Spring容器刷新—01—prepareRefresh

深藏阁楼爱情的钟 2023-09-25 17:12 3阅读 0赞

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这次的内容是上图中的第1步，容器刷新前的准备工作。基本上都是一些初始化动作。

### 关键源码 ###

下面是这部分的涉及到的源码中的关键部分：

public abstract class AbstractApplicationContext extends DefaultResourceLoader
            implements ConfigurableApplicationContext {
    
        private long startupDate;
    
        /** Flag that indicates whether this context is currently active. */
        private final AtomicBoolean active = new AtomicBoolean();
    
        /** Flag that indicates whether this context has been closed already. */
        private final AtomicBoolean closed = new AtomicBoolean();
    
        /** Environment used by this context. */
        @Nullable
        private ConfigurableEnvironment environment;
    
        protected void prepareRefresh() {
            // Switch to active.
            this.startupDate = System.currentTimeMillis();
    
            // 1. 初始化状态位
            this.closed.set(false);
            this.active.set(true);
    
            if (logger.isDebugEnabled()) {
                if (logger.isTraceEnabled()) {
                    logger.trace("Refreshing " + this);
                } else {
                    logger.debug("Refreshing " + getDisplayName());
                }
            }
    
            // 2. 留给子类的扩展方法
            // Initialize any placeholder property sources in the context environment.
            initPropertySources();
    
            // 3. 验证必须的配置项是否存在
            // Validate that all properties marked as required are resolvable:
            // see ConfigurablePropertyResolver#setRequiredProperties
            getEnvironment().validateRequiredProperties();
    
            // 4. 处理早期事件
            // Store pre-refresh ApplicationListeners...
            if (this.earlyApplicationListeners == null) {
                this.earlyApplicationListeners = new LinkedHashSet<>(this.applicationListeners);
            } else {
                // Reset local application listeners to pre-refresh state.
                this.applicationListeners.clear();
                this.applicationListeners.addAll(this.earlyApplicationListeners);
            }
    
            // Allow for the collection of early ApplicationEvents,
            // to be published once the multicaster is available...
            this.earlyApplicationEvents = new LinkedHashSet<>()

[format_png]: https://img-blog.csdnimg.cn/img_convert/03850df0cf79df3abd0d625c5aa6b78f.webp?x-oss-process=image/format,png
[format_png 1]: https://img-blog.csdnimg.cn/img_convert/81ed9eb89e1000b1b6d4832c610acca3.webp?x-oss-process=image/format,png