Java POJO to JSON using com.google.gson.Gson
In many daily development scenarios we come across situations where we need to convert a JAVA POJO into JSON.
There are many ways that we can use to do so. The following article shows hoe to convert a POJO class into JSON using the Google Gson API.
Step 1:
Download the Gson_2.5.jar file form the link below and place it in your build path.
http://mvnrepository.com/artifact/com.google.code.gson/gson/2.5
If you are using Maven then the dependency is
Step 2:
We will start by creating a simple Employee POJO class.
Class: Employee.java
package net.codermag.json.examples;
public class Employee {
private String name;
private String email;
private EmployeeAddress address;
public void setName(String name) {
this.name = name;
}
public void setEmail(String email) {
this.email = email;
}
public void setAddress(EmployeeAddress address) {
this.address = address;
}
}
Class: EmployeeAddress.java
package net.codermag.json.examples;
public class EmployeeAddress {
private String city;
private String state;
public void setCity(String city) {
this.city = city;
}
public void setState(String state) {
this.state = state;
}
}Now that we have the structure of the POJO ready we can now convert the Employee POJO into JSON by running the following code sample.
Class: PojoToJsonExample.java
package net.codermag.json.examples;
import com.google.gson.Gson;
public class PojoToJsonExample {
public static void main(String[] args) {
// Setting values of the Employee POJO
Employee emp1 = new Employee();
emp1.setName("John");
emp1.setEmail("John@mail.com");
EmployeeAddress address = new EmployeeAddress();
address.setCity("New York");
address.setState("USA");
emp1.setAddress(address);
// Instantiating GSON
Gson gson = new Gson();
String json = gson.toJson(emp1);
System.out.println(json);
}
}
Output:
{"name":"John","email":"John@mail.com","address":{"city":"New York","state":"USA"}}