关于java:SpringBoot-创建容器

spring 容器的创立对应 SpringApplication 中 run 中调用的 createApplicationContext 办法。这里创立了一个 web 容器，接下就进去 prepareContext 容器筹备阶段：

    private void prepareContext(ConfigurableApplicationContext context, ConfigurableEnvironment environment,            SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments, Banner printedBanner) {        //为容器设置环境        context.setEnvironment(environment);        //这里的空实现留给开发者扩大，设置数据转换的ConversionService        postProcessApplicationContext(context);        //执行容器中的 Initializers 的 initialize 办法        applyInitializers(context);        listeners.contextPrepared(context);        if (this.logStartupInfo) {            logStartupInfo(context.getParent() == null);            logStartupProfileInfo(context);        }        // Add boot specific singleton beans        ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();        beanFactory.registerSingleton("springApplicationArguments", applicationArguments);        if (printedBanner != null) {            beanFactory.registerSingleton("springBootBanner", printedBanner);        }        if (beanFactory instanceof DefaultListableBeanFactory) {            ((DefaultListableBeanFactory) beanFactory)                    .setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);        }        if (this.lazyInitialization) {            context.addBeanFactoryPostProcessor(new LazyInitializationBeanFactoryPostProcessor());        }        // Load the sources        Set<Object> sources = getAllSources();        Assert.notEmpty(sources, "Sources must not be empty");        load(context, sources.toArray(new Object[0]));        listeners.contextLoaded(context);    }

看一下这里的 load 办法,这里次要把咱们的启动类作为 Bean 注册到了 Spring 的容器中。

    protected void load(ApplicationContext context, Object[] sources) {        if (logger.isDebugEnabled()) {            logger.debug("Loading source " + StringUtils.arrayToCommaDelimitedString(sources));        }        BeanDefinitionLoader loader = createBeanDefinitionLoader(getBeanDefinitionRegistry(context), sources);        if (this.beanNameGenerator != null) {            loader.setBeanNameGenerator(this.beanNameGenerator);        }        if (this.resourceLoader != null) {            loader.setResourceLoader(this.resourceLoader);        }        if (this.environment != null) {            loader.setEnvironment(this.environment);        }        loader.load();    }

    /**     * Load the sources into the reader.     * @return the number of loaded beans     */    int load() {        int count = 0;        for (Object source : this.sources) {            count += load(source);        }        return count;    }    private int load(Object source) {        Assert.notNull(source, "Source must not be null");        if (source instanceof Class<?>) {            return load((Class<?>) source);        }        if (source instanceof Resource) {            return load((Resource) source);        }        if (source instanceof Package) {            return load((Package) source);        }        if (source instanceof CharSequence) {            return load((CharSequence) source);        }        throw new IllegalArgumentException("Invalid source type " + source.getClass());    }    private int load(Class<?> source) {        if (isGroovyPresent() && GroovyBeanDefinitionSource.class.isAssignableFrom(source)) {            // Any GroovyLoaders added in beans{} DSL can contribute beans here            GroovyBeanDefinitionSource loader = BeanUtils.instantiateClass(source, GroovyBeanDefinitionSource.class);            load(loader);        }        if (isEligible(source)) {            this.annotatedReader.register(source);            return 1;        }        return 0;    }

再来看下 contextLoaded 办法，这里将上下文设置到监听器中，同时也把监听器增加到上下文中。最初公布了一个 ApplicationPreparedEvent 事件。

    public void contextLoaded(ConfigurableApplicationContext context) {        for (ApplicationListener<?> listener : this.application.getListeners()) {            if (listener instanceof ApplicationContextAware) {                ((ApplicationContextAware) listener).setApplicationContext(context);            }            context.addApplicationListener(listener);        }        this.initialMulticaster.multicastEvent(new ApplicationPreparedEvent(this.application, this.args, context));    }