JAVA对象转换为JSON字符串

文转自：http://yxgyh.iteye.com/blog/392657

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 

jar包下载:java2json.jar 

  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<Student> stuList = new ArrayList<Student>(); 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<String,Object> map = new HashMap<String,Object>(); 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"}} } }