学会了在j2ee中使用ajax后,有时候从服务器返回客户端的数据是对象，自己手动拼凑

json字符串容易出错，通过谷歌知道了json-lib这个类库，方便的支持java中对象到json字符串的转化。

看source-forge的json-lib介绍说，需要

jakarta commons-lang 2.4

jakarta commons-beanutils 1.7.0

jakarta commons-collections 3.2

jakarta commons-logging 1.1.1

ezmorph 1.0.6

这些jar包的支持，下载下来试了一把，挺好用的，写出来，与大家分享。

代码如下：

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import net.sf.json.JSONArray;

import net.sf.json.JSONObject;

public class Test {

public static void main(String[] args) {

//当是对象的时候

Student student = new Student();

student.setAge(18);

student.setName("zhangsan");

student.setSex("male");

JSONObject jsonObject = JSONObject.fromObject(student);

System.out.println(jsonObject);//输出{"age":18,"name":"zhangsan","sex":"male"}

//当是数组或list的时候

Student[] stus = new Student[5];

List stuList = new ArrayList();

for (int i = 0; i < stus.length; i++) {

stus[i] = new Student();

stus[i].setAge(i*10+8);

stus[i].setName("zhang"+i);

stus[i].setSex("male");

//添加到list,一会儿用

stuList.add(stus[i]);

}

JSONArray jsonArray = JSONArray.fromObject(stus);

System.out.println(jsonArray);//和下面打印的结果相同

//结果：[{"age":8,"name":"zhang0","sex":"male"},{"age":18,"name":"zhang1","sex":"male"},{"age":28,"name":"zhang2","sex":"male"},{"age":38,"name":"zhang3","sex":"male"},{"age":48,"name":"zhang4","sex":"male"}]

JSONArray jsonArrayFromList = JSONArray.fromObject(stuList);

System.out.println(jsonArrayFromList);//和上面打印的结果相同

//当既有对象又有数组的时候

Map map = new HashMap();

Teacher teacher = new Teacher();

teacher.setAge(30);

teacher.setName("laoshi");

teacher.setSex("male");

map.put("teacher", teacher);

map.put("student", stuList);

JSONObject jsonObjectFromMap = JSONObject.fromObject(map);

System.out.println(jsonObjectFromMap);

//结果：

//{"student":[{"age":8,"name":"zhang0","sex":"male"},{"age":18,"name":"zhang1","sex":"male"},{"age":28,"name":"zhang2","sex":"male"},{"age":38,"name":"zhang3","sex":"male"},{"age":48,"name":"zhang4","sex":"male"}],"teacher":{"age":30,"name":"laoshi","sex":"male"}}

}

}