JSONObject的toBean 和 fromObject

public static void main(String[] args) {
   Map map=new HashMap();
   map.put("我","妹");
   map.put("擦","哇");
   map.put("你","呀");
   JSONObject json = JSONObject.fromObject(map);
   System.out.println(json);
  }
 
輸出的結果 {"我":"妹","擦":"哇","你":"呀"}
 

 
 
toBean();
 
首先一个javabean对象
 public class Student {
 
    private int id ;
     private String name;
     private int age;
     
    public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     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 String toString(){
         return this.id + ", " + this.name + ", " + this.age;
     }
 }
 
然后测试toBean方法的类
 import net.sf.json.JSONObject;
 
public class ToBeanTest {
 
    public static void main(String[] args) {
         
        String json = "{id:'1001',name:'张三',age:'22'}";
         Student stu = new Student();
         JSONObject obj = JSONObject.fromObject(json);
         stu = (Student)JSONObject.toBean(obj, Student.class);
         System.out.println(stu);
     }
 
}
 输出结果为1001, 张三, 22 
然后我们在修改修改
 import net.sf.json.JSONObject;
 
public class ToBeanTest {
 
    public static void main(String[] args) {
         
        String json = "{id:'1001',name:'张三'}";
         Student stu = new Student();
         JSONObject obj = JSONObject.fromObject(json);
         stu = (Student)JSONObject.toBean(obj, Student.class);
         System.out.println(stu);
     }
 
}
 把年龄给去掉age为int型，输出结果为：1001, 张三, 0 
然后再做小小改动
 import net.sf.json.JSONObject;
 
public class ToBeanTest {
 
    public static void main(String[] args) {
         
        String json = "{id:'1001',age:'22'}"; 
        Student stu = new Student();
         JSONObject obj = JSONObject.fromObject(json);
         stu = (Student)JSONObject.toBean(obj, Student.class);
         System.out.println(stu);
     }
 
}
 把姓名给去掉name为String型，输出结果为：1001, null, 22 
再改动一下：
 import net.sf.json.JSONObject;
 
public class ToBeanTest {
 
    public static void main(String[] args) {
         
        String json = "{id:'1001',name:'张三',age:'nn'}";
         Student stu = new Student();
         JSONObject obj = JSONObject.fromObject(json);
         stu = (Student)JSONObject.toBean(obj, Student.class);
         System.out.println(stu);
     }
 
}
 把age改成非整形，输出结果为：
 1001, 张三, 0 

再改动一下：
 import net.sf.json.JSONObject;
 
public class ToBeanTest {
 
    public static void main(String[] args) {
         
        String json = "{id:'1001',name:'张三',age:'22',sex:'男'}";
         Student stu = new Student();
         JSONObject obj = JSONObject.fromObject(json);
         stu = (Student)JSONObject.toBean(obj, Student.class);
         System.out.println(stu);
     }
 
}
 加了一个sex:'男'的一对键值，输出结果为：
 1001, 张三, 22
 

JSONObject与JSONArray的使用方法
 


一、JAR包简介
 
      要使程序可以运行必须引入JSON-lib包，JSON-lib包同时依赖于以下的JAR包：
 
      1.commons-lang.jar
 
      2.commons-beanutils.jar
 
      3.commons-collections.jar
 
      4.commons-logging.jar 
 
      5.ezmorph.jar
 
      6.json-lib-2.2.2-jdk15.jar
 
二、JSONObject对象使用
 
     JSON-lib包是一个beans,collections,maps,java arrays 和XML和JSON互相转换的包。在本例中，我们将使用JSONObject类创建JSONObject对象，然后我们打印这些对象的值。为了使用JSONObject对象，我们要引入"net.sf.json"包。为了给对象添加元素，我们要使用put()方法。
 


package com.tjcyjd;  
 
import net.sf.json.JSONArray;
 import net.sf.json.JSONObject;
 
public class JSONObjectSample {
  // 创建JSONObject对象
  private static JSONObject createJSONObject() {
   JSONObject jsonObject = new JSONObject();
   jsonObject.put("username", "yangjinde");
   jsonObject.put("sex", "男");
   jsonObject.put("QQ", "908599713");
   jsonObject.put("yjd.score", new Integer(100));
   jsonObject.put("nickname", "搁浅");
   return jsonObject;
  }
 
 public static void main(String[] args) {
   JSONObject jsonObject = JSONObjectSample.createJSONObject();
   // 输出jsonobject对象
   System.out.println("jsonObject：" + jsonObject);
   // 判读输出对象的类型
   boolean isArray = jsonObject.isArray();
   boolean isEmpty = jsonObject.isEmpty();
   boolean isNullObject = jsonObject.isNullObject();
   System.out.println("isArray:" + isArray + " isEmpty:" + isEmpty
     + " isNullObject:" + isNullObject);
   // 往JSONObject添加属性
   jsonObject.element("address", "北京中关村");
   System.out.println("添加属性后的对象：" + jsonObject);
   // 创建一个JSONArray对象
   JSONArray jsonArray = new JSONArray();
   jsonArray.add(0, "this is a jsonArray value");
   jsonArray.add(1, "this is another jsonArray value");
   // 往JSONObject添加JSONArray
   jsonObject.element("jsonArray", jsonArray);
   JSONArray array = jsonObject.getJSONArray("jsonArray");
   System.out.println("array：" + array);
   System.out.println("添加JSONArray后的对象：" + jsonObject);
   // 根据key返回一个字符串
   String username = jsonObject.getString("username");
   System.out.println("username：" + username);
   // 把字符转换为 JSONObject
   String temp = jsonObject.toString();
   System.out.println("要转换为JSONObject的字符串为:" + temp);
   JSONObject object = JSONObject.fromObject(temp);
   // 转换后根据Key返回值
   System.out.println("qq：" + object.get("QQ"));
  }
 }
 

 
 



运行的结果如下：
 



jsonObject：{"username":"yangjinde","sex":"男","QQ":"908599713","yjd.score":100,"nickname":"搁浅"}
 isArray:false isEmpty:false isNullObject:false
 添加属性后的对象：{"username":"yangjinde","sex":"男","QQ":"908599713","yjd.score":100,"nickname":"搁浅","address":"北京中关村"}
 array：["this is a jsonArray value","this is another jsonArray value"]
 添加JSONArray后的对象：{"username":"yangjinde","sex":"男","QQ":"908599713","yjd.score":100,"nickname":"搁浅","address":"北京中关村","jsonArray":["this is a jsonArray value","this is another jsonArray value"]}
 username：yangjinde
 要转换为JSONObject的字符串为:{"username":"yangjinde","sex":"男","QQ":"908599713","yjd.score":100,"nickname":"搁浅","address":"北京中关村","jsonArray":["this is a jsonArray value","this is another jsonArray value"]}
 qq：908599713

 对象的toString方法：

@Override
 public String toString() {
  JSONObject jsonObj = JSONObject.fromObject(this);
  return jsonObj.toString();
 }

其他地方用对象.toString（）就是json