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 JSON > GOOGLE GSON > Custom Serializer

Custom Serializer 

Google-gson is a java library from Google for encoding and decoding JSON text. Get the latest binaries from http://code.google.com/p/google-gson/. The following example shows registering a custom serializer for a specific type.

File Name  :  
com/bethecoder/tutorials/google_gson/common/Student3.java 
   
package com.bethecoder.tutorials.google_gson.common;

import java.util.Date;

public class Student3 {
  private String firstName;
  private String lastName;
  private int age;
  private String hobby;
  private Date dob;
  private Password password;

  public Student3(String firstName, String lastName, int age, String hobby,
      Date dob) {
    super();
    this.firstName = firstName;
    this.lastName = lastName;
    this.age = age;
    this.hobby = hobby;
    this.dob = dob;
  }
  
  public String getFirstName() {
    return firstName;
  }
  public void setFirstName(String firstName) {
    this.firstName = firstName;
  }
  public String getLastName() {
    return lastName;
  }
  public void setLastName(String lastName) {
    this.lastName = lastName;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
  public String getHobby() {
    return hobby;
  }

  public void setHobby(String hobby) {
    this.hobby = hobby;
  }
  public Date getDob() {
    return dob;
  }
  public void setDob(Date dob) {
    this.dob = dob;
  }

  public Password getPassword() {
    return password;
  }

  public void setPassword(Password password) {
    this.password = password;
  }
  
  public String toString() {
    return "Student[ " +
      "firstName = " + firstName +
      ", lastName = " + lastName +
      ", age = " + age +
      ", hobby = " + hobby +
      ", dob = " + dob +
      " ]";
  }
}
   

File Name  :  
com/bethecoder/tutorials/google_gson/common/Password.java 
   
package com.bethecoder.tutorials.google_gson.common;

public class Password {

  private String password;

  public Password(String password) {
    super();
    this.password = password;
  }

  public String getPassword() {
    return password;
  }

  public void setPassword(String password) {
    this.password = password;
  }
}
   

File Name  :  
com/bethecoder/tutorials/google_gson/tests/CustomSerializerTest.java 
Author  :  Sudhakar KV
Email  :  [email protected]
   
package com.bethecoder.tutorials.google_gson.tests;

import java.lang.reflect.Type;
import java.util.Date;

import com.bethecoder.tutorials.google_gson.common.Password;
import com.bethecoder.tutorials.google_gson.common.Student3;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

public class CustomSerializerTest {

  /**
   * @param args
   */
  public static void main(String[] args) {
    Gson gson = new GsonBuilder()
      .registerTypeAdapter(Password.class, new PasswordSerializer()) //Register a custom
      .setPrettyPrinting().create();            //serializer for Password type.   
    
    Student3 stud = new Student3("Sriram", "Kasireddi", 2, "Singing", new Date(110, 4, 6));
    stud.setPassword(new Password("abcdefg"));
    System.out.println(gson.toJson(stud));          
  }

}

class PasswordSerializer implements JsonSerializer<Password> {

  @Override
  public JsonElement serialize(Password src, Type typeOfSrc, JsonSerializationContext context) {
    //Encrypt password using some Encryption algorithm...
    //For now this serializer reverses the password string
    return new JsonPrimitive(new StringBuffer(src.getPassword()).reverse().toString());
  }
}
   

It gives the following output, 
{
  "firstName": "Sriram",
  "lastName": "Kasireddi",
  "age": 2,
  "hobby": "Singing",
  "dob": "May 6, 2010 12:00:00 AM",
  "password": "gfedcba"
}



 
  


  
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