I am working on JSON files to compare their data. I only want to check if value of 1 json is same as of 2nd json file.
both are having same key names and order.
JSON file data looks like :
{ "ab_property": [
{
"name": "abc",
"value": "1"
},
I have solve your problem.Also you can direct match value using key instead of for loop.
import java.io.FileReader;
import java.util.Set;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
public class compareJsonFile {
public static void main(String[] args) throws Exception {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader("/home/chandrakant/Desktop/json1.json"));
Object obj1 = parser.parse(new FileReader("/home/chandrakant/Desktop/json2.json"));
JSONObject jsonObject = (JSONObject) obj;
JSONObject jsonObject1 = (JSONObject) obj1;
Set<String> s = jsonObject.keySet();
for (String str : s) {
System.out.println("key:" + str + " : value1:" + jsonObject.get(str) + ":value2:" + jsonObject1.get(str));
//compare value of json1 with json2
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
If something miss, please comment me.
JSONassert is a popular library to compare JSON objects. If the two files are identical (keys and values), it fits your use case.
An example using org.apache.commons.io.IOUtils to read the files:
String expected = IOUtils.toString(new File("/path/to/expected").toURI(), Charset.defaultCharset()));
String actual = IOUtils.toString(new File("/path/to/actual").toURI(), Charset.defaultCharset()));
JSONAssert.assertEquals(expected, actual, false);
Related
Example of my json file is
{
"collection": [
{
"trophy-name": {
"text": "swimming",
"text2": "fast swimming"
},
"length": "50m",
"pool": "outside",
"weather": "20"
}
]
}
Right now I am able to get values from lenght, pool and weather. But I am stuck on how to access the nested array nested object trophy-name.
My code is:
public class main {
public static void main(String[] args) throws FileNotFoundException, IOException, ParseException
{
JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader("...")); // json path
JSONObject jsonObject = (JSONObject) obj;
JSONArray array = (JSONArray) jsonObject.get("collection");
for (Object number : array )
{
JSONObject testObj = (JSONObject) number;
String pool = (String)testObj.get("pool");
System.out.println(testObj.get("length"));
System.out.println(pool);
System.out.println(testObj.get("weather"));
}
}
}
This is my first time experimenting with json files so I am trying to play around with it so the code is not great.
I probably have to create new object like
JSONObject trophyObj = (JSONObject) jsonObject.get("trophy-name");
And then from there I should be able to get the text with this?
String troph = (String) trophyObj.get("text");
Even if I that is correct I am not sure how to implement it into the loop or if there is better way to do the loop?
Dont mind redoing the code differently and any advice appreciated.
Yes, you are right, simply extract the JSONObject within the loop and then get the required fields.
public class main {
public static void main(String[] args) throws FileNotFoundException, IOException, ParseException
{
JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader("...")); // json path
JSONObject jsonObject = (JSONObject) obj;
JSONArray array = (JSONArray) jsonObject.get("collection");
for (Object number : array )
{
JSONObject testObj = (JSONObject) number;
String pool = (String)testObj.get("pool");
System.out.println(testObj.get("length"));
System.out.println(pool);
System.out.println(testObj.get("weather"));
JSONObject trophyObj = (JSONObject) testObj.get("trophy-name");
System.out.println((String)trophyObj.get("text"));
System.out.println((String)trophyObj.get("text2"));
}
}
}
I need to convert JSON string to Object[].
I tried with link1 and link2 and did not help me.
Code how i get JSON string:
public static String getListJsonString() {
String getListsUrl = BASE_URL + "lists";
String result = "";
try {
URL url = new URL(getListsUrl);
URLConnection urlConnection = url.openConnection();
urlConnection.setRequestProperty("Authorization", "Basic " + getAuthStringEnc());
InputStream is = urlConnection.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
int numCharsRead;
char[] charArray = new char[1024];
StringBuffer sb = new StringBuffer();
while ((numCharsRead = isr.read(charArray)) > 0) {
sb.append(charArray, 0, numCharsRead);
}
result = sb.toString();
System.out.println(result);
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
This is example of my JSON:
And after i must fill ChomboBox on this way (this is example):
Object[] lists = getLists();
for(Object list : lists){
System.out.println("fill combobox");
}
You can use Gson, TypeToken and JSONObject, example:
final static Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();
final Type objectType = new TypeToken<Object>(){}.getType();
JSONObject obj = new JSONObject(result);
Vector<Object> lists = gson.fromJson(obj.toString(), objectType);
I suggest you should be using jackson lib. I linked a great quick tutorial that I find really clear and useful.
The idea behind jackson lib is that JSON format is a stringified Object format so you should be able to map it properly to java POJOs easily. (POJO = Plain old java object, which is an object with some fields, maybe some annotations on top of your fields and finally just getters and setters).
You can auto generate Jackson annotated POJOs classes from a json string using this link : http://www.jsonschema2pojo.org/ (just select "JSON" instead of "JSON SCHEMA", and maybe tune the other parameters depending on your need).
I can feel your pain sometimes it's hard to get a quick example up and running.
This is a very simple example how you can read your json document using Jackson library. You need a minimum of jackson-annotations-x.y.z.jar, jackson-core-x.y.z.jar and jackson-databind-x.y.z.jar files in a classpath.
https://github.com/FasterXML/jackson-databind/
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.JsonNode;
public class TestJSON1 {
public static void main(String[] args) throws Exception {
ObjectMapper mapper = new ObjectMapper();
JsonNode jsonObj;
String jsonStr = "{ \"list\": [ "
+ " {\"id\":\"1\", \"name\":\"test1\"}, "
+ " {\"id\":\"2\", \"name\":\"test2\"}, "
+ " {\"id\":\"3\", \"name\":\"test3\"} "
+ "]}";
jsonObj = mapper.readTree(jsonStr);
System.out.println(jsonObj.get("list"));
JsonNode jsonArr=jsonObj.get("list");
int count=jsonArr.size();
for (int idx=0; idx<count; idx++) {
jsonObj = jsonArr.get(idx);
System.out.println( jsonObj.get("id").asText()+"="+jsonObj.get("name").asText() );
}
}
}
I'm trying to use JSON simple as part of a Java application to pull specific data from a .json file. Whenever I run the program, I get an unexpected token error message when it tries to parse.
A simplified version of the JSON file is as follows:
{"id":123,"text":"sample1","user":{"id":111,"name":"username"},"lang":"en"}
{"id":345,"text":"sample2","user":{"id":555,"name":"user2"},"lang":"en"}
My code is as follows:
public static void readJSON() {
JSONParser jsonParser = new JSONParser();
try {
FileReader reader = new FileReader(fileLocation);
JSONObject jsonObject = (JSONObject) jsonParser.parse(reader);
JSONArray jsonArray = (JSONArray) jsonObject.get("");
Iterator<?> i = jsonArray.iterator();
while (i.hasNext()) {
JSONObject obj = (JSONObject) i.next();
int tweetID = (int) obj.get("id");
String lang = (String) obj.get("lang");
}
} catch (Exception e) {
e.printStackTrace();
}
}
In this example, the line of code:
JSONObject jsonObject = (JSONObject) jsonParser.parse(reader);
throws an error due to an unexpected token at the first left brace ({) of the second JSON object (i.e, at the brace before "id":345).
How could I go about resolving this issue?
And, as a follow up, how would one also pull the information for the username in this example?
Thanks for taking the time to read through this, and for any assistance provided!
That file is an invalid JSON file, it contains an entire object on each line.
What you'll need to do is read the file line by line, and then passing each line to the parser to create a new object.
If you fix your code, you can solve unexpected token error.
public static void readJSON() {
JSONParser jsonParser = new JSONParser();
try {
FileReader reader = new FileReader(fileLocation);
//You need to fix this part
JSONArray jsonArray = (JSONArray) jsonParser.parse(reader);
Iterator<?> i = jsonArray.iterator();
while (i.hasNext()) {
JSONObject obj = (JSONObject) i.next();
int tweetID = (int) obj.get("id");
String lang = (String) obj.get("lang");
}
} catch (Exception e) {
e.printStackTrace();
}
}
You are trying to parse JSON object, and you actually have two JSON objects.
And in your code you are actually expect an array of JSON objects.
So, use the proper JSON array:
[
{"id":123,"text":"sample1","user":{"id":111,"name":"username"},"lang":"en"},
{"id":345,"text":"sample2","user":{"id":555,"name":"user2"},"lang":"en"}
]
In order to quickly check your JSON syntax, you can use some online tool.
Your JSON is indeed wrong. It actually contains 2 valid JSONs. If you want to create one valid JSON document you have to wrap your input with { and } or [ ] if this is an array or collection. Please note the comma that separates 2 different entities.
[
{"id":123,"text":"sample1","user":{"id":111,"name":"username"},"lang":"en"},
{"id":345,"text":"sample2","user":{"id":555,"name":"user2"},"lang":"en"}
]
I've a JsonArray like:
"fields" : [
{
"name":"First Name",
"id":1
},
{
"name":"Middle Name",
"id":2
},
{
"name":"Last Name",
"id":3
}
]
I want to remove second JsonObject from above JsonArray. In order to do that I' wrote following code:
JsonArray fieldsObject =jsonObject.getJsonArray("fields");
fieldsObject.remove(fieldsObject.getJsonObject(2));
But second line throws error: java.lang.UnsupportedOperationException
Is there any way, I can remove JsonObject from a JsonArray?
You can not remove element from JsonArray as it does not support remove() method:
private static final class JsonArrayImpl extends AbstractList<JsonValue> implements JsonArray {
And remove() method's implementation comes from AbstractList :
public E remove(int index) {
throw new UnsupportedOperationException();
}
Instead why don't you create a separate data strucure array or list to hold the objects that you want?
By the way, the purpose of using JsonArray is to load json data in object form that is why it supports read methods but does not support modifications on the loaded data structure.
May be Your JsonElement or JSONArray is null.
getJsonObject returns a JSONObject.
the remove method want int.
UnsupportedOperationException
if removing is not supported.
Try This :
JSONArray fieldsObject =jsonObject.getJsonArray("fields");
fieldsObject.remove(int index);
OR
JSONArray result = new JSONArray();
for(int i=0;i<fieldsObject.length();i++)
{
if(i!=2)
{
result.put(fieldsObject.get(i));
}
}
and assign result to original one
fieldsObject=result;
gson library
Remove works for gson library version 2.3.1
public static void main(String[] args) throws Exception {
String s = "{ \"fields\" : [ "+
" {\"name\":\"First Name\",\"id\":1},"+
"{\"name\":\"Middle Name\",\"id\":2},"+
"{\"name\":\"Last Name\",\"id\":3}"+
"]}";
JsonParser parser = new JsonParser();
JsonObject json = parser.parse(s).getAsJsonObject();
System.out.println("original object:"+json);
JsonArray fieldsObject = json.getAsJsonArray("fields");
System.out.println("Before removal :"+fieldsObject);
Object remove = fieldsObject.remove(1);
System.out.println("After removal :"+fieldsObject);
}
Output:
original object:{"fields":[{"name":"First Name","id":1},{"name":"Middle Name","id":2},{"name":"Last Name","id":3}]}
Before removal :[{"name":"First Name","id":1},{"name":"Middle Name","id":2},{"name":"Last Name","id":3}]
After removal :[{"name":"First Name","id":1},{"name":"Last Name","id":3}]
org.json library
Remove works for org.json library
public static void main(String[] args) throws Exception {
String s = "{ \"fields\" : [ "+
" {\"name\":\"First Name\",\"id\":1},"+
"{\"name\":\"Middle Name\",\"id\":2},"+
"{\"name\":\"Last Name\",\"id\":3}"+
"]}";
JSONObject json = new JSONObject(s);
System.out.println("original object:"+json);
JSONArray fieldsObject =json.getJSONArray("fields");
System.out.println("Before removal :"+fieldsObject);
Object remove = fieldsObject.remove(1);
System.out.println("After removal :"+fieldsObject);
}
Output:
original object:{"fields":[{"name":"First Name","id":1},{"name":"Middle Name","id":2},{"name":"Last Name","id":3}]}
Before removal :[{"name":"First Name","id":1},{"name":"Middle Name","id":2},{"name":"Last Name","id":3}]
After removal :[{"name":"First Name","id":1},{"name":"Last Name","id":3}]
I tried using org.json library as mentioned by Sanj in the above post. We can remove the element from JSONArray as below. I placed the json content in the .txt file and read into the String object for constructing the JSONObject. Please refer the code below.
public class App{
public static void main(String args[]) throws IOException{
BufferedReader br = new BufferedReader(new FileReader("json.txt"));
String jsonContent = "";
String jsonLine;
while((jsonLine=br.readLine())!=null){
jsonContent+=jsonLine;
}
JSONObject jObj = new JSONObject(jsonContent);
JSONArray jsonArray = jObj.getJSONArray("fields");
jsonArray.remove(1);
System.out.println(jsonArray);
}
}
I'm new in java and i have this maybe simple faculty project. I must to parse json with eclipse, so i started but without any success. I don't know how to start when i have a multiple object in json.
I started like this:
public static void main(String[] args) {
FileReader reader = new FileReader(filePath);
JSONParser jsonParser = new JSONParser();
JSONObject jsonObject = (JSONObject) jsonParser.parse(reader);
JSONArray objectArray = jsonObject.getJSONArray("product");
//JSONObject site= jsonSites.getJSONObject(1);
long elementaryProductId = (long) jsonObject[0].get("elementaryProductId");
System.out.println("The id is: " + elementaryProductId);'
And thi is my json file:
[{
"elementaryProductId":1,
"bonusMalus":30,
"deductible":500,
"comprehensive":1,
"partial":0,
"legacyPremium":130,
"product":{
"productId":2,
"garage":"true",
"constructionYear":1990,
"region":"East",
"dateOfBirthYoungest":"1983-06-22",
"objectValue":25000,
"type":"Car",
"insuredObject":{
"name":"Car",
"ownersName":"Jovana",
"mileage":300000,
"engineCapacity":120
},
"salesProduct":{
"salesProductId":3,
"currency":"EUR",
"contractStart":"2011-01-01",
"contractEnd":"2012-01-01"
},
"productType":"Car"
}
},
{
"elementaryProductId":1,
"bonusMalus":5,
"deductible":100,
"comprehensive":1,
"partial":0,
"legacyPremium":75.38,
"product":{
"productId":2,
"garage":"true",
"constructionYear":2005,
"region":"East",
"dateOfBirthYoungest":"1999-06-22",
"objectValue":30000,
"type":"Car",
"insuredObject":{
"name":"Car",
"ownersName":"Jelena",
"mileage":300000,
"engineCapacity":210
},
"salesProduct":{
"salesProductId":3,
"currency":"EUR",
"contractStart":"2013-01-01",
"contractEnd":"2014-01-01"
},
"productType":"Car"
}
}]
I got it to work with the following:
public static void main(String[] args) throws IOException, ParseException{
FileReader reader = new FileReader(new File("filename.json"));
JSONParser jsonParser = new JSONParser();
JSONArray jsonArray = (JSONArray) jsonParser.parse(reader);
JSONObject object = (JSONObject) jsonArray.get(0);
long elementaryProductId = (Long) object.get("elementaryProductId");
System.out.println("The id is: " + elementaryProductId);
}
Explanation of the above:
You know the outermost element is an array so parse straight into a JSONArray. Next you want to pull out the first element of that array which is a JSONObject (its in braces). After that the code should be fairly self explanatory :)