import com.alibaba.fastjson.JSONObject;
public class JsonTest {
    public static void main(String[] args) {
        // json串(以自己的为准)
        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);
    }
}
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);

    }

}