How to implement custom JSON serialization with Gson in Java?

JavaJSONObject Oriented ProgrammingProgramming

A Gson library provides a way to specify custom serializers by registering a custom serializer with the GsonBuilder if we need a way to convert a java object to JSON. We can create a custom serializer by overriding the serialize() method of com.google.gson.JsonSerializer class.

In the below example, the implementation of custom serialization of JSON.

Example

import java.lang.reflect.Type;
import com.google.gson.*;
public class CustomJSONSerializerTest {
   public static void main(String[] args) {
      Gson gson = new GsonBuilder().registerTypeAdapter(Password.class, new PasswordSerializer())
.setPrettyPrinting().create();
      Student student = new Student("Adithya", "Jai", 25, "Chennai");
      student.setPassword(new Password("admin@123"));
      System.out.println(gson.toJson(student));
   }
}
class PasswordSerializer implements JsonSerializer {
   @Override
   public JsonElement serialize(Password src, Type typeOfSrc, JsonSerializationContext context) {
      return new JsonPrimitive(new StringBuffer(src.getPassword()).toString());
   }
}
// Student class
class Student {
   private String firstName;
   private String lastName;
   private int age;
   private String address;
   private Password password;
   public Student(String firstName, String lastName, int age, String address) {
      super();
      this.firstName = firstName;
      this.lastName = lastName;
      this.age = age;
      this.address = address;
   }
   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 getAddress() {
      return address;
   }
   public void setAddress(String address) {
      this.address = address;
   }
   public Password getPassword() {
      return password;
   }
   public void setPassword(Password password) {
      this.password = password;
   }
   public String toString() {
      return "Student[ " +
               "firstName = " + firstName +
               ", lastName = " + lastName +
               ", age = " + age +
               ", address = " + address +
             " ]";
   }
}
// Password class
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;
   }
}

Output

{
  "firstName": "Adithya",
  "lastName": "Jai",
  "age": 25,
 "address": "Chennai",
 "password": "admin@123"
}
raja
Published on 24-Sep-2019 14:19:37
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