Spring Boot 几乎所有的工作都是在 SpringApplication 的run方法中完成的，下面给出了run 方法的源码，重点是通过run 方法来了解Spring Boot 的整体工作流程，后续章节会详细分析各个步骤的工作原理和源码。
/**
* Run the Spring application, creating and refreshing a new
* {@link ApplicationContext}.
* @param args the application arguments (usually passed from a Java main method)
* @return a running {@link ApplicationContext}
*/
public ConfigurableApplicationContext run(String... args) {
// 1、
StopWatch stopWatch = new StopWatch();
stopWatch.start();
ConfigurableApplicationContext context = null;
FailureAnalyzers analyzers = null;
// 2、
configureHeadlessProperty();
// 3、
SpringApplicationRunListeners listeners = getRunListeners(args);
listeners.starting();
try {
// 4、
ApplicationArguments applicationArguments = new DefaultApplicationArguments(
args);
ConfigurableEnvironment environment = prepareEnvironment(listeners,
applicationArguments);
// 5、
Banner printedBanner = printBanner(environment);
// 6、
context = createApplicationContext();
// 7、
analyzers = new FailureAnalyzers(context);
// 8、
prepareContext(context, environment, listeners, applicationArguments,
printedBanner);
// 9、
refreshContext(context);
// 10、
afterRefresh(context, applicationArguments);
// 11、
listeners.finished(context, null);
// 12、
stopWatch.stop();
// 13、
if (this.logStartupInfo) {
new StartupInfoLogger(this.mainApplicationClass)
.logStarted(getApplicationLog(), stopWatch);
}
return context;
}
catch (Throwable ex) {
// 14、
handleRunFailure(context, listeners, analyzers, ex);
throw new IllegalStateException(ex);
}
}
源码:
run |- 1 stopWatch.start()
|- 2 configureHeadlessProperty
|- 3 listeners.starting()
|- 4 prepareEnvironment
|- 5 printBanner(environment)
|- 6 createApplicationContext()
|- 7 new FailureAnalyzers(context)
|- 8 prepareContext(...)
|- 9 refreshContext(context)
|- 10 afterRefresh
|- 11 listeners.finished
|- 12 stopWatch.stop()
|- 13 new StartupInfoLogger(...).logStarted(...)
|- 14 handleRunFailure(...)
