SpringEvent简单应用

Spring Event 是 Spring 框架内置的事件/监听器机制，是观察者模式的一种实现。它允许一个组件（发布者）发布一个事件，而其他一个或多个组件（监听器）可以订阅并响应该事件，而发布者和监听者之间没有直接的类依赖。

实现下面的实例：工人提交了维修工单后 ①发送邮件给维修站点师傅、②如果提交的是停机维修则要修改设备为停机、③增加一个操作记录

创建一个 springboot 项目，导入 web 坐标用来实现访问接口

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
     <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

启动类中添加 @EnableAsync 注解

@SpringBootApplication
@EnableAsync
public class BootEventProjectApplication {

    public static void main(String[] args) {
        SpringApplication.run(BootEventProjectApplication.class, args);
    }

}

创建一个 dataobject 来模拟数据库的 DO

import lombok.Data;

@Data
public class WorkOrderDO {

    private String code;

    private String submitter;

    private String description;

    /**
     * 是否为停机维修
     */
    private Boolean isStop;
}

创建一个RepairOrderEvent 类继承 ApplicationEvent 类

ApplicationEvent 是Spring 框架中的一个核心类，用于实现事件驱动的应用程序。它是一个抽象类，用于发布和监听事件，是 Spring 中事件机制的基础。

import com.runbrick.event.dataobject.WorkOrderDO;
import lombok.Getter;
import lombok.ToString;
import org.springframework.context.ApplicationEvent;

@Getter
@ToString
public class RepairOrderEvent extends ApplicationEvent {

    private WorkOrderDO workOrderDO;

    public RepairOrderEvent(Object source) {
        super(source);
    }

    public RepairOrderEvent(Object source, WorkOrderDO workOrderDO) {
        super(source);
        this.workOrderDO = workOrderDO;
    }

}

实现 ①发送邮件给维修站点师傅、②如果提交的是停机维修则要修改设备为停机、③增加一个操作记录这三个 Listener 用来实现在提交报修的时候来执行这几个操作


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

/**
 * 设备停机处理监听器
 */
@Slf4j
@Component
public class ShutdownListener {

    /**
     * 通过条件判断是否执行停机处理
     * @param event
     */
    @EventListener(condition = "#event.workOrderDO.isStop == true ")
    @Async
    public void equipmentShutdown(RepairOrderEvent event) {
        log.info("[repair][设备停机处理]");
    }
}


import com.runbrick.event.event.RepairOrderEvent;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.ApplicationListener;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component;

/**
 * 发送邮件
 */
@Slf4j
@Component
public class RepairEmailListener implements ApplicationListener<RepairOrderEvent> {
    @Override
    @Async
    public void onApplicationEvent(RepairOrderEvent event) {
        log.info("[onApplicationEvent][给用户({}) 发送邮件：{}]", event.getWorkOrderDO().getSubmitter(), event.getWorkOrderDO().getDescription());
    }
}

import com.runbrick.event.event.RepairOrderEvent;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.ApplicationListener;
import org.springframework.core.annotation.Order;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component;

@Component
@Slf4j
public class LogListener implements ApplicationListener<RepairOrderEvent> {
    @Override
    @Async
    @Order(10)
    public void onApplicationEvent(RepairOrderEvent event) {
        log.info("[log][记录用户({}) 的提报逻辑]", event.getWorkOrderDO());
    }
}

注：

实现监听器有两种方式一种是直接 implements ApplicationListener 另一种是通过注解 @EventListener 的方式。这两种方式都可以，不过我更推荐使用注解的方式来实现
通过 @Order() 可以实现 Listener 顺序
通过 @EnableAsync 和 @Async 实现异步，这是最主要的内容。通过 @Async 可以实现基于内存的消息队列的功能
在 @EventListener() 增加判断条件 condition = "#event.workOrderDO.isStop == true " 。用 SpEL 表达式来决定是否执行该监听器

创建一个 Controller 用来测试数据是否是我想的那样

import com.runbrick.event.dataobject.WorkOrderDO;
import com.runbrick.event.publisher.RepairService;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/repair")
@AllArgsConstructor
@Slf4j
public class RepairController {
    private RepairService repairService;

    /**
     * 提交维修工单
     */
    @PostMapping("/submit")
    public void submit(@RequestBody WorkOrderDO workOrderDO) {
        repairService.submit(workOrderDO); // 提交工单
        log.info("[repair][提交工单成功]");
    }
}

通过 IDEA 提交测试

测试非停机

### 
POST http://localhost:18080/repair/submit
Content-Type: application/json

{
  "code": "30021",
  "submitter": "张三",
  "description": "设备出问题了",
  "isStop": false
}


2025-06-26T13:44:36.855+08:00  INFO 33352 --- [io-18080-exec-2] c.r.event.publisher.RepairService        : [repair][执行用户(WorkOrderDO(code=30021, submitter=张三, description=设备出问题了, isStop=false)) 的提报逻辑]
2025-06-26T13:44:36.857+08:00  INFO 33352 --- [io-18080-exec-2] c.r.event.controller.RepairController    : [repair][提交工单成功]
2025-06-26T13:44:36.857+08:00  INFO 33352 --- [         task-6] c.runbrick.event.listener.LogListener    : [log][记录用户(WorkOrderDO(code=30021, submitter=张三, description=设备出问题了, isStop=false)) 的提报逻辑]
2025-06-26T13:44:36.857+08:00  INFO 33352 --- [         task-7] c.r.event.listener.RepairEmailListener   : [onApplicationEvent][给用户(张三) 发送邮件：设备出问题了]
2025-06-26T17:02:37.155+08:00  INFO 33352 --- [io-18080-exec-7] c.r.event.publisher.RepairService        : [repair][执行用户(WorkOrderDO(code=30021, submitter=张三, description=设备出问题了, isStop=false)) 的提报逻辑]
2025-06-26T17:02:37.163+08:00  INFO 33352 --- [         task-8] c.runbrick.event.listener.LogListener    : [log][记录用户(WorkOrderDO(code=30021, submitter=张三, description=设备出问题了, isStop=false)) 的提报逻辑]
2025-06-26T17:02:37.163+08:00  INFO 33352 --- [         task-9] c.r.event.listener.RepairEmailListener   : [onApplicationEvent][给用户(张三) 发送邮件：设备出问题了]
2025-06-26T17:02:37.166+08:00  INFO 33352 --- [io-18080-exec-7] c.r.event.controller.RepairController    : [repair][提交工单成功]

测试停机

### 
POST http://localhost:18080/repair/submit
Content-Type: application/json

{
  "code": "30021",
  "submitter": "张三",
  "description": "设备出问题了",
  "isStop": true
}

2025-06-26T17:03:17.885+08:00  INFO 33352 --- [io-18080-exec-8] c.r.event.publisher.RepairService        : [repair][执行用户(WorkOrderDO(code=30021, submitter=张三, description=设备出问题了, isStop=true)) 的提报逻辑]
2025-06-26T17:03:17.886+08:00  INFO 33352 --- [        task-10] c.runbrick.event.listener.LogListener    : [log][记录用户(WorkOrderDO(code=30021, submitter=张三, description=设备出问题了, isStop=true)) 的提报逻辑]
2025-06-26T17:03:17.886+08:00  INFO 33352 --- [        task-11] c.r.event.listener.RepairEmailListener   : [onApplicationEvent][给用户(张三) 发送邮件：设备出问题了]
2025-06-26T17:03:17.886+08:00  INFO 33352 --- [io-18080-exec-8] c.r.event.controller.RepairController    : [repair][提交工单成功]
2025-06-26T17:03:17.887+08:00  INFO 33352 --- [        task-12] c.r.event.listener.ShutdownListener      : [repair][设备停机处理]

从这两个测试来看证明在 @EventListener() 增加判断条件 condition = "#event.workOrderDO.isStop == true " 是可以的。

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