BeanDefinition的Resource定位——2

  1 public class FileSystemXmlApplicationContext extends AbstractXmlApplicationContext {
  2 
  3     /**
  4      * Create a new FileSystemXmlApplicationContext for bean-style configuration.
  5      * @see #setConfigLocation
  6      * @see #setConfigLocations
  7      * @see #afterPropertiesSet()
  8      */
  9     public FileSystemXmlApplicationContext() {
 10     }
 11 
 12     /**
 13      * Create a new FileSystemXmlApplicationContext for bean-style configuration.
 14      * @param parent the parent context
 15      * @see #setConfigLocation
 16      * @see #setConfigLocations
 17      * @see #afterPropertiesSet()
 18      */
 19     public FileSystemXmlApplicationContext(ApplicationContext parent) {
 20         super(parent);
 21     }
 22 
 23     /**
 24      * 这个构造函数的configLocation包含的是BeanDefinition所在的文件路径
 25      * Create a new FileSystemXmlApplicationContext, loading the definitions
 26      * from the given XML file and automatically refreshing the context.
 27      * @param configLocation file path
 28      * @throws BeansException if context creation failed
 29      */
 30     public FileSystemXmlApplicationContext(String configLocation) throws BeansException {
 31         this(new String[] {configLocation}, true, null);
 32     }
 33 
 34     /**
 35      * 这个构造函数允许configLocation包含多个BeanDefinition的文件路径
 36      * Create a new FileSystemXmlApplicationContext, loading the definitions
 37      * from the given XML files and automatically refreshing the context.
 38      * @param configLocations array of file paths
 39      * @throws BeansException if context creation failed
 40      */
 41     public FileSystemXmlApplicationContext(String... configLocations) throws BeansException {
 42         this(configLocations, true, null);
 43     }
 44 
 45     /**
 46      * 这个构造函数在允许configLocation包含多个BeanDefinition的文件路径的同时，还允许指定
 47      * 自己的双亲IoC容器
 48      * Create a new FileSystemXmlApplicationContext with the given parent,
 49      * loading the definitions from the given XML files and automatically
 50      * refreshing the context.
 51      * @param configLocations array of file paths
 52      * @param parent the parent context
 53      * @throws BeansException if context creation failed
 54      */
 55     public FileSystemXmlApplicationContext(String[] configLocations, ApplicationContext parent) throws BeansException {
 56         this(configLocations, true, parent);
 57     }
 58 
 59     /**
 60      * Create a new FileSystemXmlApplicationContext, loading the definitions
 61      * from the given XML files.
 62      * @param configLocations array of file paths
 63      * @param refresh whether to automatically refresh the context,
 64      * loading all bean definitions and creating all singletons.
 65      * Alternatively, call refresh manually after further configuring the context.
 66      * @throws BeansException if context creation failed
 67      * @see #refresh()
 68      */
 69     public FileSystemXmlApplicationContext(String[] configLocations, boolean refresh) throws BeansException {
 70         this(configLocations, refresh, null);
 71     }
 72 
 73     /**
 74      * 在对象的初始化过程中，调用refresh函数载入BeanDefinition，这个refresh启动了
 75      * BeanDefinition的载入过程，我们会在下面进行详细分析
 76      * Create a new FileSystemXmlApplicationContext with the given parent,
 77      * loading the definitions from the given XML files.
 78      * @param configLocations array of file paths
 79      * @param refresh whether to automatically refresh the context,
 80      * loading all bean definitions and creating all singletons.
 81      * Alternatively, call refresh manually after further configuring the context.
 82      * @param parent the parent context
 83      * @throws BeansException if context creation failed
 84      * @see #refresh()
 85      */
 86     public FileSystemXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent)
 87             throws BeansException {
 88 
 89         super(parent);
 90         setConfigLocations(configLocations);
 91         if (refresh) {
 92             refresh();
 93         }
 94     }
 95 
 96 
 97     /**
 98      * 这是应用于文件系统中Resource的实现，通过构造一个FileSystemResource来得到一个在文件
 99      * 系统中定位的BeanDefinition
100      * 这个getResourceByPath是在BeanDefinitionReader的loadBeanDefinition中被调用的
101      * loadBeanDfinition采用了模板模式，具体的定位实现实际上是由各个子类来完成的
102      *
103      *
104      * Resolve resource paths as file system paths.
105      * <p>Note: Even if a given path starts with a slash, it will get
106      * interpreted as relative to the current VM working directory.
107      * This is consistent with the semantics in a Servlet container.
108      * @param path path to the resource
109      * @return Resource handle
110      * @see org.springframework.web.context.support.XmlWebApplicationContext#getResourceByPath
111      */
112     @Override
113     protected Resource getResourceByPath(String path) {
114         if (path != null && path.startsWith("/")) {
115             path = path.substring(1);
116         }
117         return new FileSystemResource(path);
118     }
119 
120 }