计时器与启动加载器

计时器

import org.junit.jupiter.api.Test;
import org.springframework.util.StopWatch;

public class StopWatchDemo {
    @Test
    public void test() throws InterruptedException {
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("task1");
        Thread.sleep(2000L);
        stopWatch.stop();
        stopWatch.start("task2");
        Thread.sleep(3000L);
        stopWatch.stop();
        stopWatch.start("task3");
        Thread.sleep(1000L);
        stopWatch.stop();
        System.out.println(stopWatch.prettyPrint());
    }
}

StopWatch '': running time = 6008888191 ns
---------------------------------------------
ns         %     Task name
---------------------------------------------
2004276665  033%  task1
3003999368  050%  task2
1000612158  017%  task3

启动加载器

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

/**
 * 启动加载器
 * @see SpringApplication#callRunners(org.springframework.context.ApplicationContext, org.springframework.boot.ApplicationArguments)
 * {@link CommandLineRunner}
 */
@Component
@Order
public class FirstCommandLineRunner implements CommandLineRunner {

    @Override
    public void run(String... args) throws Exception {
        System.out.println("\u001B[32m First CommandLineRunner");
    }
}

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

/**
 * 启动加载器
 * {@link ApplicationRunner}
 */
@Order
@Component
public class FirstApplicationRunner implements ApplicationRunner{
    @Override
    public void run(ApplicationArguments args) throws Exception {
        System.out.println("\u001B[32m First ApplicationRunner");
    }
}

源码

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

getBeansOfType

	@Override
	public <T> Map<String, T> getBeansOfType(@Nullable Class<T> type, boolean includeNonSingletons, boolean allowEagerInit)
			throws BeansException {

		assertBeanFactoryActive();
		return getBeanFactory().getBeansOfType(type, includeNonSingletons, allowEagerInit);
	}

assertBeanFactoryActive

	protected void assertBeanFactoryActive() {
		if (!this.active.get()) {  //是在refreshContext->org.springframework.context.support.AbstractApplicationContext#prepareRefresh赋值的
			if (this.closed.get()) {
				throw new IllegalStateException(getDisplayName() + " has been closed already");
			}
			else {
				throw new IllegalStateException(getDisplayName() + " has not been refreshed yet");
			}
		}
	}

org.springframework.context.support.AbstractApplicationContex#prepareRefresh

protected void prepareRefresh() {
		// Switch to active.
		this.startupDate = System.currentTimeMillis();
		this.closed.set(false);
		this.active.set(true);

ApplicationRunner对比CommandLineRunner

• callRunner

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

ApplicationArguments初始化

	ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);

//最后执行的是org.springframework.core.env.SimpleCommandLineArgsParser#parse
public CommandLineArgs parse(String... args) {
		CommandLineArgs commandLineArgs = new CommandLineArgs();
		for (String arg : args) {
			if (arg.startsWith("--")) {
				String optionText = arg.substring(2);
				String optionName;
				String optionValue = null;
				int indexOfEqualsSign = optionText.indexOf('=');
				if (indexOfEqualsSign > -1) {
					optionName = optionText.substring(0, indexOfEqualsSign);
					optionValue = optionText.substring(indexOfEqualsSign + 1);
				}
				else {
					optionName = optionText;
				}
				if (optionName.isEmpty()) {
					throw new IllegalArgumentException("Invalid argument syntax: " + arg);
				}
				commandLineArgs.addOptionArg(optionName, optionValue);
			}
			else {
				commandLineArgs.addNonOptionArg(arg);
			}
		}
		return commandLineArgs;
	}