java 使用json-lib 对象,String,json互转

所使用的包：

commons-beanutils.jar

commons-collections-3.1.jar

commons-lang.jar

commons-logging-1.1.3.jar

ezmorph-1.0.jar

json-lib-2.2.2-jdk15.jar

先看json和String的互转

　User.java   user对象

package test;

public class User {

    String id;
    String name;
    int age;

              //省略get set
}
    

json.java

package test;

import net.sf.json.JSONObject;

public class Json{

    public static void main(String[] args) {

        //String 转json
        String text ="{‘id‘:‘001‘,‘name‘:‘jack‘,‘age‘:22}";
        JSONObject jo =JSONObject.fromObject(text);
        System.out.println(jo.get("id") +"__"+ jo.get("name") +"___" +  jo.getInt("age"));

        //String 转对象   等于是先转成json然后转对象
        String text2="{‘id‘:‘002‘,‘name‘:‘lion‘,‘age‘:23}";
        User u1 = (User)JSONObject.toBean(JSONObject.fromObject(text2), User.class);
        System.out.println(u1.getId()+"___"+u1.getName()+"__"+u1.getAge());

        //对象转json
        User  u =new User();
        u.setId("003");
        u.setAge(25);
        u.setName("Tom");

        JSONObject jo2 =JSONObject.fromObject(u);
        System.out.println(jo2);
        System.out.println(jo2.get("name"));

    }

}

打印输出

001__jack___22
002___lion__23
{"age":25,"id":"003","name":"Tom"}
Tom

给User.java 增加一个新属性book

package test;

public class User {

    String id;
    String name;
    int age;
    Book book;

// get  set 

}

Book.java

package test;

public class Book {
    String id;
    String name;
    //get  set
}

那么把user 转成json是什么样的呢？

package test;

import net.sf.json.JSONObject;

public class Json {

    public static void main(String[] args) {

     Book book =new Book();
     book .setId("111");
     book.setName("语文");

     User u =new User();
     u.setId("002");
     u.setName("xim");
     u.setBook(book);

     JSONObject jo =JSONObject.fromObject(u);
     System.out.println(jo);

    }

}

输出打印

{"age":0,"book":{"id":"111","name":"语文"},"id":"002","name":"xim"}

互转方法与第一种相同。