中介者模式的核心逻辑就是解耦对象‘多对多’的相互依赖关系。当遇到一大堆混乱的对象呈现“网状结构”，利用通过中介者模式解耦对象之间的通讯。

代码案例

抽象中介类

public abstract class AbstractChatRoom {public abstract void notice(String message , User user); //声明notice方法public abstract void register(User user);
}

实现中介类

package com.example.dyc.mymedia;import java.util.ArrayList;
import java.util.List;public class ChatRoom extends AbstractChatRoom {  //继承AbstractChatRoompublic List<User> users = new ArrayList<>();  //声明列表类存储User@Overridepublic void register(User user){   //登录添加用户users.add(user);}@Overridepublic void notice(String message,User user){  //notice方法的重写for(User u : users){   //遍历if(u != user){u.getMessage(message);}}}
}

User

package com.example.dyc.mymedia;public abstract class User {   //抽象类protected AbstractChatRoom chatRoom;  //聊天室对象public User(AbstractChatRoom chatRoom){this.chatRoom = chatRoom;this.chatRoom.register(this);}public abstract void sendMessage(String msg);  //声明发送消息的方法public abstract void getMessage(String msg);   //声明接收消息的方法
}

UserA：

package com.example.dyc.mymedia;//UserA
public class UserA extends User {private String userId;public UserA(String userId, AbstractChatRoom chatRoom) {super(chatRoom);this.userId = userId;}@Overridepublic void sendMessage(String msg){System.out.println(userId + "发送 "+msg);chatRoom.notice(msg,this);}@Overridepublic void getMessage(String msg){System.out.println(userId + "收到 "+msg );}
}

客户端

public class MyTest {public static void main(String[] args) {ChatRoom chatRoom = new ChatRoom();UserA userLi = new UserA("小李", chatRoom);UserA userWa = new UserA("小娃", chatRoom);userLi.sendMessage("我是小李");System.out.println("===================");userWa.sendMessage("我是小娃");}
}

参考资料：

Java-设计模式(中介模式实现聊天室)_使用设计模式实现聊天室要求真实实现-CSDN博客