JSON和对象或集合间的转换

<dependency>  
    <groupId>net.sf.json-lib</groupId>  
    <artifactId>json-lib</artifactId>  
    <version>2.4</version>  
    <classifier>jdk15</classifier>  
</dependency>  

public static void main(String[] args) {
    User user = new User();  
    user.setNickname("aaaa");  
    user.setPswd("bbb");  
    List<User> userList = new ArrayList<User>();  
    userList.add(user);  
    // 对象 --> JSONObject / JSONArray  
    JSONObject jsonObject = JSONObject.fromObject(user);  
    System.out.println(jsonObject.toString());  
    JSONArray jsonArray = JSONArray.fromObject(userList);  
    System.out.println(jsonArray.toString());  
    // JSONObject --> 对象 / JSONArray --> 集合  
    User user2 = (User) JSONObject.toBean(jsonObject,User.class);  
    System.out.println(user2.getNickname());  
    User[] userArray = (User[]) JSONArray.toArray(jsonArray,User.class);  
    System.out.println(userArray.length);  
}