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JAVA Gson的使用

news 来源：原创 2024/4/28 14:38:01

<dependency>
          <groupId>com.google.code.gson</groupId>
          <artifactId>gson</artifactId>
          <version>2.8.2</version>
</dependency>

对数据的操作：



import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;
import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.*;

import static jdk.nashorn.internal.objects.Global.print;

/**
 * @Author : JCccc
 * @CreateTime : 2018-11-27
 * @Description :
 * @Point: Keep a good mood
 **/
public class testMain {

    public static void main(String[] args) {
     //手动创的一个实体类， 里面字段全是String类型
        User userTest=new User();
        userTest.setName("joke");
        userTest.setAge("16岁");
        userTest.setHeight("60Kg");
        userTest.setSex("男");

        Gson gson=new Gson();
        String jsonStr=gson.toJson(userTest,User.class);
        System.out.println("对象转JSON---"+jsonStr);

        User userTestNew=gson.fromJson(jsonStr,User.class);
        System.out.println("JSON转对象---"+userTestNew.toString());

       Map map=new LinkedHashMap();
       map.put("name","merry");
       map.put("age","17岁");
       map.put("height","62Kg");
       map.put("sex","女");
       String mapJsonStr=gson.toJson(map);
        System.out.println("map转JSON---"+mapJsonStr);

        List<User> userList = new ArrayList<>();
        userList.add(userTest);
       // System.out.println(userList.toString());
        String listJsonStr=gson.toJson(userList);
        System.out.println("list转JSON---"+listJsonStr);

        List<User> retList = gson.fromJson(listJsonStr,new TypeToken<List<User>>(){}.getType());
        System.out.println("listJSON转list---"+retList);

//报错
//        List<User> retList1 = gson.fromJson(mapJsonStr,new TypeToken<List<User>>(){}.getType());
//        System.out.println("mapJSON转list---"+retList1);
//报错
        /*List<User> retList2 = gson.fromJson(jsonStr,new TypeToken<List<User>>(){}.getType());
        System.out.println("对象JSON转list---"+retList2);*/
    }



}

运行结果：

对象转JSON---{"name":"joke","age":"16岁","height":"60Kg","sex":"男"}
map转JSON---{"name":"merry","age":"17岁","height":"62Kg","sex":"女"}
JSON转对象---User{name='merry', age='17岁', height='62Kg', sex='女'}
list转JSON---[{"name":"joke","age":"16岁","height":"60Kg","sex":"男"}]
listJSON转list---[User{name='joke', age='16岁', height='60Kg', sex='男'}]

好了，小记到此。