springboot启动逻辑分析-------简述SpringApplication.run

Posted 2020-11-16 itivy

调用链路为：

    at org.springframework.boot.SpringApplication.run(SpringApplication.java:296)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
    at com.ivy.demo.DemoApplication.main(DemoApplication.java:16)

代码：

public ConfigurableApplicationContext run(String... args) {
        StopWatch stopWatch = new StopWatch();
　　　　 //(1).记录开始时间
        stopWatch.start();
        ConfigurableApplicationContext context = null;
        Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
        configureHeadlessProperty();
　　　　　//(2).获取配置的所有的SpringApplicationRunListener实现类，并封装到SpringApplicationRunListeners类
        SpringApplicationRunListeners listeners = getRunListeners(args);
　　　　　//(3).调用listener列表starting方法
        listeners.starting();
        try {
            ApplicationArguments applicationArguments = new DefaultApplicationArguments(
                    args);
　　　　　　　//(4).准备环境
            ConfigurableEnvironment environment = prepareEnvironment(listeners,
                    applicationArguments);
　　　　　　  //(5).根据spring.beaninfo.ignore配置是否忽略属性
            configureIgnoreBeanInfo(environment);
　　　　　　　//(6).打开欢迎字体
            Banner printedBanner = printBanner(environment);
　　　　　　　//(7).创建ApplicationContext
            context = createApplicationContext();
　　　　　　　//(8).获取错误报告类
            exceptionReporters = getSpringFactoriesInstances(
                    SpringBootExceptionReporter.class,
                    new Class[] { ConfigurableApplicationContext.class }, context);
            prepareContext(context, environment, listeners, applicationArguments,
                    printedBanner);
            refreshContext(context);
            afterRefresh(context, applicationArguments);
            stopWatch.stop();
            if (this.logStartupInfo) {
                new StartupInfoLogger(this.mainApplicationClass)
                        .logStarted(getApplicationLog(), stopWatch);
            }
            listeners.started(context);
            callRunners(context, applicationArguments);
        }
        catch (Throwable ex) {
            handleRunFailure(context, ex, exceptionReporters, listeners);
            throw new IllegalStateException(ex);
        }

        try {
            listeners.running(context);
        }
        catch (Throwable ex) {
            handleRunFailure(context, ex, exceptionReporters, null);
            throw new IllegalStateException(ex);
        }
        return context;
    }