Spring 事件驱动 @EventListener & ApplicationEventPublisher demo

解决：

不用 MQ 在 JVM spring 内进行event 发布订阅

App.java

package demo.spevent;

import java.util.logging.Level;
import java.util.logging.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.annotation.Bean;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

@SpringBootApplication
public class App {

    private static final Logger LOG = Logger.getLogger(App.class.getName());

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

    @Bean
    public CommandLineRunner cmdRunner(ItemService s) {
        return (argv) -> {
            s.updateItem(new Item(2));
        };
    }

    @Component
    public static class L {

        @EventListener
        public void onChange(ItemStatusChangeEvent e) {
            LOG.log(Level.INFO, "onChange e:{0}", e);
        }
    }

    @Component
    public static class L2 {

        @EventListener
        public void onChange2(ItemStatusChangeEvent e) {
            LOG.log(Level.INFO, "onChange2 e:{0}", e);
        }
    }

    @Service
    public static class ItemService {

        private static final Logger LOG = Logger.getLogger(ItemService.class.getName());

        private final ApplicationEventPublisher eventPub;

        @Autowired
        public ItemService(
                ApplicationEventPublisher eventPub) {
            this.eventPub = eventPub;
        }

        public void updateItem(Item i) {
            LOG.info("updateItem ....");
            eventPub.publishEvent(new ItemStatusChangeEvent(i));
        }
    }

    public static class Item {

        public Item(int status) {
            this.status = status;
        }

        int status;

        public int getStatus() {
            return status;
        }

        public void setStatus(int status) {
            this.status = status;
        }

        @Override
        public String toString() {
            return "Item{" + "status=" + status + '}';
        }

    }

    public static class ItemStatusChangeEvent {

        private final Item item;

        public ItemStatusChangeEvent(Item i) {
            this.item = i;
        }

        @Override
        public String toString() {
            return "ItemStatusChangeEvent{" + "item=" + item + '}';
        }

    }

}

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package demo.spevent;

import java.util.logging.Level;

import java.util.logging.Logger;

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

import org.springframework.boot.CommandLineRunner;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.context.ApplicationEventPublisher;

import org.springframework.context.annotation.Bean;

import org.springframework.context.event.EventListener;

import org.springframework.stereotype.Component;

import org.springframework.stereotype.Service;

@SpringBootApplication

public class App {

private static final Logger LOG = Logger.getLogger(App.class.getName());

public static void main(String[] argv) {

SpringApplication.run(App.class, argv);

}

@Bean

public CommandLineRunner cmdRunner(ItemService s) {

return (argv) -> {

s.updateItem(new Item(2));

};

}

@Component

public static class L {

@EventListener

public void onChange(ItemStatusChangeEvent e) {

LOG.log(Level.INFO, "onChange e:{0}", e);

}

@Component

public static class L2 {

@EventListener

public void onChange2(ItemStatusChangeEvent e) {

LOG.log(Level.INFO, "onChange2 e:{0}", e);

}

@Service

public static class ItemService {

private static final Logger LOG = Logger.getLogger(ItemService.class.getName());

private final ApplicationEventPublisher eventPub;

@Autowired

public ItemService(

ApplicationEventPublisher eventPub) {

this.eventPub = eventPub;

}

public void updateItem(Item i) {

LOG.info("updateItem ....");

eventPub.publishEvent(new ItemStatusChangeEvent(i));

}

public static class Item {

public Item(int status) {

this.status = status;

}

int status;

public int getStatus() {

return status;

}

public void setStatus(int status) {

this.status = status;

}

@Override

public String toString() {

return "Item{" + "status=" + status + '}';

}

public static class ItemStatusChangeEvent {

private final Item item;

public ItemStatusChangeEvent(Item i) {

this.item = i;

}

@Override

public String toString() {

return "ItemStatusChangeEvent{" + "item=" + item + '}';

}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>demo</groupId>
    <artifactId>spevent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-parent</artifactId>
        <version>2.0.0.RELEASE</version>        
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
    </dependencies>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>
</project>

<?xml version="1.0" encoding="UTF-8"?>

<artifactId>spevent</artifactId>

<version>1.0-SNAPSHOT</version>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-parent</artifactId>

<version>2.0.0.RELEASE</version>

</parent>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter</artifactId>

</dependency>

</dependencies>

<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

<maven.compiler.source>1.8</maven.compiler.source>

<maven.compiler.target>1.8</maven.compiler.target>

</properties>

</project>

参考：

http://www.sohu.com/a/195441807_355142

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Spring 事件驱动 @EventListener & ApplicationEventPublisher demo

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