");
}
}
Now this can be achieved with the JSONLib library:
http://json-lib.sourceforge.net/apidocs/net/sf/json/JSONObject.html
If (and only if) you use the overloaded toString(int indentationFactor) method and not the standard toString() method.
I have verified this on the following version of the API:
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20140107</version>
</dependency>
Following the JSON-P 1.0 specs (JSR-353) a more current solution for a given JsonStructure (JsonObject or JsonArray) could look like this:
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;
import javax.json.Json;
import javax.json.JsonStructure;
import javax.json.JsonWriter;
import javax.json.JsonWriterFactory;
import javax.json.stream.JsonGenerator;
public class PrettyJson {
private static JsonWriterFactory FACTORY_INSTANCE;
public static String toString(final JsonStructure status) {
final StringWriter stringWriter = new StringWriter();
final JsonWriter jsonWriter = getPrettyJsonWriterFactory()
.createWriter(stringWriter);
jsonWriter.write(status);
jsonWriter.close();
return stringWriter.toString();
}
private static JsonWriterFactory getPrettyJsonWriterFactory() {
if (null == FACTORY_INSTANCE) {
final Map<String, Object> properties = new HashMap<>(1);
properties.put(JsonGenerator.PRETTY_PRINTING, true);
FACTORY_INSTANCE = Json.createWriterFactory(properties);
}
return FACTORY_INSTANCE;
}
}
In JSONLib you can use this:
String jsonTxt = JSONUtils.valueToString(json, 8, 4);
From the Javadoc:
You can use Gson like below
Gson gson = new GsonBuilder().setPrettyPrinting().create();
String jsonString = gson.toJson(object);
From the post JSON pretty print using Gson
Alternatively, You can use Jackson like below
ObjectMapper mapper = new ObjectMapper();
String perttyStr = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(object);
From the post Pretty print JSON in Java (Jackson)
Hope this help!
Update: new JsonParser().parse(...) is #deprecated
Based on the javadoc for Gson 2.8.6:
No need to instantiate this class, use the static methods instead.
JsonParser static methods:
JsonParser.parseString(jsonString);
JsonParser.parseReader(reader);
Packages:
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonParser;
Example:
private Gson GSON = new GsonBuilder().setPrettyPrinting().create();
public static String getPerfectJSON(String unformattedJSON) {
String perfectJSON = GSON.toJson(JsonParser.parseString(unformattedJSON));
return perfectJSON;
}
Google Gson dependency using Maven:
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.6</version>
</dependency>
Reference:
JsonParser is deprecated
This worked for me, using Jackson:
mapper.writerWithDefaultPrettyPrinter().writeValueAsString(JSONString)
So I too like the json-simple lib, and looked into pretty printing its output. Unfortunately, while it's an open issue there, I couldn't find any code for it. So I thought I'd give it a try, here's what I came up with (using their own source)..
public class JsonPrinter {
public static String toJson(Map<?,?> map) {
StringBuilder out = new StringBuilder(32);
new JsonPrinter(out).print(map);
return out.toString();
}
public static String toJson(List<?> list) {
StringBuilder out = new StringBuilder(32);
new JsonPrinter(out).print(list);
return out.toString();
}
private final Appendable out;
private final String indentUnit;
private final String newLine;
private int indents;
public JsonPrinter(Appendable out) {
this(out, " ", System.lineSeparator());
}
/**
*
*/
public JsonPrinter(Appendable out, String indentUnit, String newLine) {
this.out = Objects.requireNonNull(out, "null out");
this.indentUnit = Objects.requireNonNull(indentUnit, "null indentUnit");
this.newLine = Objects.requireNonNull(newLine, "null newLine");
if (!indentUnit.isBlank())
throw new IllegalArgumentException(
"indentUnit must be a blank sequence (quoted): '" + indentUnit + "'");
if (!"\r\n".equals(newLine) && ! "\n".equals(newLine))
throw new IllegalArgumentException(
"unrecognized newLine (quoted): '" + newLine + "'");
}
public void print(List<?> list) throws UncheckedIOException {
try {
assert indents == 0;
printImpl(list);
assert indents == 0;
} catch (IOException iox) {
throw new UncheckedIOException("on print(List): " + list, iox);
}
}
public void print(Map<?,?> map) throws UncheckedIOException {
try {
assert indents == 0;
printImpl(map);
assert indents == 0;
} catch (IOException iox) {
throw new UncheckedIOException("on print(Map): " + map, iox);
}
}
protected void printImpl(List<?> list) throws IOException {
if (list == null) {
out.append("null");
return;
}
boolean first = true;
var iter = list.iterator();
open('[');
while (iter.hasNext()) {
if (first)
first = false;
else
out.append(',');
out.append(newLine);
appendIndents();
appendValue(iter.next());
}
close(']');
}
protected void printImpl(Map<?, ?> map) throws IOException {
if (map == null) {
out.append("null");
return;
}
boolean first = true;
var iter = map.entrySet().iterator();
open('{');
while (iter.hasNext()) {
if (first)
first = false;
else
out.append(',');
out.append(newLine);
appendIndents();
var entry = iter.next();
print(entry.getKey().toString(), entry.getValue());
}
close('}');
}
private void open(char c) throws IOException {
out.append(c);
++indents;
}
private void close(char c) throws IOException {
--indents;
out.append(newLine);
appendIndents();
out.append(c);
}
private void appendIndents() throws IOException {
for (int count = indents; count-- > 0; )
out.append(indentUnit);
}
private void print(String key, Object value) throws IOException {
out.append('"');
appendString(key);
out.append('"').append(':').append(' ');
appendValue(value);
}
private void appendString(String s) throws IOException {
for (int i = 0; i < s.length(); i++) {
char ch = s.charAt(i);
switch(ch){
case '"':
out.append("\\\"");
break;
case '\\':
out.append("\\\\");
break;
case '\b':
out.append("\\b");
break;
case '\f':
out.append("\\f");
break;
case '\n':
out.append("\\n");
break;
case '\r':
out.append("\\r");
break;
case '\t':
out.append("\\t");
break;
case '/':
out.append("\\/");
break;
default:
//Reference: http://www.unicode.org/versions/Unicode5.1.0/
if ((ch>='\u0000' && ch<='\u001F') || (ch>='\u007F' && ch<='\u009F') || (ch>='\u2000' && ch<='\u20FF')) {
String ss = Integer.toHexString(ch);
out.append("\\u");
for (int k=0; k < 4-ss.length(); k++) {
out.append('0');
}
out.append(ss.toUpperCase());
}
else{
out.append(ch);
}
}
}//for
}
private void appendValue(Object value) throws IOException {
if (value == null) {
out.append("null");
} else if (value instanceof String) {
out.append('"');
appendString(value.toString());
out.append('"');
} else if (value instanceof Double) {
var num = (Double) value;
if (num.isInfinite() || num.isNaN())
out.append("null");
else
out.append(value.toString());
} else if (value instanceof Float) {
var num = (Float) value;
if (num.isInfinite() || num.isNaN())
out.append("null");
else
out.append(value.toString());
} else if (value instanceof Map) {
printImpl((Map<?,?>) value);
} else if (value instanceof List) {
printImpl((List<?>) value);
// } else if (value instanceof Number || value instanceof Boolean) {
// out.append(value.toString());
} else {
out.append(value.toString());
}
}
}
It works for JSONObject and JSONArray even tho it has no dependeny on them.. cuz these are regular Map and List objects resp. (and the fact code was lifted from same lib).
https://github.com/crums-io/io-util/blob/master/src/main/java/io/crums/util/json/JsonPrinter.java
You can use small json library
String jsonstring = ....;
JsonValue json = JsonParser.parse(jsonstring);
String jsonIndendedByTwoSpaces = json.toPrettyString(" ");
I also use the org.json.simple package. I have simply coded the formatter, but since I don't have nulls, numbers or booleans in my JSON objects in the program that I wrote, I only coded for strings, objects and arrays. If anyone is interested, let this just be in the public domain. You are welcome to add the missing data types (where it says in the comment "it's a string"). Also, you can add the indentation as a parameter whereas mine is just two spaces. Please reshare after you've tested your improvements.
Usage: printJsonObject(jsonObject, "");
Functions:
public static void printJsonObject(JSONObject object, String prefix) {
boolean notFirst = false;
System.out.println(prefix + "{");
for (Object key : object.keySet()) {
if (notFirst) {
System.out.println(", ");
}
notFirst = true;
Object value = object.get(key);
System.out.print(prefix + " " + "\"" + key + "\"" + ": ");
if (value instanceof JSONObject) {
printJsonObject((JSONObject) value, prefix + " ");
} else if (value instanceof JSONArray) {
printJsonArray((JSONArray) value, prefix + " ");
} else { // it's a string
System.out.print("\"" + value + "\"");
}
}
System.out.println("");
System.out.print(prefix + "}");
}
public static void printJsonArray(JSONArray array, String prefix) {
boolean notFirst = false;
System.out.println("[");
for (Object item : array) {
if (notFirst) {
System.out.println(", ");
}
notFirst = true;
if (item instanceof JSONObject) {
printJsonObject((JSONObject) item, prefix + " ");
} else if (item instanceof JSONArray) {
printJsonArray((JSONArray) item, prefix + " ");
} else {
System.out.print(prefix + " " + "\"" + item + "\"");
}
}
System.out.println("");
System.out.print(prefix + "]");
}
This would be a public method to print a pretty version of your object (You need the Gson dependency installed:
import com.google.gson.GsonBuilder;
...
public void printMe(){
Gson gson = new GsonBuilder().setPrettyPrinting().create();
String prettyJSON = gson.toJson(this);
System.out.println(printable);
}
Underscore-java has static method U.formatJson(json).
Five format types are supported: 2, 3, 4, tabs and compact. Live example
import com.github.underscore.U;
import static com.github.underscore.Json.JsonStringBuilder.Step.TABS;
import static com.github.underscore.Json.JsonStringBuilder.Step.TWO_SPACES;
public class MyClass {
public static void main(String args[]) {
String json = "{\"Price\": {"
+ " \"LineItems\": {"
+ " \"LineItem\": {"
+ " \"UnitOfMeasure\": \"EACH\", \"Quantity\": 2, \"ItemID\": \"ItemID\""
+ " }"
+ " },"
+ " \"Currency\": \"USD\","
+ " \"EnterpriseCode\": \"EnterpriseCode\""
+ "}}";
System.out.println(U.formatJson(json, TWO_SPACES));
System.out.println(U.formatJson(json, TABS));
}
}
Output:
{
"Price": {
"LineItems": {
"LineItem": {
"UnitOfMeasure": "EACH",
"Quantity": 2,
"ItemID": "ItemID"
}
},
"Currency": "USD",
"EnterpriseCode": "EnterpriseCode"
}
}
{
"Price": {
"LineItems": {
"LineItem": {
"UnitOfMeasure": "EACH",
"Quantity": 2,
"ItemID": "ItemID"
}
},
"Currency": "USD",
"EnterpriseCode": "EnterpriseCode"
}
}
I am printing a value in a file i need to split them onces the first content is finished leave some spaces and then print the next one
public class Test_Json {
public static ArrayList<Object> ls1 = new ArrayList<Object>();
public static ArrayList<Object> ls2 = new ArrayList<Object>();
public static void main(String[] args) throws Exception {
JsonParser parser = new JsonParser();
BufferedWriter bw = null;
FileWriter fw = null;
try {
Gson g = new Gson();
JsonElement jsonElement1 = parser.parse(new FileReader("D://sample1.json"));
JsonElement jsonElement2 = parser.parse(new FileReader("D://sample2.json"));
// System.out.println("Is the two JSON File Same: "+compareJson(jsonElement1,jsonElement2));
if (!compareJson(jsonElement1, jsonElement2)) {
Type mapType = new TypeToken<Map<String, Object>>() {
}.getType();
Map<String, Object> firstMap = g
.fromJson(jsonElement1, mapType);
Map<String, Object> secondMap = g.fromJson(jsonElement2,
mapType);
System.out.println(" The Two JSON Files Are Not the Same ");
System.out.println(Maps.difference(firstMap, secondMap));
String s = Maps.difference(firstMap, secondMap).toString();
try{
fw = new FileWriter("D:\\output.txt");
bw = new BufferedWriter(fw);
bw.write(s);
}catch(Exception e){
e.printStackTrace();
}
} else {
System.out.println("The Two JSON Are SAME!!!!!!!!!!!!!!!");
}
} catch (Exception e1) {
e1.printStackTrace();
}
}
public static boolean compareJson(JsonElement json1, JsonElement json2) {
boolean isEqual = true;
if (json1 != null && json2 != null) {
if (json1.isJsonObject() && json2.isJsonObject()) {
Set<Entry<String, JsonElement>> ens1 = ((JsonObject) json1)
.entrySet();
Set<Entry<String, JsonElement>> ens2 = ((JsonObject) json2)
.entrySet();
JsonObject json2obj = (JsonObject) json2;
if (ens1 != null && ens2 != null
&& (ens2.size() == ens1.size())) {
for (Entry<String, JsonElement> en : ens1) {
isEqual = isEqual
&& compareJson(en.getValue(),
json2obj.get(en.getKey()));
}
} else {
return false;
}
}
else if (json1.isJsonArray() && json2.isJsonArray()) {
JsonArray jarr1 = json1.getAsJsonArray();
JsonArray jarr2 = json2.getAsJsonArray();
if (jarr1.size() != jarr2.size()) {
return false;
} else {
int i = 0;
for (JsonElement je : jarr1) {
isEqual = isEqual && compareJson(je, jarr2.get(i));
i++;
}
if (isEqual) {
ls1.toArray();
ls2.toArray();
isEqual = ls1.containsAll(ls2);
}
}
}
else if (json1.isJsonNull() && json2.isJsonNull()) {
return true;
}
else if (json1.isJsonPrimitive() && json2.isJsonPrimitive()) {
ls1.add(json1);
ls2.add(json2);
return true;
}
else if((json1.isJsonPrimitive() & json2.isJsonArray()) || (json2.isJsonPrimitive() && json1.isJsonArray())){
return false;
}
} else if (json1 == null && json2 == null) {
return true;
} else {
return false;
}
return isEqual;
}
}
Map.difference method gets the difference form the two file and prints them. I need to first print first file difference and then leave some lines of space and print the next file difference. This i am doing to show the contents seperately. At present it is displaying without any spaces so identifying is difficult.
I need something like this
Difference values in first file:
{
"id": 1,
"name": "A green door",
"price": 12.50,
"tags": ["home", "green"]
}
Difference in second file:
{
"id": 14,
"name": "A green door bell",
"price": 127.50,
"tags": ["home", "green"]
}
The method entriesOnlyOnLeft() and entriesOnlyOnRight() is not displaying the differece as the key should be different but here the key are same
If you want to print the map differences with a separation between the left and right sides, you can get them separately from the MapDifference result:
MapDifference diff = Maps.difference(firstMap, secondMap);
bw.write("Only on left: " + diff.entriesOnlyOnLeft());
// add separation
bw.write("Only on right: " + diff.entriesOnlyOnRight());
To include the value differences:
bw.write("Value differences: " + diff.entriesDiffering());
I have a sample JSON payload that looks like this:
{"timestamp": 1427394360, "device": {"user-agent": "Mac OS 10.10.2 2.6 GHz Intel Core i7"}}
I parse it and get the key / value pairs using this:
Iterator<Map.Entry<String,JsonNode>> fieldsIterator = rootNode.fields();
while (fieldsIterator.hasNext()) {
Map.Entry<String,JsonNode> field = fieldsIterator.next();
key = field.getKey();
value = field.getValue();
System.out.println("Key: " + key);
System.out.println("Value: " + value);
}
This outputs:
Key: timestamp
Value: 1427394360
Key: device
Value: {"user-agent": "Mac OS 10.10.2 2.6 GHz Intel Core i7"}
How can I set it up so I can parse out the key / value pair inside the device key to become:
Key: "user-agent"
Value: "Mac OS 10.10.2 2.6 GHz Intel Core i7"
And also, there might be JSON that has even more nested JSON inside it...
Meaning that some JSON might have no nested JSON and some might have multiple...
Is there a way to recursively parse all the key / value pairs from a JSON payload using Jackson?
Thank you for taking the time to read this...
You can place your code in a method and make a recursive call if the value is container (Ex: array or object).
For example:
public static void main(String[] args) throws IOException {
ObjectMapper mapper = new ObjectMapper();
final JsonNode rootNode = mapper.readTree(" {\"timestamp\": 1427394360, \"device\": {\"user-agent\": \"Mac OS 10.10.2 2.6 GHz Intel Core i7\"}}");
print(rootNode);
}
private static void print(final JsonNode node) throws IOException {
Iterator<Map.Entry<String, JsonNode>> fieldsIterator = node.getFields();
while (fieldsIterator.hasNext()) {
Map.Entry<String, JsonNode> field = fieldsIterator.next();
final String key = field.getKey();
System.out.println("Key: " + key);
final JsonNode value = field.getValue();
if (value.isContainerNode()) {
print(value); // RECURSIVE CALL
} else {
System.out.println("Value: " + value);
}
}
}
Below code will help you to parse and fetch required value using Jackson library.
public class GetJsonKeyValueUsingRecursion {
static String value;
public static void main(String[] args) throws JsonProcessingException, IOException {
JsonNode rootPage = new ObjectMapper()
.readTree(new File("C:/employee.json"));
// System.out.println(rootPage);
JsonNode std = rootPage.path("Student");
System.out.println(std);
//Call recursive json parser with node name and key name whose values is required
String value = parseJsonRecursively(std, "SSC");
System.out.println("Searched value: " + value);
}
static boolean flag = false;
private static String parseJsonRecursively(JsonNode rootNode, String expectedKey) {
value = null;
try {
if (rootNode.isArray() && rootNode.isContainerNode()) {
System.out.println("In array Root node is: " + rootNode);
for (JsonNode objNode: rootNode) {
if (flag) {
break;
} else if (objNode.isValueNode()) {
} else {
parseJsonRecursively(objNode, expectedKey);
}
}
} else if (rootNode.isValueNode()) {
value = rootNode.asText();
return value;
} else if (rootNode.isContainerNode()) {
Iterator < String > subItemItrator = rootNode.fieldNames();
while (subItemItrator.hasNext() && !flag) {
String targetKey = subItemItrator.next();
System.out.println("Target Key: " + targetKey);
if (targetKey.equals(expectedKey)) {
value = rootNode.path(targetKey).asText();
System.out.println("Matched :-----> " + targetKey + " = " + expectedKey + " Value: " + value);
flag = true;
return value;
} else if (!rootNode.path(targetKey).isValueNode() && flag == false) {
parseJsonRecursively(rootNode.path(targetKey), expectedKey);
}
}
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return value;
}
}
If I was the developer of this code, I would rather user an existing JSON library (such as Jackson or GSON) to accomplish this.
Below is one of the examples, to parse the JSON representation of list of objects.
URL: http://www.studytrails.com/java/json/java-jackson-Serialization-list.jsp
I am working on a very simple application for a website, just a basic desktop application.
So I've figured out how to grab all of the JSON Data I need, and if possible, I am trying to avoid the use of external libraries to parse the JSON.
Here is what I am doing right now:
package me.thegreengamerhd.TTVPortable;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import me.thegreengamerhd.TTVPortable.Utils.Messenger;
public class Channel
{
URL url;
String data;
String[] dataArray;
String name;
boolean online;
int viewers;
int followers;
public Channel(String name)
{
this.name = name;
}
public void update() throws IOException
{
// grab all of the JSON data from selected channel, if channel exists
try
{
url = new URL("https://api.twitch.tv/kraken/channels/" + name);
URLConnection connection = url.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
data = new String(in.readLine());
in.close();
// clean up data a little, into an array
dataArray = data.split(",");
}
// channel does not exist, throw exception and close client
catch (Exception e)
{
Messenger.sendErrorMessage("The channel you have specified is invalid or corrupted.", true);
e.printStackTrace();
return;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < dataArray.length; i++)
{
sb.append(dataArray[i] + "\n");
}
System.out.println(sb.toString());
}
}
So here is what is printed when I enter an example channel (which grabs data correctly)
{"updated_at":"2013-05-24T11:00:26Z"
"created_at":"2011-06-28T07:50:25Z"
"status":"HD [XBOX] Call of Duty Black Ops 2 OPEN LOBBY"
"url":"http://www.twitch.tv/zetaspartan21"
"_id":23170407
"game":"Call of Duty: Black Ops II"
"logo":"http://static-cdn.jtvnw.net/jtv_user_pictures/zetaspartan21-profile_image-121d2cb317e8a91c-300x300.jpeg"
"banner":"http://static-cdn.jtvnw.net/jtv_user_pictures/zetaspartan21-channel_header_image-7c894f59f77ae0c1-640x125.png"
"_links":{"subscriptions":"https://api.twitch.tv/kraken/channels/zetaspartan21/subscriptions"
"editors":"https://api.twitch.tv/kraken/channels/zetaspartan21/editors"
"commercial":"https://api.twitch.tv/kraken/channels/zetaspartan21/commercial"
"teams":"https://api.twitch.tv/kraken/channels/zetaspartan21/teams"
"features":"https://api.twitch.tv/kraken/channels/zetaspartan21/features"
"videos":"https://api.twitch.tv/kraken/channels/zetaspartan21/videos"
"self":"https://api.twitch.tv/kraken/channels/zetaspartan21"
"follows":"https://api.twitch.tv/kraken/channels/zetaspartan21/follows"
"chat":"https://api.twitch.tv/kraken/chat/zetaspartan21"
"stream_key":"https://api.twitch.tv/kraken/channels/zetaspartan21/stream_key"}
"name":"zetaspartan21"
"delay":0
"display_name":"ZetaSpartan21"
"video_banner":"http://static-cdn.jtvnw.net/jtv_user_pictures/zetaspartan21-channel_offline_image-b20322d22543539a-640x360.jpeg"
"background":"http://static-cdn.jtvnw.net/jtv_user_pictures/zetaspartan21-channel_background_image-587bde3d4f90b293.jpeg"
"mature":true}
Initializing User Interface - JOIN
All of this is correct. Now what I want to do, is to be able to grab, for example the 'mature' tag, and it's value. So when I grab it, it would be like as simple as:
// pseudo code
if(mature /*this is a boolean */ == true){ // do stuff}
So if you don't understand, I need to split away the quotes and semicolon between the values to retrieve a Key, Value.
It's doable with the following code :
public static Map<String, Object> parseJSON (String data) throws ParseException {
if (data==null)
return null;
final Map<String, Object> ret = new HashMap<String, Object>();
data = data.trim();
if (!data.startsWith("{") || !data.endsWith("}"))
throw new ParseException("Missing '{' or '}'.", 0);
data = data.substring(1, data.length()-1);
final String [] lines = data.split("[\r\n]");
for (int i=0; i<lines.length; i++) {
String line = lines[i];
if (line.isEmpty())
continue;
line = line.trim();
if (line.indexOf(":")<0)
throw new ParseException("Missing ':'.", 0);
String key = line.substring(0, line.indexOf(":"));
String value = line.substring(line.indexOf(":")+1);
if (key.startsWith("\"") && key.endsWith("\"") && key.length()>2)
key = key.substring(1, key.length()-1);
if (value.startsWith("{"))
while (i+1<line.length() && !value.endsWith("}"))
value = value + "\n" + lines[++i].trim();
if (value.startsWith("\"") && value.endsWith("\"") && value.length()>2)
value = value.substring(1, value.length()-1);
Object mapValue = value;
if (value.startsWith("{") && value.endsWith("}"))
mapValue = parseJSON(value);
else if (value.equalsIgnoreCase("true") || value.equalsIgnoreCase("false"))
mapValue = new Boolean (value);
else {
try {
mapValue = Integer.parseInt(value);
} catch (NumberFormatException nfe) {
try {
mapValue = Long.parseLong(value);
} catch (NumberFormatException nfe2) {}
}
}
ret.put(key, mapValue);
}
return ret;
}
You can call it like that :
try {
Map<String, Object> ret = parseJSON(sb.toString());
if(((Boolean)ret.get("mature")) == true){
System.out.println("mature is true !");
}
} catch (ParseException e) {
}
But, really, you shouldn't do this, and use an already existing JSON parser, because this code will break on any complex or invalid JSON data (like a ":" in the key), and if you want to build a true JSON parser by hand, it will take you a lot more code and debugging !
This is a parser of an easy json string:
public static HashMap<String, String> parseEasyJson(String json) {
final String regex = "([^{}: ]*?):(\\{.*?\\}|\".*?\"|[^:{}\" ]*)";
json = json.replaceAll("\n", "");
Matcher m = Pattern.compile(regex).matcher(json);
HashMap<String, String> map = new HashMap<>();
while (m.find())
map.put(m.group(1), m.group(2));
return map;
}
Live Demo