java使用gson从json中得到json对象 java从json中取值

package com.cmbc.cms.action.addrebatchno;
import java.util.List; 
import com.alibaba.fastjson.JSONObject; 
public class Test { 
public int getId() { 
return id; 
}
public void setId(int id) { 
this.id = id; 
}
public int getNum() { 
return num; 
}
public void setNum(int num) { 
this.num = num; 
}
private int id; 
private int num; 
public static void main(String[] args) { 
// TODO Auto-generated method stub 
String str = "{\"id\":\"75\",\"shoppingCartItemList\":[{\"id\":\"407\",\"num\":\"10\"}]}"; 
JSONObject jsonObject = JSONObject.parseObject(str);
// 获取到key为shoppingCartItemList的值 
String r = jsonObject.getString("shoppingCartItemList"); 
System.out.println(r);
//取外面的id 
String id = jsonObject.getString("id"); 
System.out.println(id);
//取里面的id 
List<Test> list = JSONObject.parseArray(r,Test.class); 
int id2 = list.get(0).getId(); 
System.out.println(id2);
}
}