在spring中发布订阅事件

Spring 事件机制允许在应用程序中不同的组件之间进行松耦合的通信。下面是一个简单的例子，展示如何在 Spring 中使用事件机制。

java 复制代码

import org.springframework.context.ApplicationEvent;

public class CustomEvent extends ApplicationEvent {
    private String message;

    public CustomEvent(Object source, String message) {
        super(source);
        this.message = message;
    }

    public String getMessage() {
        return message;
    }
}

java 复制代码

import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

@Component
public class CustomEventListener implements ApplicationListener<CustomEvent> {

    @Override
    public void onApplicationEvent(CustomEvent event) {
        System.out.println("Received custom event - " + event.getMessage());
    }
}

java 复制代码

import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.stereotype.Component;

@Component
public class CustomEventPublisher implements ApplicationEventPublisherAware {

    private ApplicationEventPublisher eventPublisher;

    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher 
    	applicationEventPublisher) {
        this.eventPublisher = applicationEventPublisher;
    }

    public void publishEvent(String message) {
        CustomEvent customEvent = new CustomEvent(this, message);
        eventPublisher.publishEvent(customEvent);
    }
}

java 复制代码

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class EventDemo {

    private final CustomEventPublisher customEventPublisher;

    @Autowired
    public EventDemo(CustomEventPublisher customEventPublisher) {
        this.customEventPublisher = customEventPublisher;
    }

    public void run() {
        customEventPublisher.publishEvent("Hello, Spring Event!");
    }
}