程序開發時,一般需要在程序啟動后執行一段初始化的邏輯,在程序停止之前,執行一段“優雅終止”的邏輯。如下示例演示了在SpringBoot應用中,如何使程序在啟動后或者停止前執行指定的邏輯。
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. 程序啟動事件監聽器,代碼如下:
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("程序啟動"); } }
3. 程序停止事件監聽器,代碼如下:
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. 啟動引導類代碼如下,此處需要將前面的兩個監聽器添加到SpingApplication對象中:
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. 將程序打包,上傳至linux系統,啟動程序,可以看到打印“程序啟動”,使用kill命令終止程序,可以看到打印“程序停止”。