使用Gson对Json的基本操作

Gson是谷歌的一款对Json处理的工具，使用前需要引入对应的jar包下载地址

package json;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

public class GsonDemo {
	
	private static Gson gson = new Gson();
	
	//对象转Json
	public static String ClassToJson() {
		User user = new User();
		user.setId("1");
		user.setName("王二麻子");
		String json = gson.toJson(user);
		return json;
	}
	
	//Json转对象
	public static User JsonToClass() {
		String classJson = ClassToJson();
		User user = gson.fromJson(classJson, User.class);
		return user;
		
	}
	
	//List集合转Json数组
	public static String ListToJson() {
		List<User> userList = new ArrayList<>();
		userList.add(new User("1","王一麻子"));
		userList.add(new User("2","王二麻子"));
		userList.add(new User("3","王三麻子"));
		userList.add(new User("4","王四麻子"));
		userList.add(new User("5","王五麻子"));
		userList.add(new User("6","王六麻子"));
		String json = gson.toJson(userList);
		return json;
		
	}
	
	//Json转List集合
	public static List<User> JsonToList(){
		String listJson = ListToJson();
		List<User> jsonList = gson.fromJson(listJson, new TypeToken<List<User>>() {}.getType());
		return jsonList;
		
	}
	
	//Map转Json
	public static String MapToJson() {
		Map<String,User> map = new HashMap<>();
		map.put("大哥", new User("1","李狗蛋子"));
		map.put("二哥", new User("2","李猫蛋子"));
		map.put("三哥", new User("3","李竹鼠蛋子"));
		String json = gson.toJson(map);
		return json;
	}
	
	//Json转Map
	public static Map JsonToMap() {
		String mapJson = MapToJson();
		Map<String,User> jsonMap = gson.fromJson(mapJson, Map.class);
		return jsonMap;
	}

	public static void main(String[] args) {
		System.out.println(ClassToJson());//对象转Json
		System.out.println(JsonToClass());//Json转对象
		System.out.println(ListToJson());//List集合转Json数组
		JsonToList().forEach(x->System.out.println(x));//Json转List集合
		System.out.println(MapToJson());//Map转Json
		JsonToMap().forEach((x,y) -> {System.out.println(x+":"+y);});//Json转Map
	}
}

package json;

public class User {

	private String id;
	private String name;
	
	public User() {
		super();
	}
	public User(String id, String name) {
		super();
		this.id = id;
		this.name = name;
	}
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + "]";
	}
	
	
}