JSON 和 List、Map集合结合使用

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<strong><span style="font-size:24px;color:#ff0000;">创建User类：</span></strong>

package lgson;import java.util.ArrayList;import java.util.HashMap;/* * 自定义一个User类 *  * */public class User {public int id;public String Name;public int age;public ArrayList<String> books;public HashMap<String, String> booksMap;public String email;}

<span style="font-size:24px;color:#ff0000;"><strong>测试类：</strong></span>

package lgson_get_test;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import com.google.gson.Gson;public class Get_Test{public static void main(String [] args){Gson gson = new Gson();User user = new User();user.id = 1;user.Name = "陈郑游";user.age = 22;user.email = "649954910@qq.com";System.out.println("第一次输出JSON数据：" + gson.toJson(user) + "\n");List<String> books = new ArrayList<String>();books.add("数学");          books.add("语文");          books.add("英语");          books.add("物理");          books.add("化学");          books.add("生物");  user.books=(ArrayList<String>) books;System.out.println("第二次输出JSON数据：" + gson.toJson(user));HashMap<String, String> booksMap = new HashMap<String, String>();//map.put(key, value);booksMap.put("1", "数学");          booksMap.put("2", "语文");          booksMap.put("3", "英语");          booksMap.put("4", "物理");          booksMap.put("5", "化学");          booksMap.put("6", "生物");          user.booksMap=booksMap;        System.out.println("第三次输出JSON数据：" + gson.toJson(user) + "\n");        String string = new String();//输出的字符串使用Gson转换成User对象string.format(string, User.class);System.out.println("类名：" + user.getClass());System.out.println("年龄：" + user.age);System.out.println("名字：" + user.Name);System.out.println("邮箱：" +user.email);System.out.println("books:" + user.books);System.out.println("books size :" + user.books.size());System.out.println("booksMap:" + user.booksMap);    }}

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