SpringBoot项目启动时执行初始化操作

SpringBooot中的CommandLineRunner接口会在所有Spring Beans初始化之后，SpringApplication.run()之前执行。

1.添加pom引用

<?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>com.itstudy</groupId>
    <artifactId>demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <name>demo</name>
    <url>http://www.example.com</url>
    <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>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>1.5.9.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

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

2.添加两个CommandLineRunner

import org.springframework.boot.CommandLineRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Component
@Order(2) //指定顺序
public class Runner1 implements CommandLineRunner {
    @Override
    public void run(String... args) throws Exception {
        System.out.println("Runner1 ===========");
    }
}

import org.springframework.boot.CommandLineRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Component
@Order(1) //指定顺序
public class Runner2 implements CommandLineRunner {
    @Override
    public void run(String... args) throws Exception {
        System.out.println("Runner2 ===========");
    }
}

3.启动项目

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

@SpringBootApplication
public class App {

    public static void main(String[] args) {

        System.out.println("启动中...");

        SpringApplication.run(App.class, args);

        System.out.println("启动成功");
    }
}

4.运行结果

启动中...

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.9.RELEASE)

2019-06-11 09:49:12.152  INFO 4536 --- [           main] com.itstudy.App                          : Starting App on liuwma with PID 4536 (D:\javawork\ideawork\runnerdemo\target\classes started by Administrator in D:\javawork\ideawork)
2019-06-11 09:49:12.156  INFO 4536 --- [           main] com.itstudy.App                          : No active profile set, falling back to default profiles: default
2019-06-11 09:49:12.247  INFO 4536 --- [           main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@5123a213: startup date [Tue Jun 11 09:49:12 CST 2019]; root of context hierarchy
2019-06-11 09:49:13.277  INFO 4536 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
Runner2 ===========
Runner1 ===========
2019-06-11 09:49:13.300  INFO 4536 --- [           main] com.itstudy.App                          : Started App in 1.604 seconds (JVM running for 2.483)
启动成功