Create Java object from a Json String

In this post you will learn how to get a Java object from a given JSON.

Step1: Add maven dependency.

<dependency>

        <groupId>org.codehaus.jackson</groupId>

        <artifactId>jackson-mapper-asl</artifactId>

        <version>1.9.13</version>

Step2: Create a pojo model class

public class Employee

{

   private Integer id;

   private String firstName;

   public Employee(){}

   public Employee(Integer id, String name){

      this.id = id;

      this.name = name;

   }

   public Integer getId(){

      return id;

   }

   public void setId(Integer id){

      this.id = id;

   }

   public String getFirstName(){

      return name;

   }

   public void setFirstName(String name){

      this.name = name;

   }

@Override

   public String toString()

   {

      return "Employee [id=" + id + ", name=" + name "]";

   }

}

Step3: Create Java Object from Json

package com.sumit.jackson;

import java.io.File;

import java.io.IOException;

import org.codehaus.jackson.JsonGenerationException;

import org.codehaus.jackson.map.JsonMappingException;

import org.codehaus.jackson.map.ObjectMapper;

public class JSONToJavaExample

{

   public static void main(String[] args){

      Employee employee = null;

      ObjectMapper mapper = new ObjectMapper();

      try{

         employee =  mapper.readValue(new File("/home/sumit/employee.json"), 
Employee.class);

      } catch (JsonGenerationException e){

         e.printStackTrace();

      } catch (JsonMappingException e){

         e.printStackTrace();

      } catch (IOException e){

         e.printStackTrace();

      }

      System.out.println(employee);

   }

}

Output: Employee [id=1, name=Sumit Kumar]


Note: File /home/sumit/employee.json Contains following data


{"id":1,"name":"sumit kumar"}

Thanks
Sumit Kumar