BeanDefinition的Resource定位——3

 1 protected final void refreshBeanFactory() throws BeansException {
 2         // 这里判断，如果已经建立了BeanFactory，则销毁并关闭该BeanFactory
 3         if (hasBeanFactory()) {
 4             destroyBeans();
 5             closeBeanFactory();
 6         }
 7         // 这里是创建并设置持有的DefaultListableBeanFactory的地方
 8         // 同时调用loadBeanDefinitions载入BeanDefinition的信息
 9         try {
10             DefaultListableBeanFactory beanFactory = createBeanFactory();
11             beanFactory.setSerializationId(getId());
12             customizeBeanFactory(beanFactory);
13             loadBeanDefinitions(beanFactory);
14             synchronized (this.beanFactoryMonitor) {
15                 this.beanFactory = beanFactory;
16             }
17         }
18         catch (IOException ex) {
19             throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
20         }
21     }

1 // 这就是在上下文中创建DefaultListableBeanFactory的地方，而getInternalParentBeanFacoty()
2     // 的具体实现可以
3     // 查看AbstractApplicationContext中的实现，会根据容器已有的双亲IoC容器的信息来生成
4     // DefaultListableBeanFactory的双亲IoC容器
5     protected DefaultListableBeanFactory createBeanFactory() {
6         return new DefaultListableBeanFactory(getInternalParentBeanFactory());
7     }

1 // 这里是使用BeanDefinitionReader载入Bean定义的地方，因为允许有多种载入方式，虽然用得
2     // 最多的事XML定义的形式，这里通过一个抽象函数把具体的实现委托给子类来完成
3     protected abstract void loadBeanDefinitions(DefaultListableBeanFactory beanFactory)
4             throws BeansException, IOException;

 1 // 对于取得Resource的具体过程，我们可以看看DefaultResourceLoader是怎样完成的
 2     public Resource getResource(String location) {
 3         Assert.notNull(location, "Location must not be null");
 4         // 
 5         if (location.startsWith("/")) {
 6             return getResourceByPath(location);
 7         }
 8         else if (location.startsWith(CLASSPATH_URL_PREFIX)) {
 9             return new ClassPathResource(location.substring(CLASSPATH_URL_PREFIX.length()), getClassLoader());
10         }
11         else {
12             try {
13                 // Try to parse the location as a URL...
14                 URL url = new URL(location);
15                 return new UrlResource(url);
16             }
17             catch (MalformedURLException ex) {
18                 // No URL -> resolve as resource path.
19                 return getResourceByPath(location);
20             }
21         }
22     }

1 protected Resource getResourceByPath(String path) {
2         if (path != null && path.startsWith("/")) {
3             path = path.substring(1);
4         }
5         return new FileSystemResource(path);
6     }