Springboot-自定义运行监听器（SpringApplicationRunListener）

最新推荐文章于 2024-09-14 10:02:06 发布

ilwoziji

最新推荐文章于 2024-09-14 10:02:06 发布

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文章标签： spring java

本文链接：https://blog.youkuaiyun.com/ilwoziji/article/details/129761431

文章展示了如何在Springboot应用中创建自定义的运行时监听器，通过实现SpringApplicationRunListener接口并配置在spring.factories文件中，监听应用程序的启动过程，包括环境准备、上下文创建等各个阶段。

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Springboot暴露了对运行时过程监听的接口，其默认实现是org.springframework.boot.context.event.EventPublishingRunListener，通过此监听器进行发布相关事件，同时开发人员也可以自定义该接口的实现。

新建maven工程

pom.xml如下

<?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">
    <parent>
        <artifactId>starter-test</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>web</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

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

</project>

自定义监听器

package org.example.listener;

import org.springframework.boot.ConfigurableBootstrapContext;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.SpringApplicationRunListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.env.ConfigurableEnvironment;

import java.time.Duration;


public class CustomizedSpringApplicationRunListener implements SpringApplicationRunListener {


    public CustomizedSpringApplicationRunListener(SpringApplication application, String[] args) {

    }

    @Override
    public void starting(ConfigurableBootstrapContext bootstrapContext) {
        System.out.println("----------CustomizedSpringApplicationRunListener.starting()");
    }

    @Override
    public void environmentPrepared(ConfigurableBootstrapContext bootstrapContext, ConfigurableEnvironment environment) {
        System.out.println("----------CustomizedSpringApplicationRunListener.environmentPrepared()");
    }

    @Override
    public void contextPrepared(ConfigurableApplicationContext context) {
        System.out.println("----------CustomizedSpringApplicationRunListener.contextPrepared()");
    }

    @Override
    public void contextLoaded(ConfigurableApplicationContext context) {
        System.out.println("----------CustomizedSpringApplicationRunListener.contextLoaded()");
    }

    @Override
    public void started(ConfigurableApplicationContext context, Duration timeTaken) {
        System.out.println("----------CustomizedSpringApplicationRunListener.started()");
    }

    @Override
    public void ready(ConfigurableApplicationContext context, Duration timeTaken) {
        System.out.println("----------CustomizedSpringApplicationRunListener.ready()");
    }

    @Override
    public void failed(ConfigurableApplicationContext context, Throwable exception) {
        System.out.println("----------CustomizedSpringApplicationRunListener.failed()");
    }
}

配置监听器

resources/META-INFO/spring.factories文件中增加自定义的运行监听器

org.springframework.boot.SpringApplicationRunListener=\
org.example.listener.CustomizedSpringApplicationRunListener

启动引导类

package org.example;

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

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

控制台输出

/Users/xiaosa/dev_tools/jdk-17.0.4.1.jdk/Contents/Home/bin/java -javaagent:/Applications/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar=51343:/Applications/IntelliJ IDEA CE.app/Contents/bin -Dfile.encoding=UTF-8 -classpath /Users/xiaosa/idea_project/starter-test/web/target/classes:/Users/xiaosa/.m2/repository/org/springframework/boot/spring-boot-starter-web/2.7.0/spring-boot-starter-web-2.7.0.jar:/Users/xiaosa/.m2/repository/org/springframework/boot/spring-boot-starter/2.7.0/spring-boot-starter-2.7.0.jar:/Users/xiaosa/.m2/repository/org/springframework/boot/spring-boot/2.7.0/spring-boot-2.7.0.jar:/Users/xiaosa/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/2.7.0/spring-boot-autoconfigure-2.7.0.jar:/Users/xiaosa/.m2/repository/org/springframework/boot/spring-boot-starter-logging/2.7.0/spring-boot-starter-logging-2.7.0.jar:/Users/xiaosa/.m2/repository/ch/qos/logback/logback-classic/1.2.11/logback-classic-1.2.11.jar:/Users/xiaosa/.m2/repository/ch/qos/logback/logback-core/1.2.11/logback-core-1.2.11.jar:/Users/xiaosa/.m2/repository/org/slf4j/slf4j-api/1.7.36/slf4j-api-1.7.36.jar:/Users/xiaosa/.m2/repository/org/apache/logging/log4j/log4j-to-slf4j/2.17.2/log4j-to-slf4j-2.17.2.jar:/Users/xiaosa/.m2/repository/org/apache/logging/log4j/log4j-api/2.17.2/log4j-api-2.17.2.jar:/Users/xiaosa/.m2/repository/org/slf4j/jul-to-slf4j/1.7.36/jul-to-slf4j-1.7.36.jar:/Users/xiaosa/.m2/repository/jakarta/annotation/jakarta.annotation-api/1.3.5/jakarta.annotation-api-1.3.5.jar:/Users/xiaosa/.m2/repository/org/springframework/spring-core/5.3.20/spring-core-5.3.20.jar:/Users/xiaosa/.m2/repository/org/springframework/spring-jcl/5.3.20/spring-jcl-5.3.20.jar:/Users/xiaosa/.m2/repository/org/yaml/snakeyaml/1.30/snakeyaml-1.30.jar:/Users/xiaosa/.m2/repository/org/springframework/boot/spring-boot-starter-json/2.7.0/spring-boot-starter-json-2.7.0.jar:/Users/xiaosa/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.13.3/jackson-databind-2.13.3.jar:/Users/xiaosa/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.13.3/jackson-annotations-2.13.3.jar:/Users/xiaosa/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.13.3/jackson-core-2.13.3.jar:/Users/xiaosa/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jdk8/2.13.3/jackson-datatype-jdk8-2.13.3.jar:/Users/xiaosa/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jsr310/2.13.3/jackson-datatype-jsr310-2.13.3.jar:/Users/xiaosa/.m2/repository/com/fasterxml/jackson/module/jackson-module-parameter-names/2.13.3/jackson-module-parameter-names-2.13.3.jar:/Users/xiaosa/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/2.7.0/spring-boot-starter-tomcat-2.7.0.jar:/Users/xiaosa/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/9.0.63/tomcat-embed-core-9.0.63.jar:/Users/xiaosa/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/9.0.63/tomcat-embed-el-9.0.63.jar:/Users/xiaosa/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/9.0.63/tomcat-embed-websocket-9.0.63.jar:/Users/xiaosa/.m2/repository/org/springframework/spring-web/5.3.20/spring-web-5.3.20.jar:/Users/xiaosa/.m2/repository/org/springframework/spring-beans/5.3.20/spring-beans-5.3.20.jar:/Users/xiaosa/.m2/repository/org/springframework/spring-webmvc/5.3.20/spring-webmvc-5.3.20.jar:/Users/xiaosa/.m2/repository/org/springframework/spring-aop/5.3.20/spring-aop-5.3.20.jar:/Users/xiaosa/.m2/repository/org/springframework/spring-expression/5.3.20/spring-expression-5.3.20.jar:/Users/xiaosa/idea_project/starter-test/hello-starter/target/classes:/Users/xiaosa/.m2/repository/org/springframework/spring-context/5.3.20/spring-context-5.3.20.jar org.example.Main
----------CustomizedSpringApplicationRunListener.starting()
----------CustomizedSpringApplicationRunListener.environmentPrepared()

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.7.0)

----------CustomizedSpringApplicationRunListener.contextPrepared()
2023-03-25 01:32:12.774  INFO 15757 --- [           main] org.example.Main                         : Starting Main using Java 17.0.4.1 on XIAOSAdeMacBook-Pro.local with PID 15757 (/Users/xiaosa/idea_project/starter-test/web/target/classes started by xiaosa in /Users/xiaosa/idea_project/starter-test)
2023-03-25 01:32:12.776  INFO 15757 --- [           main] org.example.Main                         : No active profile set, falling back to 1 default profile: "default"
----------CustomizedSpringApplicationRunListener.contextLoaded()
2023-03-25 01:32:13.165  INFO 15757 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2023-03-25 01:32:13.170  INFO 15757 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-03-25 01:32:13.171  INFO 15757 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.63]
2023-03-25 01:32:13.210  INFO 15757 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-03-25 01:32:13.210  INFO 15757 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 411 ms
2023-03-25 01:32:13.360  INFO 15757 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2023-03-25 01:32:13.366  INFO 15757 --- [           main] org.example.Main                         : Started Main in 0.967 seconds (JVM running for 1.124)
----------CustomizedSpringApplicationRunListener.started()
----------CustomizedSpringApplicationRunListener.ready()

自定义运行监听器已生效。

原理

Springboot在启动时会加载一个SpringFactoriesLoader类，该类的作用就是加载classpath下所有的jar文件中的META-INF/spring.factories文件，并读取对应的配置。将相关的Listener注册到Spring容器中。容器在启动过程中，在不同的阶段调用相关的Listener。

已start为例：

SpringApplication.run()