JAVA Gson的使用

叁歲伎倆 2022-04-13 10:57 221阅读 0赞

<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。