概念：用一个中介对象来封装一系列的对象交互。中介者使各对象不需要显示地相互引用，从而使其耦合松散，而且可以独立地改变它们之间的交互。
核心：处理多对多关系，对对象如何协作进行了抽象，集中控制
缺点：导致中介者类复杂性上升

中介者模式结构图

image.png
java代码

  1. public class MediatorTest {
  2.     public static void main(String[] args) {
  3.         ConcreteMediator concreteMediator = new ConcreteMediator();
  5.         ConcreteColleague1 concreteColleague1 = new ConcreteColleague1(concreteMediator);
  6.         ConcreteColleague2 concreteColleague2 = new ConcreteColleague2(concreteMediator);
  8.         concreteMediator.setConcreteColleague1(concreteColleague1);
  9.         concreteMediator.setConcreteColleague2(concreteColleague2);
  11.         concreteColleague1.Send();
  12.         concreteColleague2.Send();
  13.     }
  14. }
  16. //中介者
  17. public abstract class Mediator {
  18.     public  abstract  void Send(String message, Colleague colleague);
  19. }
  21. //中介者实现类
  22. public class ConcreteMediator extends Mediator{
  23.     private ConcreteColleague1 concreteColleague1;
  24.     private ConcreteColleague2 concreteColleague2;
  25.     public void setConcreteColleague1(ConcreteColleague1 concreteColleague1){
  26.         this.concreteColleague1 = concreteColleague1;
  27.     }
  28.     public  void setConcreteColleague2(ConcreteColleague2 concreteColleague2){
  29.         this.concreteColleague2 = concreteColleague2;
  30.     }
  32.     @Override
  33.     public void Send(String message, Colleague colleague) {
  34.         if (colleague == concreteColleague1){
  35.             concreteColleague2.Notify(message);
  36.         }else{
  37.             concreteColleague1.Notify(message);
  38.         }
  39.     }
  40. }
  42. //抽象同事类
  43. public abstract class Colleague {
  44.     Mediator mediator;
  45.     public Colleague(Mediator mediator){
  46.         this.mediator = mediator;
  47.     }
  49.     public abstract void Send();
  51.     public abstract void Notify(String message);
  52. }
  54. //同事1
  55. public class ConcreteColleague1 extends Colleague {
  56.     public ConcreteColleague1(Mediator mediator) {
  57.         super(mediator);
  58.     }
  60.     @Override
  61.     public void Send() {
  62.         mediator.Send("我是同事1发送的消息", this);
  63.     }
  66.     @Override
  67.     public void Notify(String message) {
  68.         System.out.println("同事1得到信息:" + message);
  69.     }
  70. }
  72. //同事2
  73. public class ConcreteColleague2 extends Colleague{
  74.     public ConcreteColleague2(Mediator mediator) {
  75.         super(mediator);
  76.     }
  78.     @Override
  79.     public void Send() {
  80.         mediator.Send("我是同事2发送的消息", this);
  81.     }
  83.     @Override
  84.     public void Notify(String message) {
  85.         System.out.println("同事2得到信息:" + message);
  86.     }
  87. }