java对象与JSON字符串互转

想完成java对象转换成JSON字符串必须在项目中导入以下jar包，缺一不可：

首先创建一个实体类Student.java

package com.zhk.bean;

public class Student {
    private String name;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString(){
        return this.name+" "+this.age;
    }
}

其次创建TestJson.java类

package com.zhk.jsontojava;

import java.util.ArrayList;
import java.util.List;

import com.zhk.bean.Student;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class TestJson {

    //java对象转为json字符串
    public static void test1(){
        Student stu = new Student();
        stu.setName("James");
        stu.setAge(35);
        JSONObject jsonobj = JSONObject.fromObject(stu);
        String jsonstr = jsonobj.toString();
        System.out.println(jsonstr);
    }

    //java数组（集合）转换为JSON字符串
    public static void test2(){
        List<Student> slist = new ArrayList<Student>();
        for(int i=0;i<3;i++){
            Student stu = new Student();
            stu.setName("zhang"+i);
            stu.setAge(20+i+1);
            slist.add(stu);
        }
        JSONArray jsonarray = JSONArray.fromObject(slist); 
        String jsonstr = jsonarray.toString();
        System.out.println(jsonstr);
    }

    //json字符串转换为java对象
    public static void test3(){
        String jsonstr = "{\"name\":\"zhang\",\"age\":15}";
        JSONObject jsonobj = JSONObject.fromObject(jsonstr);
        Student stu = (Student) JSONObject.toBean(jsonobj, Student.class);
        System.out.println(stu);
    }

    //JSON字符串转换成java数组（集合）
    public static void test4(){
        String jsonstr = "[{\"name\":\"zhang\",\"age\":15},"+
                        "{\"name\":\"zhao\",\"age\":16},"+
                        "{\"name\":\"wang\",\"age\":25}]";

        JSONArray jsonsrr = JSONArray.fromObject(jsonstr);
        List<Student> slist = (List<Student>) JSONArray.toCollection(jsonsrr, Student.class);
        for (Student student : slist) {
            System.out.println(student);
        }

    }

    public static void main(String[] args) {
        //test1();
        //test2();
        //test3();
        test4();

    }

}