springboot项目启动成功后执行一段代码的两种方式

springboot项目启动成功后执行一段代码的两种方式| Id | Title | DateAdded | SourceUrl | PostType | Body | BlogId | Description | DateUpdated | IsMarkdown | EntryName | CreatedTime | IsActive | AutoDesc | AccessPermission |

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| 14939677| springboot项目启动成功后执行一段代码的两种方式| 2021-06-27T01:23:00| | BlogPost|

实现ApplicationRunner接口

package com.lnjecit.lifecycle;
import org.springframework.boot.ApplicationArguments;

import org.springframework.boot.ApplicationRunner;

import org.springframework.core.annotation.Order;

import org.springframework.stereotype.Component;
/**

@author lnj
createTime 2018-11-07 22:37

**/

@Component

public class ApplicationRunnerImpl implements ApplicationRunner {

@Override

public void run(ApplicationArguments args) throws Exception {

System.out.println("通过实现ApplicationRunner接口，在spring boot项目启动后打印参数");

String[] sourceArgs = args.getSourceArgs();

for (String arg : sourceArgs) {

System.out.print(arg + " ");

}

System.out.println();

}

}

 

项目启动后，会打印如下信息：

 

 

实现CommandLineRunner接口

package com.lnjecit.lifecycle;
import org.springframework.boot.CommandLineRunner;

import org.springframework.stereotype.Component;
/**

@author lnj
createTime 2018-11-07 22:25

**/

@Component

public class CommandLineRunnerImpl implements CommandLineRunner {

@Override

public void run(String... args) throws Exception {

System.out.println("通过实现CommandLineRunner接口，在spring boot项目启动后打印参数");

for (String arg : args) {

System.out.print(arg + " ");

}

System.out.println();

}

}

 

 

 两种实现方式的不同之处在于run方法中接收的参数类型不一样

 

指定执行顺序

当项目中同时实现了ApplicationRunner和CommondLineRunner接口时，可使用Order注解或实现Ordered接口来指定执行顺序，值越小越先执行

 

原理

通过调试可以发现都是在 org.springframework.boot.SpringApplication#run(java.lang.String...)方法内的afterRefresh（上下文刷新后处理）方法时，会执行callRunners方法。

afterRefresh方法具体实现如下： 

protected void afterRefresh(ConfigurableApplicationContext context,
        ApplicationArguments args) {
    callRunners(context, args);
}

callRunners方法具体实现如下： 

private void callRunners(ApplicationContext context, ApplicationArguments args) {
    List<Object> runners = new ArrayList<Object>();
    runners.addAll(context.getBeansOfType(ApplicationRunner.class).values());
    runners.addAll(context.getBeansOfType(CommandLineRunner.class).values());
    AnnotationAwareOrderComparator.sort(runners);
    for (Object runner : new LinkedHashSet<Object>(runners)) {
        if (runner instanceof ApplicationRunner) {
            callRunner((ApplicationRunner) runner, args);
        }
        if (runner instanceof CommandLineRunner) {
            callRunner((CommandLineRunner) runner, args);
        }
    }
}

 可以看出上下文完成刷新后，依次调用注册的runners, runners的类型为 ApplicationRunner 或 CommandLineRunner

 

案例地址

https://github.com/linj6/springboot-learn/tree/master/springboot-runner

 

参考资料

https://blog.csdn.net/zknxx/article/details/52196427

| 648658| | 2024-04-29T21:16:00| false| | 2021-06-27T01:23:20.467| true| 实现ApplicationRunner接口 package com.lnjecit.lifecycle; import org.springframework.boot.ApplicationArguments; import org.springframework.boot.Application| Anonymous|