Today we will learn how to use Gson, JSON library, to convert json to/from java object.
JSON is stand for JavaScript Object Notation
we will use gson library's two method for this purpose
1. fromJson() – Convert JSON into Java object
2. toJson() – Convert Java object to JSON format
Firstly i have create a maven project and add gson dependency in pom
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.4</version>
</dependency>
if you will create java project then download gson jar.
package com.jp.json;
public class Student {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
package com.jp.json;
import com.google.gson.Gson;
public class JSONToObject {
public static void main(String[] args) {
String json = "{\"id\":1," +
" \"name\" : \"json\" }";
System.out.println(" json string ="+json);
Gson gson = new Gson();
Student stu = gson.fromJson(json, Student.class);
System.out.println(" values of java object ");
System.out.println(" id ="+ stu.getId() +" name ="+ stu.getName());
}
}
Output:
json string ={"id":1, "name" : "json" }
values of java object
id =1 name =json
package com.jp.json;
import com.google.gson.Gson;
public class ObjectToJSON {
public static void main(String[] args) {
Student stu = new Student();
stu.setId(10);
stu.setName("java");
System.out.println(" values of java object ");
System.out.println(" id ="+ stu.getId() +" name ="+ stu.getName());
Gson gson = new Gson();
String json = gson.toJson(stu);
System.out.println(" json string ="+ json);
}
}
Output:
values of java object
id =10 name =java
json string ={"id":10,"name":"java"}
JSON is stand for JavaScript Object Notation
we will use gson library's two method for this purpose
1. fromJson() – Convert JSON into Java object
2. toJson() – Convert Java object to JSON format
Firstly i have create a maven project and add gson dependency in pom
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.4</version>
</dependency>
if you will create java project then download gson jar.
Step 1: Cretae a pojo
package com.jp.json;
public class Student {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
Step 2: Convert JSON to Java Object Gson Example
package com.jp.json;
import com.google.gson.Gson;
public class JSONToObject {
public static void main(String[] args) {
String json = "{\"id\":1," +
" \"name\" : \"json\" }";
System.out.println(" json string ="+json);
Gson gson = new Gson();
Student stu = gson.fromJson(json, Student.class);
System.out.println(" values of java object ");
System.out.println(" id ="+ stu.getId() +" name ="+ stu.getName());
}
}
Output:
json string ={"id":1, "name" : "json" }
values of java object
id =1 name =json
Step 3: convert Java Object To JSON Gson Example
package com.jp.json;
import com.google.gson.Gson;
public class ObjectToJSON {
public static void main(String[] args) {
Student stu = new Student();
stu.setId(10);
stu.setName("java");
System.out.println(" values of java object ");
System.out.println(" id ="+ stu.getId() +" name ="+ stu.getName());
Gson gson = new Gson();
String json = gson.toJson(stu);
System.out.println(" json string ="+ json);
}
}
Output:
values of java object
id =10 name =java
json string ={"id":10,"name":"java"}
