SpringBoot中CommandLineRunner和ApplicationRunner接口解析和使用

@Component
public class LearnCommandLineRunner implements CommandLineRunner {

	@Override
	public void run(String... args) {
		System.out.println("LearnCommandLineRunner running");
	}
}

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;

}

public interface ApplicationRunner {

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

}

@Order(value = 1)
@Component
public class LearnCommandLineRunner implements CommandLineRunner {

	@Override
	public void run(String... args) {
		System.out.println("LearnCommandLineRunner running");
	}
}

public ConfigurableApplicationContext run(String... args) {
		// 创建 StopWatch 对象，用于统计 run 方法启动时长。
		StopWatch stopWatch = new StopWatch();
		// 启动统计。
		stopWatch.start();
		ConfigurableApplicationContext context = null;
		Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
		// 配置 headless 属性。
		configureHeadlessProperty();
		// 获得 SpringApplicationRunListener 数组，
		// 该数组封装于 SpringApplicationRunListeners 对象的 listeners 中。
		SpringApplicationRunListeners listeners = getRunListeners(args);
		// 启动监听，遍历 SpringApplicationRunListener 数组每个元素，并执行。
		listeners.starting();
		try {
			//创建 ApplicationArguments 对象
			ApplicationArguments applicationArguments = new DefaultApplicationArguments(
					args);
			// 加载属性配置，包括所有的配置属性（如：application.properties 中和外部的属性配置）
			ConfigurableEnvironment environment = prepareEnvironment(listeners,
					applicationArguments);
			configureIgnoreBeanInfo(environment);
			// 打印 Banner
			Banner printedBanner = printBanner(environment);
			// 创建容器
			context = createApplicationContext();

			// 异常报告器
			exceptionReporters = getSpringFactoriesInstances(
					SpringBootExceptionReporter.class,
					new Class[] { ConfigurableApplicationContext.class }, context);
			// 准备容器，组件对象之间进行关联
			prepareContext(context, environment, listeners, applicationArguments,
					printedBanner);
			// 初始化容器
			refreshContext(context);
			// 初始化操作之后执行，默认实现为空。
			afterRefresh(context, applicationArguments);
			// 停止时长统计
			stopWatch.stop();
			// 打印启动日志
			if (this.logStartupInfo) {
				new StartupInfoLogger(this.mainApplicationClass)
						.logStarted(getApplicationLog(), stopWatch);
			}
			// 通知监听器：容器启动完成。
			listeners.started(context);
			// 调用 ApplicationRunner 和 CommandLineRunner 的运行方法。
			callRunners(context, applicationArguments);
		}
		catch (Throwable ex) {
			// 异常处理
			handleRunFailure(context, ex, exceptionReporters, listeners);
			throw new IllegalStateException(ex);
		}

		try {
			// 通知监听器：容器正在运行。
			listeners.running(context);
		}
		catch (Throwable ex) {
			// 异常处理
			handleRunFailure(context, ex, exceptionReporters, null);
			throw new IllegalStateException(ex);
		}
		return context;
	}

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

	private void callRunner(ApplicationRunner runner, ApplicationArguments args) {
		try {
			(runner).run(args);
		}
		catch (Exception ex) {
			throw new IllegalStateException("Failed to execute ApplicationRunner", ex);
		}
	}

	private void callRunner(CommandLineRunner runner, ApplicationArguments args) {
		try {
			(runner).run(args.getSourceArgs());
		}
		catch (Exception ex) {
			throw new IllegalStateException("Failed to execute CommandLineRunner", ex);
		}
	}