Json and Jquery Demo

Building Project Structure :

• Download the Google GSON from this link download gson.
• Create a dynamic web project and put the gson jar file in lib folder of WEB-INF.Refer the screen shot below.

JsonDemoServlet  :

• Create a Java Servlet  to process request from client (browser) .The response type of the servlet be application/JSON.

package com.sandeep.example.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sandeep.example.servlet.object.Student;
import com.sandeep.example.servlet.object.StudentDataService;

public class JsonDemoServlet extends HttpServlet {
 
private static final long serialVersionUID = 1L;
  
    public JsonDemoServlet() {
        super();
    }
 
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  
        List  listOfStudent = StudentDataService.getStudentData();
  
       String studentJsonString = StudentDataService.cerateStaticJSON(listOfStudent);;
  
      response.setContentType("application/json");
  
        PrintWriter out = response.getWriter();
        
        out.write(studentJsonString);
      
    } 

}

Student Class

package com.sandeep.example.servlet.object;

import java.util.Date;

public class Student {

 private String nameOfStudent;

 private Date dateOfRegistration;

 private int marks;

 public String getNameOfStudent() {
  return nameOfStudent;
 }

 public void setNameOfStudent(String nameOfStudent) {
  this.nameOfStudent = nameOfStudent;
 }

 public Date getDateOfRegistration() {
  return dateOfRegistration;
 }

 public void setDateOfRegistration(Date dateOfRegistration) {
  this.dateOfRegistration = dateOfRegistration;
 }

 public int getMarks() {
  return marks;
 }

 public void setMarks(int marks) {
  this.marks = marks;
 }

}

Using this class create some student object.
Student student1=new Student();
listofstudent.add(student1);
…
…

The Student Data Service Class :-

package com.sandeep.example.servlet.object;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class StudentDataService {

 /**
  * Rturn List Of Student as POJO
  * 
  * @return
  */
 public static List getStudentData() {

  List listOfStudent = new ArrayList();

  Student sudent1 = new Student();
  Student sudent2 = new Student();

  sudent1.setNameOfStudent("Sandeep");
  sudent1.setDateOfRegistration(new Date());
  sudent1.setMarks(95);

  sudent2.setNameOfStudent("Surabhi");
  sudent2.setDateOfRegistration(new Date());
  sudent2.setMarks(65);

  listOfStudent.add(sudent1);
  listOfStudent.add(sudent2);

  return listOfStudent;

 }

 /**
  * Convert Student Java Object to JSON String
  * 
  * @param studentList
  * @return
  */
 public static String cerateStaticJSON(List studentList) {

  List list = getStudentData();

  Gson gson = new Gson();

  String json = gson.toJson(list);

  return json;

 }
}

This class provides data for our demo.

The Output :-

Accessing the Link

http://localhost:8080/JsonWebDemo/JsonDemoServlet 

gives

[{"nameOfStudent":"Sandeep","dateOfRegistration":"Nov 20, 2012 10:08:00AM",

"marks":95},{"nameOfStudent":"Surabhi","dateOfRegistration":"Nov 20, 2012 10:08:00 AM","marks":65}]

Gson gson = new Gson();   

The GSON class object converts from /to JSON.

Prettifying The JSON Output :-

The output  in the firefox screenshot is coming in a single lineThis format is ugly to read and understand.To make it beautiful we can do some changes in the code cerateStaticJSON method.

public static String cerateStaticJSON(List studentList) {

  List list = getStudentData();

  Gson gson = new GsonBuilder().setPrettyPrinting().create();

  String json = gson.toJson(list);

  return json;

 }

The Changed Output:-

[
  {
    "nameOfStudent": "Sandeep",
    "dateOfRegistration": "Nov 20, 2012 10:38:12 AM",
    "marks": 95
  },
  {
    "nameOfStudent": "Surabhi",
    "dateOfRegistration": "Nov 20, 2012 10:38:12 AM",
    "marks": 65
  }
]