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spring boot 命令行启动 spring boot 命令行启动的方式

posuoren 人气:5

在使用spring boot 构建应用启动时,我们在工作中都是通过命令行来启动应用,有时候会需要一些特定的参数以在应用启动时,做一些初始化的操作。

spring boot 提供了 CommandLineRunner 和 ApplicationRunner 这两个接口供用户使用。

1. CommandLineRunner

1.1 声明:

@FunctionalInterface
public interface CommandLineRunner {

  /**
   * Callback used to run the bean.
   * @param args incoming main method arguments
   * @throws Exception on error
   */
  void run(String... args) throws Exception;

}

1.2 使用:

package com.example.consoleapplication;

import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

@Component
public class TestRunner implements CommandLineRunner {

  @Override
  public void run(String... args) {
    // Do something...
    for(String arg: args){
      System.out.println(arg);
    }
    System.out.print("test command runner");
  }
}

1.3 运行结果

运行: java -jar build/libs/consoleapplication-0.0.1-SNAPSHOT.jar -sdfsaf sdfas,

结果如下:

2019-03-16 17:31:56.544  INFO 18679 --- [           main] c.e.consoleapplication.DemoApplication   : No active profile set, falling back to default profiles: default
2019-03-16 17:31:57.195  INFO 18679 --- [           main] c.e.consoleapplication.DemoApplication   : Started DemoApplication in 16.172 seconds (JVM running for 16.65)
-sdfsaf
sdfas
test command runner%

2. ApplicationRunner

2.1 声明

/**
 * Interface used to indicate that a bean should <em>run</em> when it is contained within
 * a {@link SpringApplication}. Multiple {@link ApplicationRunner} beans can be defined
 * within the same application context and can be ordered using the {@link Ordered}
 * interface or {@link Order @Order} annotation.
 *
 * @author Phillip Webb
 * @since 1.3.0
 * @see CommandLineRunner
 */
@FunctionalInterface
public interface ApplicationRunner {

  /**
   * Callback used to run the bean.
   * @param args incoming application arguments
   * @throws Exception on error
   */
  void run(ApplicationArguments args) throws Exception;

}

2.2 使用

ApplicationRunner 和 CommandLineRunner 的使用是有差别的:

package com.example.consoleapplication;

import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
import org.springframework.boot.ApplicationArguments;

@Component
public class TestApplicationRunner implements ApplicationRunner {

  @Override
  public void run(ApplicationArguments args) throws Exception {
    // Do something...
    System.out.println("option arg names" + args.getOptionNames());
    System.out.println("non option+" + args.getNonOptionArgs());
  }
}

2.3 运行结果

运行命令 java -jar build/libs/consoleapplication-0.0.1-SNAPSHOT.jar -non1 non2 --option=1, 结果为:

2019-03-16 18:08:08.528  INFO 19778 --- [           main] c.e.consoleapplication.DemoApplication   : No active profile set, falling back to default profiles: default
2019-03-16 18:08:09.166  INFO 19778 --- [           main] c.e.consoleapplication.DemoApplication   : Started DemoApplication in 16.059 seconds (JVM running for 16.56)
test
option arg names[option]
non option+[-non1, non2]-non1
non2
--option=1
test%

可以看到, optional 参数名有 option, non optional 参数有 -non1 和 non2

3. 小结

CommandLineRunner 和 ApplicationRunner 都能实现命令行应用启动时根据参数获取我们需要的值,做特殊的逻辑。但两者有所不同,推荐使用 ApplicationRunner 的 optional 参数, 方便扩展。

4. 参考文档

https://docs.spring.io/spring-boot/docs/2.0.5.RELEASE/reference/htmlsingle/

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