jsonLib 经典文章：http://json-lib.sourceforge.net/xref-test/net/sf/json/TestJSONObject.html

// 引入相应的包

//json-lib-2.2-jdk15.jar

import net.sf.json.JSONArray;

import net.sf.json.JSONObject;

1. //把java 对象列表转换为json对象数组，并转为字符串

JSONArray array = JSONArray.fromObject(userlist);    String jsonstr = array.toString();

2.//把java对象转换成json对象，并转化为字符串

JSONObject object = JSONObject.fromObject(invite);  Log4jInit.ysulogger.debug(object.toString());

3.//把JSON字符串转换为JAVA 对象数组

String personstr = getRequest().getParameter("persons");  JSONArray json = JSONArray.fromObject(personstr);  List
    
      persons = (List
     
      )JSONArray.toCollection(json, nvoidPerson.class);
     
    

4.//把JSON字符串转换为JAVA 对象 

str = "{\"lendperson\":\"李四\",\"lendcompany\":\"有限公司\",\"checkperson\":\"李四\",  \"lenddate\":\"2010-07-19T00:00:00\",\"lendcounts\":4,\"  passports\":[{\"passportid\":\"d\",\"name\":\"李豫川\",\"passporttype\":\"K\"},  {\"passportid\":\"K9051\",\"name\":\"李平\",\"passporttype\":\"K\"},  {\"passportid\":\"K90517\",\"name\":\"袁寒梅\",\"passporttype\":\"K\"},  {\"passportid\":\"K905199\",\"name\":\"贺明\",\"passporttype\":\"K\"}]}";   JSONObject jsonobject = JSONObject.fromObject(str);  PassportLendsEntity passportlends = null;  try {   //获取一个json数组   JSONArray array = jsonobject.getJSONArray("passports");   //将json数组 转换成 List
    
     泛型   List
     
       list = new ArrayList
      
       ();   for (int i = 0; i < array.size(); i++) {               JSONObject object = (JSONObject)array.get(i);              PassPortForLendsEntity passport = (PassPortForLendsEntity)JSONObject.toBean(object,              PassPortForLendsEntity.class);            if(passport != null){             list.add(passport);            }           }   //转换PassportLendsEntity 实体类   passportlends = (PassportLendsEntity)JSONObject.toBean(jsonobject, PassportLendsEntity.class);