Tag Archives: toJson

How to do JSON pretty formatting and Null Serialization (GSON/GsonBuilder)


In previous example use GSON comes with simple JAVA API’s to convert JAVA object to/from JSON and here I will use GsonBuilder to print format JSON and serialize null object values also.

How to convert Java object to / from JSON by (GSON)

Pre-Requisite:

  • JAVA 8
  • Maven 3
  • GSON Jar as below.

GSON Dependency:

 <dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.2</version>
 </dependency>

Convert JAVA object to/from JSON

package gsonexamples;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import model.Employee;

public class GsonConvertJavaToJSON {

	public static void main(String[] args) {
		//Create GSON Object
		//Gson gson = new Gson();
Gson gson = new GsonBuilder().setPrettyPrinting().serializeNulls().create();
		Employee employee=getJavaObject();
		String json=gson.toJson(employee);

        System.out.println("Convert Java Object To JSON");
		System.out.println(json);

		System.out.println("Convert JSON To Java Object");
		employee=gson.fromJson(json,Employee.class);
		System.out.println(employee);

	}
	public static  Employee getJavaObject()
	{
		Employee employee=new Employee("C123","Saurabh" ,"Kumar","Gupta","Tech Lead",50000,"Alpharetta,GA","Dallas, TX","1231231230",null,null);
		return employee;
	}

}

  • GsonBuilder().setPrettyPrinting() :  This api is to generate pretty formatted JSON string.
  • GsonBuilder().searializeNulls() :  This api is to serialize null values in object.
  • GsonBuilder().create(): This api is to create GSON object to Java object to/from JSON.
package model;

import java.util.List;
import java.util.Set;

public class Employee {
private String employeeId;
private String firstName;
private String middleName;
private String lastName;
private String designation;
private int salary;
private String permanentAddress;
private String mailingAddress;
private String mobile;
private Set<Education> educationDetail;
private List<Experience> expericeDetail;

@Override
public String toString() {
	return "Employee [employeeId=" + employeeId + ", firstName=" + firstName + ", middleName=" + middleName
			+ ", lastName=" + lastName + ", designation=" + designation + ", salary=" + salary + ", permanentAddress="
			+ permanentAddress + ", mailingAddress=" + mailingAddress + ", mobile=" + mobile + ", educationDetail="
			+ educationDetail + ", expericeDetail=" + expericeDetail + "]";
}
public Employee(String employeeId, String firstName, String middleName, String lastName, String designation, int salary,
		String permanentAddress, String mailingAddress, String mobile, Set<Education> educationDetail,
		List<Experience> expericeDetail) {
	super();
	this.employeeId = employeeId;
	this.firstName = firstName;
	this.middleName = middleName;
	this.lastName = lastName;
	this.designation = designation;
	this.salary = salary;
	this.permanentAddress = permanentAddress;
	this.mailingAddress = mailingAddress;
	this.mobile = mobile;
	this.educationDetail = educationDetail;
	this.expericeDetail = expericeDetail;
}
//Getter and Setter
}

package model;

public class Education {
private String schoolOrCollegeName;
private String standard;
private String stream;
private double percentage;

@Override
public String toString() {
	return "Education [schoolOrCollegeName=" + schoolOrCollegeName + ", standard=" + standard + ", stream=" + stream
			+ ", percentage=" + percentage + "]";
}
public Education(String schoolOrCollegeName, String standard, String stream, double percentage) {
	super();
	this.schoolOrCollegeName = schoolOrCollegeName;
	this.standard = standard;
	this.stream = stream;
	this.percentage = percentage;
}
//getter and setter
}
package model;

import java.util.Date;

public class Experience {
private String companyName;
private String designation;
private Date startDate;
private Date endDate;
private double salary;
public Experience(String companyName, String designation, Date startDate, Date endDate, double salary) {
	super();
	this.companyName = companyName;
	this.designation = designation;
	this.startDate = startDate;
	this.endDate = endDate;
	this.salary = salary;
}
@Override
public String toString() {
	return "Experience [companyName=" + companyName + ", designation=" + designation + ", startDate=" + startDate
			+ ", endDate=" + endDate + ", salary=" + salary + "]";
}
//getter and setter
}

Output:

Convert Java Object To JSON
{
  "employeeId": "C123",
  "firstName": "Saurabh",
  "middleName": "Kumar",
  "lastName": "Gupta",
  "designation": "Tech Lead",
  "salary": 50000,
  "permanentAddress": "Alpharetta,GA",
  "mailingAddress": "Dallas, TX",
  "mobile": "1231231230",
  "educationDetail": null,
  "expericeDetail": null
}
<span 				data-mce-type="bookmark" 				id="mce_SELREST_start" 				data-mce-style="overflow:hidden;line-height:0" 				style="overflow:hidden;line-height:0" 			></span>
Convert JSON To Java Object
Employee [employeeId=C123, firstName=Saurabh, middleName=Kumar, lastName=Gupta, designation=Tech Lead, salary=50000, permanentAddress=Alpharetta,GA, mailingAddress=Dallas, TX, mobile=1231231230, educationDetail=null, expericeDetail=null]

In above JSON output is pretty formatted properly and  serialize null objects for education and experience. In next blog will explain about how to exclude fields while serializing/deserializing to/from JSON by GsonBuilder.

How to exclude fields from JSON while parsing by GSON/GsonBuilder?

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How to convert Java object to / from JSON by (GSON)


GSON comes with simple JAVA API’s toJson()/fromJson() to convert JAVA object to/from JSON. Below is very simple example to convert Employee Java object to JSON and Vice versa. To know more about GSON follow the link GSON Introduction.

Pre-Requisite:

  • JAVA 8
  • Maven 3
  • GSON Jar as below.

GSON Dependency:

 <dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.2</version>
 </dependency>

Convert JAVA object to/from JSON

package gsonexamples;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import model.Employee;

public class GsonConvertJavaToJSON {

	public static void main(String[] args) {
		//Create GSON Object
		Gson gson = new Gson();
		<span 				data-mce-type="bookmark" 				id="mce_SELREST_start" 				data-mce-style="overflow:hidden;line-height:0" 				style="overflow:hidden;line-height:0" 			></span>
		Employee employee=getJavaObject();
		String json=gson.toJson(employee);

        System.out.println("Convert Java Object To JSON");
		System.out.println(json);

		System.out.println("Convert JSON To Java Object");
		employee=gson.fromJson(json,Employee.class);
		System.out.println(employee);

	}
	public static  Employee getJavaObject()
	{
		Employee employee=new Employee("C123","Saurabh" ,"Kumar","Gupta","Tech Lead",50000,"Alpharetta,GA","Dallas, TX","1231231230",null,null);
		return employee;
	}

}

package model;

import java.util.List;
import java.util.Set;

public class Employee {
private String employeeId;
private String firstName;
private String middleName;
private String lastName;
private String designation;
private int salary;
private String permanentAddress;
private String mailingAddress;
private String mobile;
private Set<Education> educationDetail;
private List<Experience> expericeDetail;

@Override
public String toString() {
	return "Employee [employeeId=" + employeeId + ", firstName=" + firstName + ", middleName=" + middleName
			+ ", lastName=" + lastName + ", designation=" + designation + ", salary=" + salary + ", permanentAddress="
			+ permanentAddress + ", mailingAddress=" + mailingAddress + ", mobile=" + mobile + ", educationDetail="
			+ educationDetail + ", expericeDetail=" + expericeDetail + "]";
}
public Employee(String employeeId, String firstName, String middleName, String lastName, String designation, int salary,
		String permanentAddress, String mailingAddress, String mobile, Set<Education> educationDetail,
		List<Experience> expericeDetail) {
	super();
	this.employeeId = employeeId;
	this.firstName = firstName;
	this.middleName = middleName;
	this.lastName = lastName;
	this.designation = designation;
	this.salary = salary;
	this.permanentAddress = permanentAddress;
	this.mailingAddress = mailingAddress;
	this.mobile = mobile;
	this.educationDetail = educationDetail;
	this.expericeDetail = expericeDetail;
}
//Getter and Setter
}

package model;

public class Education {
private String schoolOrCollegeName;
private String standard;
private String stream;
private double percentage;

@Override
public String toString() {
	return "Education [schoolOrCollegeName=" + schoolOrCollegeName + ", standard=" + standard + ", stream=" + stream
			+ ", percentage=" + percentage + "]";
}
public Education(String schoolOrCollegeName, String standard, String stream, double percentage) {
	super();
	this.schoolOrCollegeName = schoolOrCollegeName;
	this.standard = standard;
	this.stream = stream;
	this.percentage = percentage;
}
//getter and setter
}
package model;

import java.util.Date;

public class Experience {
private String companyName;
private String designation;
private Date startDate;
private Date endDate;
private double salary;
public Experience(String companyName, String designation, Date startDate, Date endDate, double salary) {
	super();
	this.companyName = companyName;
	this.designation = designation;
	this.startDate = startDate;
	this.endDate = endDate;
	this.salary = salary;
}
@Override
public String toString() {
	return "Experience [companyName=" + companyName + ", designation=" + designation + ", startDate=" + startDate
			+ ", endDate=" + endDate + ", salary=" + salary + "]";
}
//getter and setter
}

Output:

Convert Java Object To JSON

{"employeeId":"C123","firstName":"Saurabh","middleName":"Kumar","lastName":"Gupta","designation":"Tech Lead","salary":50000,"permanentAddress":"Alpharetta,GA","mailingAddress":"Dallas, TX","mobile":"1231231230"}

Convert JSON To Java Object

Employee [employeeId=C123, firstName=Saurabh, middleName=Kumar, lastName=Gupta, designation=Tech Lead, salary=50000, permanentAddress=Alpharetta,GA, mailingAddress=Dallas, TX, mobile=1231231230, educationDetail=null, expericeDetail=null]

In above JSON output is not formatted properly and not serialize null objects for education and experience. In next blog will explain about how to format JSON and serialize null values by using GsonBuilder.

How to do JSON pretty formatting and Null Serialization (GSON/GsonBuilder)