How to serialize Json string in apex - json

I need to parse this json string to values.
"start": { "dateTime": "2013-02-02T15:00:00+05:30" }, "end": { "dateTime": "2013-02-02T16:00:00+05:30" },
The problem is I am using JSONParser in apex (salesforce).
And my class is:
public class wrapGoogleData{
public string summary{get;set;}
public string id{get;set;}
public string status;
public creator creator;
public start start;
public wrapGoogleData(string entnm,string ezid,string sta, creator c,start s){
summary= entnm;
id= ezid;
status = sta;
creator = c;
start = s;
}
}
public class creator{
public string email;
public string displayName;
public string self;
}
public class start{
public string datetimew;
}
I am able to get all the datat from this except the datetime in the above string. As datetime is a reserved keyword in apex so i am not able to give the variable name as datetime in my class.
Any suggestion !!
Json Parser code:
JSONParser parser = JSON.createParser(jsonData );
while (parser.nextToken() != null) {
// Start at the array of invoices.
if (parser.getCurrentToken() == JSONToken.START_ARRAY) {
while (parser.nextToken() != null) {
// Advance to the start object marker to
// find next invoice statement object.
if (parser.getCurrentToken() == JSONToken.START_OBJECT) {
// Read entire invoice object, including its array of line items.
wrapGoogleData inv = (wrapGoogleData)parser.readValueAs(wrapGoogleData.class);
String s = JSON.serialize(inv);
system.debug('Serialized invoice: ' + s);
// Skip the child start array and start object markers.
//parser.skipChildren();
lstwrap.put(inv.id,inv);
}
}
}
}

Similar to Kumar's answer but without using an external app.
Changing your start class was the right idea
public class start{
public string datetimew;
}
Now, just parse the JSON before you run it through the deserializer.
string newjsondata = jsonData.replace('"dateTime"','"datetimew"');
JSONParser parser = JSON.createParser(newjsondata);
while (parser.nextToken() != null) {
...
}

Use string.replace() function and replace keys named dateTime with something like dateTime__x and then you can parse using Json.deserialize if you have converted your json to apex using json to apex convertor app on heruko platform
http://json2apex.herokuapp.com/
The above link points to an app that will convert Json into apex class and then you can use Json.serialize to parse json into apex class structure.

Related

Reading JSON values from web browser?

I have a random JSON generated online and I am able to print all the values. But how do I read each array separately? For example, the below JSON contains different attributes, how do I read the string name that is an array containing 4 values.
JSON reader:
public class JsonHelper
{
public static T[] getJsonArray<T>(string json)
{
string newJson = "{ \"array\": " + json + "}";
Wrapper<T> wrapper = JsonUtility.FromJson<Wrapper<T>>(newJson);
return wrapper.array;
}
[System.Serializable]
private class Wrapper<T>
{
public T[] array;
}
}
[System.Serializable]
public class RootObject
{
public string name;
public string height;
public string mass ;
}
The below script is used to access the JSON online through RESTApi GET service. I am able to receive the whole text but how I read one single value of name or height or mass?
Script:
using UnityEngine.Networking;
using System.Linq;
using System.Linq.Expressions;
using UnityEngine.UI;
using System.IO;
public class GetData : MonoBehaviour {
// Use this for initialization
void Start () {
StartCoroutine(GetNames());
}
IEnumerator GetNames()
{
string GetNameURL = "https://swapi.co/api/people/1/?format=json";
using(UnityWebRequest www = UnityWebRequest.Get(GetNameURL))
{
// www.chunkedTransfer = false;
yield return www.Send();
if(www.isNetworkError || www.isHttpError)
{
Debug.Log(www.error);
}
else
{
if(www.isDone)
{
string jsonResult = System.Text.Encoding.UTF8.GetString(www.downloadHandler.data);
Debug.Log(jsonResult); //I am getting the result here
}
}
}
}
}
Your API call to 'https://swapi.co/api/people/1/?format=json' returns a single object, not an array.
So after you get your json, you can access name and height etc like:
if (www.isDone)
{
string jsonResult = System.Text.Encoding.UTF8.GetString(www.downloadHandler.data);
Debug.Log(jsonResult); //I am getting the result here
RootObject person = JsonUtility.FromJson<RootObject>(jsonResult);
// then you can access each property
Debug.Log(person.name);
Debug.Log(person.height);
}

How to use parsed String from JSON [duplicate]

I have the following JSON text. How can I parse it to get the values of pageName, pagePic, post_id, etc.?
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
},
"posts": [
{
"post_id": "123456789012_123456789012",
"actor_id": "1234567890",
"picOfPersonWhoPosted": "http://example.com/photo.jpg",
"nameOfPersonWhoPosted": "Jane Doe",
"message": "Sounds cool. Can't wait to see it!",
"likesCount": "2",
"comments": [],
"timeOfPost": "1234567890"
}
]
}
The org.json library is easy to use.
Just remember (while casting or using methods like getJSONObject and getJSONArray) that in JSON notation
[ … ] represents an array, so library will parse it to JSONArray
{ … } represents an object, so library will parse it to JSONObject
Example code below:
import org.json.*;
String jsonString = ... ; //assign your JSON String here
JSONObject obj = new JSONObject(jsonString);
String pageName = obj.getJSONObject("pageInfo").getString("pageName");
JSONArray arr = obj.getJSONArray("posts"); // notice that `"posts": [...]`
for (int i = 0; i < arr.length(); i++)
{
String post_id = arr.getJSONObject(i).getString("post_id");
......
}
You may find more examples from: Parse JSON in Java
Downloadable jar: http://mvnrepository.com/artifact/org.json/json
For the sake of the example lets assume you have a class Person with just a name.
private class Person {
public String name;
public Person(String name) {
this.name = name;
}
}
Google GSON (Maven)
My personal favourite as to the great JSON serialisation / de-serialisation of objects.
Gson g = new Gson();
Person person = g.fromJson("{\"name\": \"John\"}", Person.class);
System.out.println(person.name); //John
System.out.println(g.toJson(person)); // {"name":"John"}
Update
If you want to get a single attribute out you can do it easily with the Google library as well:
JsonObject jsonObject = new JsonParser().parse("{\"name\": \"John\"}").getAsJsonObject();
System.out.println(jsonObject.get("name").getAsString()); //John
Org.JSON (Maven)
If you don't need object de-serialisation but to simply get an attribute, you can try org.json (or look GSON example above!)
JSONObject obj = new JSONObject("{\"name\": \"John\"}");
System.out.println(obj.getString("name")); //John
Jackson (Maven)
ObjectMapper mapper = new ObjectMapper();
Person user = mapper.readValue("{\"name\": \"John\"}", Person.class);
System.out.println(user.name); //John
If one wants to create Java object from JSON and vice versa, use GSON or JACKSON third party jars etc.
//from object to JSON
Gson gson = new Gson();
gson.toJson(yourObject);
// from JSON to object
yourObject o = gson.fromJson(JSONString,yourObject.class);
But if one just want to parse a JSON string and get some values, (OR create a JSON string from scratch to send over wire) just use JaveEE jar which contains JsonReader, JsonArray, JsonObject etc. You may want to download the implementation of that spec like javax.json. With these two jars I am able to parse the json and use the values.
These APIs actually follow the DOM/SAX parsing model of XML.
Response response = request.get(); // REST call
JsonReader jsonReader = Json.createReader(new StringReader(response.readEntity(String.class)));
JsonArray jsonArray = jsonReader.readArray();
ListIterator l = jsonArray.listIterator();
while ( l.hasNext() ) {
JsonObject j = (JsonObject)l.next();
JsonObject ciAttr = j.getJsonObject("ciAttributes");
quick-json parser is very straightforward, flexible, very fast and customizable. Try it
Features:
Compliant with JSON specification (RFC4627)
High-Performance JSON parser
Supports Flexible/Configurable parsing approach
Configurable validation of key/value pairs of any JSON Hierarchy
Easy to use # Very small footprint
Raises developer friendly and easy to trace exceptions
Pluggable Custom Validation support - Keys/Values can be validated by configuring custom validators as and when encountered
Validating and Non-Validating parser support
Support for two types of configuration (JSON/XML) for using quick-JSON validating parser
Requires JDK 1.5
No dependency on external libraries
Support for JSON Generation through object serialisation
Support for collection type selection during parsing process
It can be used like this:
JsonParserFactory factory=JsonParserFactory.getInstance();
JSONParser parser=factory.newJsonParser();
Map jsonMap=parser.parseJson(jsonString);
You could use Google Gson.
Using this library you only need to create a model with the same JSON structure. Then the model is automatically filled in. You have to call your variables as your JSON keys, or use #SerializedName if you want to use different names.
JSON
From your example:
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
}
"posts": [
{
"post_id": "123456789012_123456789012",
"actor_id": "1234567890",
"picOfPersonWhoPosted": "http://example.com/photo.jpg",
"nameOfPersonWhoPosted": "Jane Doe",
"message": "Sounds cool. Can't wait to see it!",
"likesCount": "2",
"comments": [],
"timeOfPost": "1234567890"
}
]
}
Model
class MyModel {
private PageInfo pageInfo;
private ArrayList<Post> posts = new ArrayList<>();
}
class PageInfo {
private String pageName;
private String pagePic;
}
class Post {
private String post_id;
#SerializedName("actor_id") // <- example SerializedName
private String actorId;
private String picOfPersonWhoPosted;
private String nameOfPersonWhoPosted;
private String message;
private String likesCount;
private ArrayList<String> comments;
private String timeOfPost;
}
Parsing
Now you can parse using Gson library:
MyModel model = gson.fromJson(jsonString, MyModel.class);
Gradle import
Remember to import the library in the app Gradle file
implementation 'com.google.code.gson:gson:2.8.6' // or earlier versions
Automatic model generation
You can generate model from JSON automatically using online tools like this.
A - Explanation
You can use Jackson libraries, for binding JSON String into POJO (Plain Old Java Object) instances. POJO is simply a class with only private fields and public getter/setter methods. Jackson is going to traverse the methods (using reflection), and maps the JSON object into the POJO instance as the field names of the class fits to the field names of the JSON object.
In your JSON object, which is actually a composite object, the main object consists o two sub-objects. So, our POJO classes should have the same hierarchy. I'll call the whole JSON Object as Page object. Page object consist of a PageInfo object, and a Post object array.
So we have to create three different POJO classes;
Page Class, a composite of PageInfo Class and array of Post Instances
PageInfo Class
Posts Class
The only package I've used is Jackson ObjectMapper, what we do is binding data;
com.fasterxml.jackson.databind.ObjectMapper
The required dependencies, the jar files is listed below;
jackson-core-2.5.1.jar
jackson-databind-2.5.1.jar
jackson-annotations-2.5.0.jar
Here is the required code;
B - Main POJO Class : Page
package com.levo.jsonex.model;
public class Page {
private PageInfo pageInfo;
private Post[] posts;
public PageInfo getPageInfo() {
return pageInfo;
}
public void setPageInfo(PageInfo pageInfo) {
this.pageInfo = pageInfo;
}
public Post[] getPosts() {
return posts;
}
public void setPosts(Post[] posts) {
this.posts = posts;
}
}
C - Child POJO Class : PageInfo
package com.levo.jsonex.model;
public class PageInfo {
private String pageName;
private String pagePic;
public String getPageName() {
return pageName;
}
public void setPageName(String pageName) {
this.pageName = pageName;
}
public String getPagePic() {
return pagePic;
}
public void setPagePic(String pagePic) {
this.pagePic = pagePic;
}
}
D - Child POJO Class : Post
package com.levo.jsonex.model;
public class Post {
private String post_id;
private String actor_id;
private String picOfPersonWhoPosted;
private String nameOfPersonWhoPosted;
private String message;
private int likesCount;
private String[] comments;
private int timeOfPost;
public String getPost_id() {
return post_id;
}
public void setPost_id(String post_id) {
this.post_id = post_id;
}
public String getActor_id() {
return actor_id;
}
public void setActor_id(String actor_id) {
this.actor_id = actor_id;
}
public String getPicOfPersonWhoPosted() {
return picOfPersonWhoPosted;
}
public void setPicOfPersonWhoPosted(String picOfPersonWhoPosted) {
this.picOfPersonWhoPosted = picOfPersonWhoPosted;
}
public String getNameOfPersonWhoPosted() {
return nameOfPersonWhoPosted;
}
public void setNameOfPersonWhoPosted(String nameOfPersonWhoPosted) {
this.nameOfPersonWhoPosted = nameOfPersonWhoPosted;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public int getLikesCount() {
return likesCount;
}
public void setLikesCount(int likesCount) {
this.likesCount = likesCount;
}
public String[] getComments() {
return comments;
}
public void setComments(String[] comments) {
this.comments = comments;
}
public int getTimeOfPost() {
return timeOfPost;
}
public void setTimeOfPost(int timeOfPost) {
this.timeOfPost = timeOfPost;
}
}
E - Sample JSON File : sampleJSONFile.json
I've just copied your JSON sample into this file and put it under the project folder.
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
},
"posts": [
{
"post_id": "123456789012_123456789012",
"actor_id": "1234567890",
"picOfPersonWhoPosted": "http://example.com/photo.jpg",
"nameOfPersonWhoPosted": "Jane Doe",
"message": "Sounds cool. Can't wait to see it!",
"likesCount": "2",
"comments": [],
"timeOfPost": "1234567890"
}
]
}
F - Demo Code
package com.levo.jsonex;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.levo.jsonex.model.Page;
import com.levo.jsonex.model.PageInfo;
import com.levo.jsonex.model.Post;
public class JSONDemo {
public static void main(String[] args) {
ObjectMapper objectMapper = new ObjectMapper();
try {
Page page = objectMapper.readValue(new File("sampleJSONFile.json"), Page.class);
printParsedObject(page);
} catch (IOException e) {
e.printStackTrace();
}
}
private static void printParsedObject(Page page) {
printPageInfo(page.getPageInfo());
System.out.println();
printPosts(page.getPosts());
}
private static void printPageInfo(PageInfo pageInfo) {
System.out.println("Page Info;");
System.out.println("**********");
System.out.println("\tPage Name : " + pageInfo.getPageName());
System.out.println("\tPage Pic : " + pageInfo.getPagePic());
}
private static void printPosts(Post[] posts) {
System.out.println("Page Posts;");
System.out.println("**********");
for(Post post : posts) {
printPost(post);
}
}
private static void printPost(Post post) {
System.out.println("\tPost Id : " + post.getPost_id());
System.out.println("\tActor Id : " + post.getActor_id());
System.out.println("\tPic Of Person Who Posted : " + post.getPicOfPersonWhoPosted());
System.out.println("\tName Of Person Who Posted : " + post.getNameOfPersonWhoPosted());
System.out.println("\tMessage : " + post.getMessage());
System.out.println("\tLikes Count : " + post.getLikesCount());
System.out.println("\tComments : " + Arrays.toString(post.getComments()));
System.out.println("\tTime Of Post : " + post.getTimeOfPost());
}
}
G - Demo Output
Page Info;
****(*****
Page Name : abc
Page Pic : http://example.com/content.jpg
Page Posts;
**********
Post Id : 123456789012_123456789012
Actor Id : 1234567890
Pic Of Person Who Posted : http://example.com/photo.jpg
Name Of Person Who Posted : Jane Doe
Message : Sounds cool. Can't wait to see it!
Likes Count : 2
Comments : []
Time Of Post : 1234567890
Almost all the answers given requires a full deserialization of the JSON into a Java object before accessing the value in the property of interest. Another alternative, which does not go this route is to use JsonPATH which is like XPath for JSON and allows traversing of JSON objects.
It is a specification and the good folks at JayWay have created a Java implementation for the specification which you can find here: https://github.com/jayway/JsonPath
So basically to use it, add it to your project, eg:
<dependency>
<groupId>com.jayway.jsonpath</groupId>
<artifactId>json-path</artifactId>
<version>${version}</version>
</dependency>
and to use:
String pageName = JsonPath.read(yourJsonString, "$.pageInfo.pageName");
String pagePic = JsonPath.read(yourJsonString, "$.pageInfo.pagePic");
String post_id = JsonPath.read(yourJsonString, "$.pagePosts[0].post_id");
etc...
Check the JsonPath specification page for more information on the other ways to transverse JSON.
Use minimal-json which is very fast and easy to use.
You can parse from String obj and Stream.
Sample data:
{
"order": 4711,
"items": [
{
"name": "NE555 Timer IC",
"cat-id": "645723",
"quantity": 10,
},
{
"name": "LM358N OpAmp IC",
"cat-id": "764525",
"quantity": 2
}
]
}
Parsing:
JsonObject object = Json.parse(input).asObject();
int orders = object.get("order").asInt();
JsonArray items = object.get("items").asArray();
Creating JSON:
JsonObject user = Json.object().add("name", "Sakib").add("age", 23);
Maven:
<dependency>
<groupId>com.eclipsesource.minimal-json</groupId>
<artifactId>minimal-json</artifactId>
<version>0.9.4</version>
</dependency>
The below example shows how to read the text in the question, represented as the "jsonText" variable. This solution uses the Java EE7 javax.json API (which is mentioned in some of the other answers). The reason I've added it as a separate answer is that the following code shows how to actually access some of the values shown in the question. An implementation of the javax.json API would be required to make this code run. The full package for each of the classes required was included as I didn't want to declare "import" statements.
javax.json.JsonReader jr =
javax.json.Json.createReader(new StringReader(jsonText));
javax.json.JsonObject jo = jr.readObject();
//Read the page info.
javax.json.JsonObject pageInfo = jo.getJsonObject("pageInfo");
System.out.println(pageInfo.getString("pageName"));
//Read the posts.
javax.json.JsonArray posts = jo.getJsonArray("posts");
//Read the first post.
javax.json.JsonObject post = posts.getJsonObject(0);
//Read the post_id field.
String postId = post.getString("post_id");
Now, before anyone goes and downvotes this answer because it doesn't use GSON, org.json, Jackson, or any of the other 3rd party frameworks available, it's an example of "required code" per the question to parse the provided text. I am well aware that adherence to the current standard JSR 353 was not being considered for JDK 9 and as such the JSR 353 spec should be treated the same as any other 3rd party JSON handling implementation.
Since nobody mentioned it yet, here is a beginning of a solution using Nashorn (JavaScript runtime part of Java 8, but deprecated in Java 11).
Solution
private static final String EXTRACTOR_SCRIPT =
"var fun = function(raw) { " +
"var json = JSON.parse(raw); " +
"return [json.pageInfo.pageName, json.pageInfo.pagePic, json.posts[0].post_id];};";
public void run() throws ScriptException, NoSuchMethodException {
ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
engine.eval(EXTRACTOR_SCRIPT);
Invocable invocable = (Invocable) engine;
JSObject result = (JSObject) invocable.invokeFunction("fun", JSON);
result.values().forEach(e -> System.out.println(e));
}
Performance comparison
I wrote JSON content containing three arrays of respectively 20, 20 and 100 elements. I only want to get the 100 elements from the third array. I use the following JavaScript function to parse and get my entries.
var fun = function(raw) {JSON.parse(raw).entries};
Running the call a million times using Nashorn takes 7.5~7.8 seconds
(JSObject) invocable.invokeFunction("fun", json);
org.json takes 20~21 seconds
new JSONObject(JSON).getJSONArray("entries");
Jackson takes 6.5~7 seconds
mapper.readValue(JSON, Entries.class).getEntries();
In this case Jackson performs better than Nashorn, which performs much better than org.json.
Nashorn API is harder to use than org.json's or Jackson's. Depending on your requirements Jackson and Nashorn both can be viable solutions.
I believe the best practice should be to go through the official Java JSON API which are still work in progress.
There are many JSON libraries available in Java.
The most notorious ones are: Jackson, GSON, Genson, FastJson and org.json.
There are typically three things one should look at for choosing any library:
Performance
Ease of use (code is simple to write and legible) - that goes with features.
For mobile apps: dependency/jar size
Specifically for JSON libraries (and any serialization/deserialization libs), databinding is also usually of interest as it removes the need of writing boiler-plate code to pack/unpack the data.
For 1, see this benchmark: https://github.com/fabienrenaud/java-json-benchmark I did using JMH which compares (jackson, gson, genson, fastjson, org.json, jsonp) performance of serializers and deserializers using stream and databind APIs.
For 2, you can find numerous examples on the Internet. The benchmark above can also be used as a source of examples...
Quick takeaway of the benchmark: Jackson performs 5 to 6 times better than org.json and more than twice better than GSON.
For your particular example, the following code decodes your json with jackson:
public class MyObj {
private PageInfo pageInfo;
private List<Post> posts;
static final class PageInfo {
private String pageName;
private String pagePic;
}
static final class Post {
private String post_id;
#JsonProperty("actor_id");
private String actorId;
#JsonProperty("picOfPersonWhoPosted")
private String pictureOfPoster;
#JsonProperty("nameOfPersonWhoPosted")
private String nameOfPoster;
private String likesCount;
private List<String> comments;
private String timeOfPost;
}
private static final ObjectMapper JACKSON = new ObjectMapper();
public static void main(String[] args) throws IOException {
MyObj o = JACKSON.readValue(args[0], MyObj.class); // assumes args[0] contains your json payload provided in your question.
}
}
Let me know if you have any questions.
This blew my mind with how easy it was. You can just pass a String holding your JSON to the constructor of a JSONObject in the default org.json package.
JSONArray rootOfPage = new JSONArray(JSONString);
Done. Drops microphone.
This works with JSONObjects as well. After that, you can just look through your hierarchy of Objects using the get() methods on your objects.
In addition to other answers, I recomend this online opensource service jsonschema2pojo.org for quick generating Java classes from json or json schema for GSON, Jackson 1.x or Jackson 2.x. For example, if you have:
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
}
"posts": [
{
"post_id": "123456789012_123456789012",
"actor_id": 1234567890,
"picOfPersonWhoPosted": "http://example.com/photo.jpg",
"nameOfPersonWhoPosted": "Jane Doe",
"message": "Sounds cool. Can't wait to see it!",
"likesCount": 2,
"comments": [],
"timeOfPost": 1234567890
}
]
}
The jsonschema2pojo.org for GSON generated:
#Generated("org.jsonschema2pojo")
public class Container {
#SerializedName("pageInfo")
#Expose
public PageInfo pageInfo;
#SerializedName("posts")
#Expose
public List<Post> posts = new ArrayList<Post>();
}
#Generated("org.jsonschema2pojo")
public class PageInfo {
#SerializedName("pageName")
#Expose
public String pageName;
#SerializedName("pagePic")
#Expose
public String pagePic;
}
#Generated("org.jsonschema2pojo")
public class Post {
#SerializedName("post_id")
#Expose
public String postId;
#SerializedName("actor_id")
#Expose
public long actorId;
#SerializedName("picOfPersonWhoPosted")
#Expose
public String picOfPersonWhoPosted;
#SerializedName("nameOfPersonWhoPosted")
#Expose
public String nameOfPersonWhoPosted;
#SerializedName("message")
#Expose
public String message;
#SerializedName("likesCount")
#Expose
public long likesCount;
#SerializedName("comments")
#Expose
public List<Object> comments = new ArrayList<Object>();
#SerializedName("timeOfPost")
#Expose
public long timeOfPost;
}
If you have some Java class(say Message) representing the JSON string(jsonString), you can use Jackson JSON library with:
Message message= new ObjectMapper().readValue(jsonString, Message.class);
and from message object you can fetch any of its attribute.
Gson is easy to learn and implement, what we need to know are following two methods
toJson() – Convert Java object to JSON format
fromJson() – Convert JSON into Java object
`
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import com.google.gson.Gson;
public class GsonExample {
public static void main(String[] args) {
Gson gson = new Gson();
try {
BufferedReader br = new BufferedReader(
new FileReader("c:\\file.json"));
//convert the json string back to object
DataObject obj = gson.fromJson(br, DataObject.class);
System.out.println(obj);
} catch (IOException e) {
e.printStackTrace();
}
}
}
`
There are many open source libraries present to parse JSON content to an object or just to read JSON values. Your requirement is just to read values and parsing it to custom object. So org.json library is enough in your case.
Use org.json library to parse it and create JsonObject:
JSONObject jsonObj = new JSONObject(<jsonStr>);
Now, use this object to get your values:
String id = jsonObj.getString("pageInfo");
You can see a complete example here:
How to parse JSON in Java
You can use the Gson Library to parse the JSON string.
Gson gson = new Gson();
JsonObject jsonObject = gson.fromJson(jsonAsString, JsonObject.class);
String pageName = jsonObject.getAsJsonObject("pageInfo").get("pageName").getAsString();
String pagePic = jsonObject.getAsJsonObject("pageInfo").get("pagePic").getAsString();
String postId = jsonObject.getAsJsonArray("posts").get(0).getAsJsonObject().get("post_id").getAsString();
You can also loop through the "posts" array as so:
JsonArray posts = jsonObject.getAsJsonArray("posts");
for (JsonElement post : posts) {
String postId = post.getAsJsonObject().get("post_id").getAsString();
//do something
}
Read the following blog post, JSON in Java.
This post is a little bit old, but still I want to answer you question.
Step 1: Create a POJO class of your data.
Step 2: Now create a object using JSON.
Employee employee = null;
ObjectMapper mapper = new ObjectMapper();
try {
employee = mapper.readValue(newFile("/home/sumit/employee.json"), Employee.class);
}
catch(JsonGenerationException e) {
e.printStackTrace();
}
For further reference you can refer to the following link.
You can use Jayway JsonPath. Below is a GitHub link with source code, pom details and good documentation.
https://github.com/jayway/JsonPath
Please follow the below steps.
Step 1: Add the jayway JSON path dependency in your class path using Maven or download the JAR file and manually add it.
<dependency>
<groupId>com.jayway.jsonpath</groupId>
<artifactId>json-path</artifactId>
<version>2.2.0</version>
</dependency>
Step 2: Please save your input JSON as a file for this example. In my case I saved your JSON as sampleJson.txt. Note you missed a comma between pageInfo and posts.
Step 3: Read the JSON contents from the above file using bufferedReader and save it as String.
BufferedReader br = new BufferedReader(new FileReader("D:\\sampleJson.txt"));
StringBuilder sb = new StringBuilder();
String line = br.readLine();
while (line != null) {
sb.append(line);
sb.append(System.lineSeparator());
line = br.readLine();
}
br.close();
String jsonInput = sb.toString();
Step 4: Parse your JSON string using jayway JSON parser.
Object document = Configuration.defaultConfiguration().jsonProvider().parse(jsonInput);
Step 5: Read the details like below.
String pageName = JsonPath.read(document, "$.pageInfo.pageName");
String pagePic = JsonPath.read(document, "$.pageInfo.pagePic");
String post_id = JsonPath.read(document, "$.posts[0].post_id");
System.out.println("$.pageInfo.pageName " + pageName);
System.out.println("$.pageInfo.pagePic " + pagePic);
System.out.println("$.posts[0].post_id " + post_id);
The output will be:
$.pageInfo.pageName = abc
$.pageInfo.pagePic = http://example.com/content.jpg
$.posts[0].post_id = 123456789012_123456789012
I have JSON like this:
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
}
}
Java class
class PageInfo {
private String pageName;
private String pagePic;
// Getters and setters
}
Code for converting this JSON to a Java class.
PageInfo pageInfo = JsonPath.parse(jsonString).read("$.pageInfo", PageInfo.class);
Maven
<dependency>
<groupId>com.jayway.jsonpath</groupId>
<artifactId>json-path</artifactId>
<version>2.2.0</version>
</dependency>
Please do something like this:
JSONParser jsonParser = new JSONParser();
JSONObject obj = (JSONObject) jsonParser.parse(contentString);
String product = (String) jsonObject.get("productId");
{
"pageInfo": {
"pageName": "abc",
"pagePic": "http://example.com/content.jpg"
},
"posts": [
{
"post_id": "123456789012_123456789012",
"actor_id": "1234567890",
"picOfPersonWhoPosted": "http://example.com/photo.jpg",
"nameOfPersonWhoPosted": "Jane Doe",
"message": "Sounds cool. Can't wait to see it!",
"likesCount": "2",
"comments": [],
"timeOfPost": "1234567890"
}
]
}
Java code :
JSONObject obj = new JSONObject(responsejsonobj);
String pageName = obj.getJSONObject("pageInfo").getString("pageName");
JSONArray arr = obj.getJSONArray("posts");
for (int i = 0; i < arr.length(); i++)
{
String post_id = arr.getJSONObject(i).getString("post_id");
......etc
}
First you need to select an implementation library to do that.
The Java API for JSON Processing (JSR 353) provides portable APIs to parse, generate, transform, and query JSON using object model and streaming APIs.
The reference implementation is here: https://jsonp.java.net/
Here you can find a list of implementations of JSR 353:
What are the API that does implement JSR-353 (JSON)
And to help you decide... I found this article as well:
http://blog.takipi.com/the-ultimate-json-library-json-simple-vs-gson-vs-jackson-vs-json/
If you go for Jackson, here is a good article about conversion between JSON to/from Java using Jackson: https://www.mkyong.com/java/how-to-convert-java-object-to-from-json-jackson/
Hope it helps!
Top answers on this page use too simple examples like object with one property (e.g. {name: value}). I think that still simple but real life example can help someone.
So this is the JSON returned by Google Translate API:
{
"data":
{
"translations":
[
{
"translatedText": "Arbeit"
}
]
}
}
I want to retrieve the value of "translatedText" attribute e.g. "Arbeit" using Google's Gson.
Two possible approaches:
Retrieve just one needed attribute
String json = callToTranslateApi("work", "de");
JsonObject jsonObject = new JsonParser().parse(json).getAsJsonObject();
return jsonObject.get("data").getAsJsonObject()
.get("translations").getAsJsonArray()
.get(0).getAsJsonObject()
.get("translatedText").getAsString();
Create Java object from JSON
class ApiResponse {
Data data;
class Data {
Translation[] translations;
class Translation {
String translatedText;
}
}
}
...
Gson g = new Gson();
String json =callToTranslateApi("work", "de");
ApiResponse response = g.fromJson(json, ApiResponse.class);
return response.data.translations[0].translatedText;
If you have maven project then add below dependency or normal project add json-simple jar.
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20180813</version>
</dependency>
Write below java code for convert JSON string to JSON array.
JSONArray ja = new JSONArray(String jsonString);
Any kind of json array
steps to solve the issue.
Convert your JSON object to a java object.
You can use this link or any online tool.
Save out as a java class like Myclass.java.
Myclass obj = new Gson().fromJson(JsonStr, Myclass.class);
Using obj, you can get your values.
One can use Apache #Model annotation to create Java model classes representing structure of JSON files and use them to access various elements in the JSON tree. Unlike other solutions this one works completely without reflection and is thus suitable for environments where reflection is impossible or comes with significant overhead.
There is a sample Maven project showing the usage. First of all it defines the structure:
#Model(className="RepositoryInfo", properties = {
#Property(name = "id", type = int.class),
#Property(name = "name", type = String.class),
#Property(name = "owner", type = Owner.class),
#Property(name = "private", type = boolean.class),
})
final class RepositoryCntrl {
#Model(className = "Owner", properties = {
#Property(name = "login", type = String.class)
})
static final class OwnerCntrl {
}
}
and then it uses the generated RepositoryInfo and Owner classes to parse the provided input stream and pick certain information up while doing that:
List<RepositoryInfo> repositories = new ArrayList<>();
try (InputStream is = initializeStream(args)) {
Models.parse(CONTEXT, RepositoryInfo.class, is, repositories);
}
System.err.println("there is " + repositories.size() + " repositories");
repositories.stream().filter((repo) -> repo != null).forEach((repo) -> {
System.err.println("repository " + repo.getName() +
" is owned by " + repo.getOwner().getLogin()
);
})
That is it! In addition to that here is a live gist showing similar example together with asynchronous network communication.
jsoniter (jsoniterator) is a relatively new and simple json library, designed to be simple and fast. All you need to do to deserialize json data is
JsonIterator.deserialize(jsonData, int[].class);
where jsonData is a string of json data.
Check out the official website
for more information.
You can use JsonNode for a structured tree representation of your JSON string. It's part of the rock solid jackson library which is omnipresent.
ObjectMapper mapper = new ObjectMapper();
JsonNode yourObj = mapper.readTree("{\"k\":\"v\"}");

Using Json.NET for JSON Model Binding

I have a method being posted to via AJAX with the following header:
public JsonResult GetDocuments(string searchTerm, SortRequest sort)
The SortRequest object is defined as follows:
[DataContract]
public class SortRequest
{
[DataMember(Name = "field")]
public string Field { get; set; }
[DataMember(Name = "dir")]
public string Direction { get; set; }
}
Because of legacy code, the JSON object has the property name "dir" which doesn't directly match the C# property name. We want to use Json.NET as the model binder for JSON requests because it is able to handle this, but the problem is that the JSON coming into the model binder looks like a single object with two top level properties, "searchTerm" and "sort". The deserialization process then tries to map that entire JSON string into each method parameter which obviously fails.
I have tried looking through the now open source .NET MVC code and have not yet been able to determine how the DefaultModelBinder class handles this gracefully. The only option I can see so far is to convert every JSON action to take in a single request parameter but this doesn't seem like a good solution as the DefaultModelBinder doesn't require this.
Edit for clarification:
The JSON request string looks something like this:
{
"searchTerm": "test",
"sort": {
"field": "name",
"dir": "asc"
}
}
We are overriding the DefaultModelBinder and only using Json.NET when the request is of type application/json. Here is the relevant code:
var request = controllerContext.HttpContext.Request;
request.InputStream.Seek(0, SeekOrigin.Begin);
using (var reader = new StreamReader(request.InputStream))
{
var jsonString = reader.ReadToEnd();
result = JsonConvert.DeserializeObject(jsonString, bindingContext.ModelType);
}
The bindingContext.ModelType is going to be set to String and SortRequest for each parameter in the method, but since the above is a single JSON object, it doesn't map to either of those types and thus inside the method itself, everything is set to default values.
I think the JsonProperty attribute can be used for this as follows:
[DataContract]
public class SortRequest
{
[DataMember(Name = "field")]
[JsonProperty("field")]
public string Field { get; set; }
[DataMember(Name = "dir")]
[JsonProperty("dir")]
public string Direction { get; set; }
}
Update
Based upon the json add a binding prefix:
public JsonResult GetDocuments(string searchTerm, [Bind(Prefix="sort"] SortRequest sort)
I ended up going with a solution using the JToken.Parse method in the Json.NET library. Essentially what is happening is that we check the top level properties of the JSON object and see if there exists the current action parameter we are trying to bind to. Where this falls down is if there is overlap between the parameter name of the action and a property name of a single request being passed in. I think this is enough of an edge case to let slide as it would require only a single object be passed into an action that is expecting multiple.
Here is the modified BindModel method:
public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
object result;
if (IsJSONRequest(controllerContext))
{
var request = controllerContext.HttpContext.Request;
request.InputStream.Seek(0, SeekOrigin.Begin);
using (var reader = new StreamReader(request.InputStream))
{
var jsonString = reader.ReadToEnd();
// Only parse non-empty requests.
if (!String.IsNullOrWhiteSpace(jsonString))
{
// Parse the JSON into a generic key/value pair object.
var obj = JToken.Parse(jsonString);
// If the string parsed and there is a top level property of the same
// name as the parameter name we are looking for, use that property
// as the JSON object to de-serialize.
if (obj != null && obj.HasValues && obj[bindingContext.ModelName] != null)
{
jsonString = obj[bindingContext.ModelName].ToString();
}
}
result = JsonConvert.DeserializeObject(jsonString, bindingContext.ModelType);
}
}
else
{
result = base.BindModel(controllerContext, bindingContext);
}
return result;
}

convert class to object actionscript 3

I`m tring to covert class to json.
The class is:
package com.globalData{
public class userSite {
private var uID:int,uName:String,uSocket:int,uZone:int,uRoom:int;
public function user(ID:int,Name:String,ZoneID:int,RoomID:int,socketID:int){
uID = ID;
uName = Name;
uSocket = socketID;
uZone = ZoneID;
uRoom = RoomID;
}
public function getName():String{
return uName;
}
public function getID():int{
return uID;
}
public function getZoneID():int{
return uZone;
}
public function getRoomID():int{
return uRoom;
}
public function getSocket():int{
return uSocket;
}
}
}
Im tryed to do:
json(Object(roomVar));
But its not work (JSOn is function on the main class)
Im need to convert the class to json and send the json -> Socket
How can i do it?
There are a few issues with your code above:
It doesn't appear as though your userSite class has a constructor. Instead, you've opted to have a user function that takes in all of the initialization arguments
You're using functions where you should probably be using accessor methods, sometimes called a getter.
public function getName():String { return uName;} would become public function get name():String { return uName;}
Instead of calling getName(), you would access name as a property: instance.name
You're attempting to pass an Object to the JSON.decode method, this method expects a String. Something like "{ 'a':1, 'b':[1,2,3] }" would be an acceptable parameter. This would return an object with two properties a and b, a would contain the value 1, and b would contain an array with the elements 1, 2, and 3. What you are looking for is actually the JSON.encode method which accepts an Object and converts it to a String (which can be parsed as JSON).
I suggest you convert all of your getXYZ() functions to accessors, this will allow an instance of that class to be read as a collection of properties, which will in turn allow the JSON.encode function to create a JSON string object from it:
package com.globalData
{
public class UserSite {
private var uID:int,uName:String,uSocket:int,uZone:int,uRoom:int;
public function UserSite(ID:int,Name:String,ZoneID:int,RoomID:int,socketID:int):void{
uID = ID;
uName = Name;
uSocket = socketID;
uZone = ZoneID;
uRoom = RoomID;
}
public function get name():String{
return uName;
}
public function get ID():int{
return uID;
}
public function get zoneID():int{
return uZone;
}
public function get roomID():int{
return uRoom;
}
public function get socket():int{
return uSocket;
}
}
}
Usage:
var roomVar:UserSite = new UserSite(1, 'Name', 2, 3, 4);
trace(JSON.encode(roomVar as Object));
Output:
{"ID":1,"name":"Name","socket":4,"roomID":3,"zoneID":2}

GSON deserialization problem

I am having a deserialization problem using the GSON library.
The following is the JSON code which I try to deserialize
{"response": {
"#service": "CreateUser",
"#response-code": "100",
"#timestamp": "2010-11-27T15:52:43-08:00",
"#version": "1.0",
"error-message": "",
"responseData": {
"user-guid": "023804207971199"
}
}}
I create the following classes
public class GsonContainer {
private GsonResponse mResponse;
public GsonContainer() { }
//get & set methods
}
public class GsonResponse {
private String mService;
private String mResponseCode;
private String mTimeStamp;
private String mVersion;
private String mErrorMessage;
private GsonResponseCreateUser mResponseData;
public GsonResponse(){
}
//gets and sets method
}
public class GsonResponseCreateUser {
private String mUserGuid;
public GsonResponseCreateUser(){
}
//get and set methods
}
After calling the GSON library the data is null. Any ideas what is wrong with the classes?
Thx in advance for your help ... I assume it's something trivial ....
#user523392 said:
the member variables have to match exactly what is given in the JSON response
This is not the case.
There are a few options for specifying how Java field names map to JSON element names.
One solution that would work for the case in the original question above is to annotate the Java class members with the #SerializedName to very explicitly declare what JSON element name it maps to.
// output: [MyObject: element=value1, elementTwo=value2]
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.annotations.SerializedName;
public class Foo
{
static String jsonInput =
"{" +
"\"element\":\"value1\"," +
"\"#element-two\":\"value2\"" +
"}";
public static void main(String[] args)
{
GsonBuilder gsonBuilder = new GsonBuilder();
Gson gson = gsonBuilder.create();
MyObject object = gson.fromJson(jsonInput, MyObject.class);
System.out.println(object);
}
}
class MyObject
{
String element;
#SerializedName("#element-two")
String elementTwo;
#Override
public String toString()
{
return String.format(
"[MyObject: element=%s, elementTwo=%s]",
element, elementTwo);
}
}
Another approach is to create a custom FieldNamingStrategy to specify how Java member names are translated to JSON element names. This example would apply the same name mapping to all Java member names. This approach would not work for the original example above, because not all of the JSON element names follow the same naming pattern -- they don't all start with '#' and some use camel case naming instead of separating name parts with '-'. An instance of this FieldNamingStrategy would be used when building the Gson instance (gsonBuilder.setFieldNamingStrategy(new MyFieldNamingStrategy());).
class MyFieldNamingStrategy implements FieldNamingStrategy
{
// Translates the field name into its JSON field name representation.
#Override
public String translateName(Field field)
{
String name = field.getName();
StringBuilder translation = new StringBuilder();
translation.append('#');
for (int i = 0, length = name.length(); i < length; i++)
{
char c = name.charAt(i);
if (Character.isUpperCase(c))
{
translation.append('-');
c = Character.toLowerCase(c);
}
translation.append(c);
}
return translation.toString();
}
}
Another approach to manage how Java field names map to JSON element names is to specify a FieldNamingPolicy when building the Gson instance, e.g., gsonBuilder.setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_DASHES);. This also would not work with the original example, however, since it applies the same name mapping policy to all situations.
The JSON response above cannot be deserialized by GSON because of the special characters # and -. GSON is based on reflections and the member variables have to match exactly what is given in the JSON response.