SpringApplication.run 開啓 一

1、解析SpringFraworkWork第一步如何加載相關的jar包的 ？

@SuppressWarnings({ "unchecked", "rawtypes" })
	private void initialize(Object[] sources) {
		if (sources != null && sources.length > 0) {
			this.sources.addAll(Arrays.asList(sources));
		}
        
        /*用來判斷是否爲web環境*/
		this.webEnvironment = deduceWebEnvironment();
        /*加載相關的引用對象*/
		setInitializers((Collection) getSpringFactoriesInstances(
				ApplicationContextInitializer.class));
		setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
		this.mainApplicationClass = deduceMainApplicationClass();
	}

 ---spring 是如何判斷是否爲web環境的呢？

 

private static final String[] WEB_ENVIRONMENT_CLASSES = { "javax.servlet.Servlet",
			"org.springframework.web.context.ConfigurableWebApplicationContext" };
/*其實就是查找上面的類是否被引入了*/
private boolean deduceWebEnvironment() {
		for (String className : WEB_ENVIRONMENT_CLASSES) {
			if (!ClassUtils.isPresent(className, null)) {
				return false;
			}
		}
		return true;
	}

後面就是加載相關的jar進行初始化，加載監聽，這些加載完成後啓動了run方法

public ConfigurableApplicationContext run(String... args) {
		StopWatch stopWatch = new StopWatch();
		stopWatch.start();
		ConfigurableApplicationContext context = null;
		FailureAnalyzers analyzers = null;
		configureHeadlessProperty();
		SpringApplicationRunListeners listeners = getRunListeners(args);
		listeners.starting();
		try {
			ApplicationArguments applicationArguments = new DefaultApplicationArguments(
					args);
			ConfigurableEnvironment environment = prepareEnvironment(listeners,
					applicationArguments);
			Banner printedBanner = printBanner(environment);
			context = createApplicationContext();
			analyzers = new FailureAnalyzers(context);
			prepareContext(context, environment, listeners, applicationArguments,
					printedBanner);
			refreshContext(context);
			afterRefresh(context, applicationArguments);
			listeners.finished(context, null);
			stopWatch.stop();
			if (this.logStartupInfo) {
				new StartupInfoLogger(this.mainApplicationClass)
						.logStarted(getApplicationLog(), stopWatch);
			}
			return context;
		}
		catch (Throwable ex) {
			handleRunFailure(context, listeners, analyzers, ex);
			throw new IllegalStateException(ex);
		}
	}

監聽類

private SpringApplicationRunListeners getRunListeners(String[] args) {
		Class<?>[] types = new Class<?>[] { SpringApplication.class, String[].class };
		return new SpringApplicationRunListeners(logger, getSpringFactoriesInstances(
				SpringApplicationRunListener.class, types, this, args));
	}

在運行的監測類中加入了日誌，監聽的類

SpringApplicationRunListeners(Log log,
			Collection<? extends SpringApplicationRunListener> listeners) {
		this.log = log;
		this.listeners = new ArrayList<SpringApplicationRunListener>(listeners);
	}

爲什麼會在加載這個監視器嗎？

英文我們在pom文件中首先應用springboot。在進行初始化的時候，去加載這個jar包總

 這裏有個加載資源文件的

 

	    /**
	 * The location to look for factories.
	 * <p>Can be present in multiple JAR files.
	 */
	public static final String FACTORIES_RESOURCE_LOCATION = "META-INF/spring.factories";
public static List<String> loadFactoryNames(Class<?> factoryClass, ClassLoader classLoader) {
		String factoryClassName = factoryClass.getName();
		try {
			Enumeration<URL> urls = (classLoader != null ? classLoader.getResources(FACTORIES_RESOURCE_LOCATION) :
					ClassLoader.getSystemResources(FACTORIES_RESOURCE_LOCATION));
			List<String> result = new ArrayList<String>();
			while (urls.hasMoreElements()) {
				URL url = urls.nextElement();
				Properties properties = PropertiesLoaderUtils.loadProperties(new UrlResource(url));
				String factoryClassNames = properties.getProperty(factoryClassName);
				result.addAll(Arrays.asList(StringUtils.commaDelimitedListToStringArray(factoryClassNames)));
			}
			return result;
		}
		catch (IOException ex) {
			throw new IllegalArgumentException("Unable to load [" + factoryClass.getName() +
					"] factories from location [" + FACTORIES_RESOURCE_LOCATION + "]", ex);
		}
	}

這個會在當前的線程下查找META-INF文件，由於我加載了springboot jar 包

獲取name 後進行實例化。

至此加載其他的資源，就啓動了一個