摘要：本文介绍了如何通过CommanLineRunner和ApplicationRunner来实现系统启动任务。

CommanLineRunner

我们来创建自定义的MyCommanLineRunner类，并实现CommanLineRunner接口即可。

package com.example.commandlinerunner;

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

import java.util.Arrays;

/**
 * @author: WJZheng
 * @date: 2020/3/17 11:19
 * @description:
 */

@Component
@Order(99) //如果有多个CommanLineRunner，则需要指定优先级，数字越小优先级越高
public class MyCommandLineRunner1 implements CommandLineRunner {
    @Override
    public void run(String... args) throws Exception {
        //run方法里面的args参数就是SpringBoot主类中main方法传递的args
        System.out.println(this.toString() + Arrays.toString(args));
    }
}

package com.example.commandlinerunner;

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

import java.util.Arrays;

/**
 * @author: WJZheng
 * @date: 2020/3/17 11:19
 * @description:
 */

@Component
@Order(100)
public class MyCommandLineRunner2 implements CommandLineRunner {
    @Override
    public void run(String... args) throws Exception {
        System.out.println(this.toString() + Arrays.toString(args));
    }
}

我们在Terminal中运行命令

1	mvn package

将项目打包成jar包，然后运行

1	java -jar commandlinerunner-0.0.1-SNAPSHOT.jar ThreeBody BallLightning ChineseSun

通过命令行的方式传递args参数，在控制台我们可以看到以下信息，即系统启动的时候会自动运行两个CommanLineRunner类的run方法。

ApplicatinoRunner

我们再通过ApplicationRunner来实现系统启动，与上面一样创建自定义类，并实现ApplicationRunner接口即可。我们同样也可以通过@Order来设置其优先级。

package com.example.commandlinerunner;

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

import java.util.Arrays;
import java.util.List;
import java.util.Set;

/**
 * @author: WJZheng
 * @date: 2020/3/17 11:37
 * @description:
 */
@Component
@Order(99)
public class MyApplicationRunner1 implements ApplicationRunner {
    @Override
    public void run(ApplicationArguments args) throws Exception {
        //获取启动的所有参数
        String[] sourceArgs = args.getSourceArgs();
        System.out.println("sourceArgs: " + Arrays.toString(sourceArgs));
        List<String> noOptionArgs = args.getNonOptionArgs();
        System.out.println("nonOptionArgs: " + noOptionArgs);
        Set<String> optionNames = args.getOptionNames();
        System.out.println("--------------------------");
        for (String name : optionNames) {
            System.out.println(name + ": " + args.getOptionValues(name));
        }
        System.out.println("End: " + this.toString());
    }
}

package com.example.commandlinerunner;

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

import java.util.Arrays;
import java.util.List;
import java.util.Set;

/**
 * @author: WJZheng
 * @date: 2020/3/17 11:37
 * @description:
 */
@Component
@Order(100)
public class MyApplicationRunner2 implements ApplicationRunner {
    @Override
    public void run(ApplicationArguments args) throws Exception {
        //获取启动的所有参数
        String[] sourceArgs = args.getSourceArgs();
        System.out.println("sourceArgs: " + Arrays.toString(sourceArgs));
        //ApplicationRunner可以获取两种不同的参数，一种是noOptionArgs，一种是OptionArgs
        List<String> noOptionArgs = args.getNonOptionArgs();
        System.out.println("nonOptionArgs: " + noOptionArgs);
        Set<String> optionNames = args.getOptionNames();
        System.out.println("--------------------------");
        for (String name : optionNames) {
            System.out.println(name + ": " + args.getOptionValues(name));
        }
        System.out.println("End: " + this.toString());
    }
}