Spring WebUtils source code parsing

Spring WebUtils source code parsing

 

2. spring Source Code
WebUtils
At org. springframework. web. the WebUtils In the util package is a very useful tool class. It provides easy-to-use proxy methods for many Servlet APIs, reducing the complexity of accessing Servlet APIs, it can be seen as a door class of common Servlet API methods.
The following methods facilitate access to objects and attributes in HttpServletRequest and HttpSession:

 

(1) getSessionAttribute

Obtain the object of the specific attribute name of HttpSession. Otherwise, you must use request. getSession. getAttribute (name) to perform the same operation;

 

Java code

1. /*** Check the given request for a session attribute of the given name. * Returns null if there is no session or if the session has no such attribute. * Does not create a new session if none has existed before! * @ Param request current HTTP request * @ param name the name of the session attribute * @ return the value of the session attribute, ornullIf not found */public static Object getSessionAttribute (HttpServletRequest request, String name) {Assert. notNull (request, Request must not be null); HttpSession session = request. getSession (false); return (session! = Null? Session. getAttribute (name): null );}

   (2) getRequiredSessionAttribute

   Similar to the previous method, it only requires that the HttpSession has the specified attribute. Otherwise, an exception is thrown;

    

   Java code
   1. /*** Check the given request for a session attribute of the given name. * Throws an exception if there is no session or if the session has no such * attribute. does not create a new session if none has existed before! * @ Param request current HTTP request * @ param name the name of the session attribute * @ return the value of the session attribute, ornullIf not found * @ throws IllegalStateException if the session attribute cocould not be found */public static Object getRequiredSessionAttribute (HttpServletRequest request, String name) throws IllegalStateException {Object attr = getSessionAttribute (request, request, name); if (attr = null) {throw new IllegalStateException (No session attribute '+ name + 'found);} return attr ;}

      (3) setSessionAttribute

      Specifies the attribute setting value for the session. If the input value is null, this attribute is removed from the session.

       

      Java code
      1. /*** Set the session attribute with the given name to the given value. * Removes the session attribute if value is null, if a session existed at all. * Does not create a new session if not necessary! * @ Param request current HTTP request * @ param name the name of the session attribute * @ param value the value of the session attribute */public static void setSessionAttribute (HttpServletRequest request, String name, object value) {Assert. notNull (request, Request must not be null); if (value! = Null) {request. getSession (). setAttribute (name, value);} else {HttpSession session = request. getSession (false); if (session! = Null) {session. removeAttribute (name );}}}

         (4) exposeRequestAttributes

         Add the Map element to the attribute list of ServletRequest. when the request is forwarded to the next handler, these request attributes can be accessed;

          

         Java code
         1. /*** Expose the given Map as request attributes, using the keys as attribute names * and the values as corresponding attribute values. keys need to be Strings. * @ param request current HTTP request * @ param attributes the attributes Map */public static void exposeRequestAttributes (ServletRequest request, Map Attributes) {Assert. notNull (request, Request must not be null); Assert. notNull (attributes, Attributes Map must not be null); for (Map. Entry Entry: attributes. entrySet () {request. setAttribute (entry. getKey (), entry. getValue ());}}

            (5) getCookie

            Obtain the Cookie object of a specific name in HttpServletRequest. If you need to create a Cookie, Spring also provides a convenient CookieGenerator tool class;

             

            Java code
            1. /*** Retrieve the first cookie with the given name. note that multiple * cookies can have the same name but different paths or domains. * @ param request current servlet request * @ param name cookie name * @ return the first cookie with the given name, ornullIf none is found */public static Cookie getCookie (HttpServletRequest request, String name) {Assert. notNull (request, Request must not be null); Cookie cookies [] = request. getCookies (); if (cookies! = Null) {for (Cookie cookie: cookies) {if (name. equals (cookie. getName () {return cookie ;}} return null ;}

               (6) extractFilenameFromUrlPath

               Extract the file name from the Url

                

               Java code
               1. /*** Extract the URL filename from the given request URL path. * Correctly resolves nested paths such as/products/view.html as well. * @ param urlPath the request URL path (e.g. /index.html) * @ return the extracted URI filename (e.g. index) */public static String extractFilenameFromUrlPath (String urlPath) {String filename = extractFullFilenameFromUrlPath (urlPath); int dotIndex = filename. lastInd ExOf ('.'); if (dotIndex! =-1) {filename = filename. substring (0, dotIndex);} return filename;}/*** Extract the full URL filename (including file extension) from the given request URL path. * Correctly resolves nested paths such as/products/view.html as well. * @ param urlPath the request URL path (e.g. /products/index.html) * @ return the extracted URI filename (e.g. index.html) */public static String extractFullFilen AmeFromUrlPath (String urlPath) {int end = urlPath. indexOf (';'); if (end =-1) {end = urlPath. indexOf ('? '); If (end =-1) {end = urlPath. length () ;}} int begin = urlPath. lastIndexOf ('/', end) + 1; return urlPath. substring (begin, end );}