观察者模式(发布-订阅 Publish/Subscribe)

参考

• https://blog.csdn.net/minyunfei6/article/details/140534620

ApplicationEventPublisher 实现事件的异步

@MapperScan("com.myf.zouding.database.mapper")
@SpringBootApplication(scanBasePackages = {"com.myf"})
public class NingJinGameStarterApplication {
    private static final int NETTY_PORT = 8084;

    public static void main(String[] args) {
        SpringApplication.run(NingJinGameStarterApplication.class, args);
        NettyServer nettyServer =new NettyServer(NETTY_PORT);
        nettyServer.start();
    }

    @Bean(name = "applicationEventMulticaster")
    public SimpleApplicationEventMulticaster simpleApplicationEventMulticaster(
            @Qualifier("eventTaskExecutor") Executor executor) {
        SimpleApplicationEventMulticaster eventMulticaster = new SimpleApplicationEventMulticaster();
        eventMulticaster.setTaskExecutor(executor);
        return eventMulticaster;
    }

    @Bean(name = "eventTaskExecutor")
    public Executor eventTaskExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(5);
        executor.setMaxPoolSize(10);
        executor.setQueueCapacity(25);
        executor.setThreadNamePrefix("event-task-");
        executor.initialize();
        return executor;
    }

}

import lombok.Getter;
import lombok.Setter;

import java.util.ArrayList;
import java.util.List;



abstract class Subject{
    private List<Observer> observers =new ArrayList<>();

    public void attach(Observer observer){
        observers.add(observer);
    }
    public void detach(Observer observer){
        observers.remove(observer);
    }

    public void notice(){
        observers.forEach(it->it.update());
    }

}
abstract class Observer{

    public abstract void update();
}
class ConcreteSubject extends Subject{
    @Getter
    @Setter
    private String name;


}
class ConcreteObserver1 extends Observer{
    private ConcreteSubject subject;
    public ConcreteObserver1(ConcreteSubject subject){
        this.subject = subject;
    }
    @Override
    public void update() {
        System.out.println("观察者ConcreteObserver1观察到，通知者"+subject.getName()+"的通知！");
    }
}
class ConcreteObserver2 extends Observer{
    private ConcreteSubject subject;
    public ConcreteObserver2(ConcreteSubject subject){
        this.subject = subject;
    }
    @Override
    public void update() {
        System.out.println("观察者ConcreteObserver2观察到，通知者"+subject.getName()+"的通知！");
    }
}
public class test {

    public static void main(String[] args) {
        ConcreteSubject concreteSubject =new ConcreteSubject();
        concreteSubject.setName("zs");
        concreteSubject.attach(new ConcreteObserver1(concreteSubject));
        concreteSubject.attach(new ConcreteObserver2(concreteSubject));
        concreteSubject.notice();
    }

}