在SpringBoot中添加自定义增强SpringEvent事件组件

场景说明：在使用SpringBoot时，总是要添加一大堆自定义事件，实现ApplicationEvent，来实现事件发送。

这样写代码量非常大。为了方便和避免出错，封装自定义的模块，快速实现泛型中调用SpringEvent实现事件。省去配置，简化代码，增加多线程并发处理。

一、配置自定义注解和泛型事件
1、添加自定义注解来开启配置

import org.springframework.context.annotation.Import;

import java.lang.annotation.*;

/**
 * 自动启用 Spring Event事件
 */
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Import({QySpringEventConfiguration.class})
@Documented
public @interface EnableQySpringEvent {
}

2、自定义配置中，设置线程池和注入配置

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.event.SimpleApplicationEventMulticaster;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.core.task.TaskExecutor;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

/**
 * 配置，加载EventBus事件总线
 */
@Configuration
@EnableAsync // 自动开启异步处理
@Slf4j
public class QySpringEventConfiguration {

    private final ApplicationContext applicationContext;

    @Autowired
    public QySpringEventConfiguration(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    @Bean
    public QyEventService qySpringEventService() {
        log.info("<<<<<<<<<<<<<<< 注入QyEventService实现自定义事件 >>>>>>>>>>>>>>>>>>");
        return new QySpringEventServiceImpl(applicationContext);
    }

    /**
     * 指定线程池，专用于事件订阅和发布
     *
     * @return
     */
    @Bean(name = "eventTaskExecutor")
    public TaskExecutor eventTaskExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        taskExecutor.setThreadNamePrefix("qy-springEventTaskExecutor-");
        taskExecutor.setCorePoolSize(5);
        taskExecutor.setQueueCapacity(100);
        taskExecutor.setMaxPoolSize(5);
        taskExecutor.initialize();
        return taskExecutor;
    }

    /**
     * 为SpringEvent指定线程池
     * 注意beanName必须为applicationEventMulticaster；下面的源码中你将看到
     *
     * @param beanFactory
     * @return
     */
    @Bean(name = AbstractApplicationContext.APPLICATION_EVENT_MULTICASTER_BEAN_NAME)
    public SimpleApplicationEventMulticaster eventMulticaster(BeanFactory beanFactory) {
        SimpleApplicationEventMulticaster eventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
        eventMulticaster.setTaskExecutor(eventTaskExecutor());
        return eventMulticaster;
    }

}

3、定义支持泛型的事件，省去每次配置ApplicationEvent的过程

import lombok.Getter;
import lombok.Setter;
import org.springframework.context.ApplicationEvent;
import org.springframework.core.ResolvableType;
import org.springframework.core.ResolvableTypeProvider;

/**
 * 带泛型的多重使用器
 *
 * @param <T>
 */
@Setter
@Getter
public class QyEvent<T> extends ApplicationEvent implements ResolvableTypeProvider {

    private T data;

    public QyEvent(T data) {
        super(data);
        this.data = data;
    }

    public QyEvent(Object source, T data) {
        super(source);
        this.data = data;
    }

    @Override
    public ResolvableType getResolvableType() {
        return ResolvableType.forClassWithGenerics(getClass(), ResolvableType.forInstance(data));
    }
}

4、定义发送服务

/**
 * Spring内部自带的事件发布器
 */
public interface QyEventService {

    /**
     * 发布事件
     *
     * @param qyEvent
     */
    <T> void publishEvent(QyEvent<T> qyEvent);

}

5、服务实现类

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

@Component
public class QySpringEventServiceImpl implements QyEventService {

    private final ApplicationContext applicationContext;

    @Autowired
    public QySpringEventServiceImpl(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    @Override
    public <T> void publishEvent(QyEvent<T> qyEvent) {
        applicationContext.publishEvent(qyEvent);
    }
}

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二、在使用时
1、在入口处添加注解
@EnableQySpringEvent

2、使用时，在服务中添加

@Resource
QyEventService qyEventService;

测试发送消息内容：

IntStream.rangeClosed(0, 10).forEach(item -> {
    qyEventService.publishEvent(new QyEvent<>("test" + item));
});

3、添加监听器

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component;

/**
 * 事件监听处理器
 */
@Component
@Slf4j
public class QyEventListener {

    @Async // 异步实现
    @EventListener // 监听器，会自动识别类型
    public void onOperationLogEvent(QyEvent<String> event) {
        log.info("QyEvent Listener recieve message: " + event.getData());
    }
}

日志显示：

2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-1] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test5
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-3] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test3
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-2] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test4
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-4] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test6
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-1] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test7
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-4] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test1
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-4] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test8
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-1] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test9
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-4] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test2
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-2] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test0
2024-05-21 14:51:22.798  INFO 14757 --- [qy-springEventTaskExecutor-3] c.q.justtest.listener.QyEventListener    : QyEvent Listener recieve message: test10

可以发现已经实现多线程，并且并发打印出消息。

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