记录一下SpringBoot自定义事件监听器的使用方法

案例源码:SpringBoot使用自定义事件监听器的demo

使用的SpringBoot2.0.x版本

<parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.0.5.RELEASE</version><relativePath/> <!-- lookup parent from repository -->
</parent>

自定义事件监听： 自定义事件 和 自定义监听两部分

自定义事件
继承自ApplicationEvent抽象类，定义自己的构造器

自定义监听
实现ApplicationListener接口，然后实现onApplicationEvent方法

首先自定义事件
ApplicationEvent抽象类

实现继承，用对象方式，新建对象

DemoUser.java

package boot.example.event.events;public class DemoUser {private String username;private String password;public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}
}

EventDemoUser.java

package boot.example.event.events;import org.springframework.context.ApplicationEvent;public class EventDemoUser extends ApplicationEvent {private final DemoUser demoUser;public EventDemoUser(Object source, DemoUser demoUser) {super(source);this.demoUser = demoUser;}public DemoUser getDemoUser() {return demoUser;}
}

ApplicationListener接口

自定义监听类
EventDemoUserListener.java

package boot.example.event.listener;import boot.example.event.events.EventDemoUser;
import org.springframework.context.ApplicationListener;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;//  将监听器装载入spring容器
@Component
//@Service
public class EventDemoUserListener implements ApplicationListener<EventDemoUser> {@Async@Overridepublic void onApplicationEvent(EventDemoUser eventDemoUser) {System.out.println("自定义事件监听器（EventDemoUserListener）收到发布的消息: " + eventDemoUser.getDemoUser().getUsername());System.out.println("自定义事件监听器（EventDemoUserListener）收到发布的消息: " + eventDemoUser.getDemoUser().getPassword());}
}

我这里使用接口的方式来触发
EventDemoUserController.java

package boot.example.event.controller;import boot.example.event.events.DemoUser;
import boot.example.event.events.EventDemo;
import boot.example.event.events.EventDemoUser;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;@RestController
@RequestMapping(value="/eventDemoUser")
public class EventDemoUserController {@Resourceprivate ApplicationContext applicationContext;@RequestMapping(value="/test1")public String test1() {DemoUser demoUser = new DemoUser();demoUser.setUsername("admin");demoUser.setPassword("123456");applicationContext.publishEvent(new EventDemoUser(this, demoUser));return "testEventDemo";}@Resourceprivate ApplicationEventPublisher applicationEventPublisher;@RequestMapping(value="/test2")public String test2() {DemoUser demoUser = new DemoUser();demoUser.setUsername("admin2");demoUser.setPassword("654321");applicationContext.publishEvent(new EventDemoUser(this, demoUser));return "testEventDemo";}}

这里使用了两种触发方式

@Resource
private ApplicationContext applicationContext;

@Resource
private ApplicationEventPublisher applicationEventPublisher;

控制台输出查看

自定义监听的几种方式

1.启动时手动向ApplicationContext中添加监听器

EventDemo.java

package boot.example.event.events;import org.springframework.context.ApplicationEvent;public class EventDemo extends ApplicationEvent {public EventDemo(Object source) {super(source);}
}

AppEventDemo.java

package boot.example.event;import boot.example.event.listener.EventDemoListener1;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.scheduling.annotation.EnableAsync;@SpringBootApplication
@EnableAsync
public class AppEventDemo {public static void main( String[] args ) {ConfigurableApplicationContext context = SpringApplication.run(AppEventDemo.class, args);// 手动向ApplicationContext中添加监听器context.addApplicationListener(new EventDemoListener1());System.out.println( "Hello World!" );}//  事件监听，自定义事件和自定义监听器类//  自定义事件：继承自ApplicationEvent抽象类，定义自己的构造器//  自定义监听：实现ApplicationListener接口，实现onApplicationEvent方法}

EventDemoListener1.java

package boot.example.event.listener;import boot.example.event.events.EventDemo;
import org.springframework.context.ApplicationListener;//  手动向ApplicationContext中添加监听器  不要@Component注解就能监听到
public class EventDemoListener1 implements ApplicationListener<EventDemo> {@Overridepublic void onApplicationEvent(EventDemo eventDemo) {Object msg = eventDemo.getSource();System.out.println("自定义事件监听器（MyEventListener1）收到发布的消息: " + msg);}
}

2.使用@Component注解自动监听

EventDemoListener2.java

package boot.example.event.listener;import boot.example.event.events.EventDemo;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;//  将监听器装载入spring容器
@Component
public class EventDemoListener2 implements ApplicationListener<EventDemo> {@Overridepublic void onApplicationEvent(EventDemo eventDemo) {Object msg = eventDemo.getSource();System.out.println("自定义事件监听器（MyEventListener2）收到发布的消息: " + msg);}
}

3.在application.properties中配置监听器,可以不用注解

EventDemoListener3.java

package boot.example.event.listener;import boot.example.event.events.EventDemo;
import org.springframework.context.ApplicationListener;//  在application.properties中配置监听器,可以不用注解
public class EventDemoListener3 implements ApplicationListener<EventDemo> {@Overridepublic void onApplicationEvent(EventDemo eventDemo) {Object msg = eventDemo.getSource();System.out.println("自定义事件监听器（MyEventListener3）收到发布的消息: " + msg);}}

application.properties配置

context.listener.classes=boot.example.event.listener.EventDemoListener3

4.通过@EventListener注解实现事件监听(使用最方便)

EventDemoListener4.java

package boot.example.event.listener;import boot.example.event.events.EventDemo;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;//  通过@EventListener注解实现事件监听
@Component
public class EventDemoListener4 {@EventListenerpublic void listener(EventDemo eventDemo) {Object msg = eventDemo.getSource();System.out.println("自定义事件监听器（MyEventListener4）收到发布的消息: " + msg);}}

触发监听

EventDemoController .java

package boot.example.event.controller;import boot.example.event.events.EventDemo;
import org.springframework.context.ApplicationContext;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;@RestController
@RequestMapping(value="/eventDemo")
public class EventDemoController {@Resourceprivate ApplicationContext applicationContext;@RequestMapping(value="/test")public String test() {applicationContext.publishEvent(new EventDemo("测试监听事件"));return "testEventDemo";}
}

控制台查看 四种方式执行默认是有先后顺序的

还有一种方式 这种方式使用更方便

DemoRole.java 和 DemoUser.java

package boot.example.event.events;public class DemoRole {private Integer roleId;private String roleName;public Integer getRoleId() {return roleId;}public void setRoleId(Integer roleId) {this.roleId = roleId;}public String getRoleName() {return roleName;}public void setRoleName(String roleName) {this.roleName = roleName;}
}

package boot.example.event.events;public class DemoUser {private String username;private String password;public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}
}

监听类EventDemoListenerMultiple.java

package boot.example.event.listener;import boot.example.event.events.DemoRole;
import boot.example.event.events.DemoUser;
import org.springframework.context.event.EventListener;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;@Component
//@Service
public class EventDemoListenerMultiple {@Async@EventListener(DemoUser.class)public void listenerDemoUser(DemoUser demoUser) {String name = demoUser.getUsername();System.out.println("listenerDemoUser---"+name);}@Async@EventListener(DemoRole.class)public void listenerDemoUser(DemoRole demoRole) {String name = demoRole.getRoleName();System.out.println("listenerDemoUser---"+name);}}

监听器触发类EventDemoMultipleController.java

package boot.example.event.controller;import boot.example.event.events.DemoRole;
import boot.example.event.events.DemoUser;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;@RestController
@RequestMapping(value="/eventDemo")
public class EventDemoMultipleController {@Resourceprivate ApplicationContext applicationContext;@RequestMapping(value="/demoUser")public String demoUser() {DemoUser demoUser = new DemoUser();demoUser.setUsername("admin");demoUser.setPassword("123456");applicationContext.publishEvent(demoUser);return "testEventDemo";}@Resourceprivate ApplicationEventPublisher applicationEventPublisher;@RequestMapping(value="/demoRole")public String demoRole() {DemoRole demoRole = new DemoRole();demoRole.setRoleId(4);demoRole.setRoleName("角色");applicationContext.publishEvent(demoRole);return "testEventDemo";}}

Servlet渐渐地淡出视野，也记录一下使用

CustomServletContextListener.java

package boot.example.event.config;import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;/***  servelt的监听器*/
@WebListener
public class CustomServletContextListener implements ServletContextListener {@Overridepublic void contextInitialized(ServletContextEvent sce) {//  SpringBoot WEB启动间执行一次System.out.println("CustomServletContextListener--contextInitialized");}@Overridepublic void contextDestroyed(ServletContextEvent sce) {//  SpringBoot WEB销毁执行System.out.println("CustomServletContextListener--contextDestroyed");}}

在启动类加上扫描注解

@ServletComponentScan("boot.example.event.config")

项目结构

记录到此！