SpringBoot监听程序的启动、停止事件的方法

程序开发时，一般需要在程序启动后执行一段初始化的逻辑，在程序停止之前，执行一段“优雅终止”的逻辑。如下示例演示了在SpringBoot应用中，如何使程序在启动后或者停止前执行指定的逻辑。

1. pom.xml文件如下：

<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>syb</groupId>
    <artifactId>test</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>testpid</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
    </parent>

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

2. 程序启动事件监听器，代码如下：

package syb.test;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextRefreshedEvent;

public class StartListener implements ApplicationListener<ContextRefreshedEvent> {
    private Logger logger = LoggerFactory.getLogger(getClass());

    @Override
    public void onApplicationEvent(ContextRefreshedEvent event) {
        logger.info("程序启动");
    }

}

3. 程序停止事件监听器，代码如下：

package syb.test;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextClosedEvent;

public class CloseListener implements ApplicationListener<ContextClosedEvent> {
    private Logger logger = LoggerFactory.getLogger(getClass());
    @Override
    public void onApplicationEvent(ContextClosedEvent event) {
        logger.info("程序停止");
    }
}

4. 启动引导类代码如下，此处需要将前面的两个监听器添加到SpingApplication对象中：

package syb.test;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class App {
    public static void main(String[] args) {
        SpringApplication sa = new SpringApplication(App.class);
        sa.addListeners(new StartListener());
        sa.addListeners(new CloseListener());
        sa.run(args);
    }
}

5. 将程序打包，上传至linux系统，启动程序，可以看到打印“程序启动”，使用kill命令终止程序，可以看到打印“程序停止”。