1、使用javaBean 构建json，代码演示如下：

package com.xie;

import java.util.HashMap;

import java.util.Map;

import javax.swing.plaf.synth.SynthSpinnerUI;

import com.alibaba.fastjson.*;

import com.alibaba.fastjson.JSONObject;

import org.json.*;

public class JsonTest {

     private String name ;

     private int age;

     private Boolean sex;

     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;}

     public Boolean getSex() {return sex;}

     public void setSex(Boolean sex) {this.sex = sex;}

     public static void main(String arg[]){

         JsonTest jsonTest = new JsonTest();

         jsonTest.setName("张三");

         jsonTest.setAge(20);

         jsonTest.setSex(true);

         String jsonString = creatJsonByBean(jsonTest);

         System.out.println(jsonString);

     }

     public static String creatJsonByBean(JsonTest jsonTest){

         org.json.JSONObject obj = new org.json.JSONObject(jsonTest);

         System.out.println(obj.toString());

         return obj.toString();

     }

}

2、使用HashMap穿件json，演示代码如下：

package com.xie;

import java.util.HashMap;

import java.util.Map;

import javax.swing.plaf.synth.SynthSpinnerUI;

import com.alibaba.fastjson.*;

import com.alibaba.fastjson.JSONObject;

import org.json.*;

public class JsonTest {

     public static void main(String arg[]){

         String jsonString = creatJsonByHashMap();

         System.out.println(jsonString);

     }   

    public static String creatJsonByHashMap(){

         Map map = new HashMap();

         map.put("name", null);

         map.put("age", 18);

         map.put("sex", false);

         JSONObject obj = new JSONObject(map);

         return obj.toString();

     }

}

3、一般创建json

public static String creatJson(){

     JSONObject obj = new JSONObject();

     obj.put("name","王五");

     obj.put("age", 19);

     obj.put("sex", true);

     System.out.println(obj.toString());

     return obj.toString();

}