简单使用Java Gson,list、map、实体类转换为json数据
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2022-06-15 14:17:30
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首先导包Gson
maven:
<!-- https://mvnrepository.com/artifact/com.google.code.gson/gson --> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.8.5</version> </dependency>
gradle:
// https://mvnrepository.com/artifact/com.google.code.gson/gson implementation group: 'com.google.code.gson', name: 'gson', version: '2.8.5'
然后我做了几个简单的数据,进行转换
package it.com.stu_demo08_08;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import org.junit.Test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class Test1 {
//list-json
@Test
public void t1(){
List<Object> list =new ArrayList<Object>();
list.add(12);
list.add("aaaaa");
list.add(true);
list.add(1.25);
System.out.println("List:"+list.toString());
//list转gson
Gson gson=new Gson();
String json=gson.toJson(list);
System.out.println("json"+json);
//gson转list
List<Object> list2=gson.fromJson(json,new TypeToken<List<Object>>(){}.getType());
System.out.println("List:"+list2.toString());
}
//map-json
@Test
public void t2(){
Map<Object,Object> map=new HashMap<Object, Object>();
map.put("字符串","张山");
map.put("int",10);
map.put("boolean",false);
System.out.println("map:"+map.toString());
//map-gson
Gson gson=new Gson();
String json=gson.toJson(map);
System.out.println("json:"+json);
//gson-map
Map<Object,Object> map2=gson.fromJson(json,new TypeToken<Map<Object,Object>>(){}.getType());
System.out.println("map:"+map2);
}
//实体类-json
@Test
public void t3(){
User user=new User();
user.setId(1);
user.setUsername("张山");
System.out.println("bean:"+user);
Gson gson=new Gson();
//bean-json
String json=gson.toJson(user);
System.out.println("json:"+json);
//json-bean
User user1=gson.fromJson(json,new TypeToken<User>(){}.getType());
System.out.println("bean:"+user1);
}
}
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