protected Class determineContextClass(ServletContext servletContext) throws ApplicationContextException ...{   
<span style="color:red;">   
    //获得需要实例化的CONTEXT类名,在web.xml中有设置,如果没有设置,那么为空   
    String contextClassName = servletContext.getInitParameter(CONTEXT_CLASS_PARAM);   
    if (contextClassName != null) ...{   
      try ...{   
        return ClassUtils.forName(contextClassName);   
      }   
      catch (ClassNotFoundException ex) ...{   
        throw new ApplicationContextException(   
            "Failed to load custom context class [" + contextClassName + "]", ex);   
      }   
    }   
    //如果在spring web.xml中没有设置context类位置,那么取得默认context   
    else ...{   
      //取得defaultStrategies配置文件中的WebApplicationContext属性   
      contextClassName = defaultStrategies.getProperty(WebApplicationContext.class.getName());   
      try ...{   
        return ClassUtils.forName(contextClassName);   
      }   
      catch (ClassNotFoundException ex) ...{   
        throw new ApplicationContextException(   
            "Failed to load default context class [" + contextClassName + "]", ex);   
      }   
    }   
</span>   
  }  

private static final Properties defaultStrategies;   
  
  static ...{   
    // Load default strategy implementations from properties file.   
    // This is currently strictly internal and not meant to be customized   
    // by application developers.   
    try ...{   
<span style="color:red;">   
      //设置classpath为contextLoader同级目录   
      ClassPathResource resource = new ClassPathResource(DEFAULT_STRATEGIES_PATH, ContextLoader.class);   
      //加载该目录下的所有properties文件   
      defaultStrategies = PropertiesLoaderUtils.loadProperties(resource);   
</span>   
    }   
    catch (IOException ex) ...{   
      throw new IllegalStateException("Could not load 'ContextLoader.properties': " + ex.getMessage());   
    }   
  }