MVCServlet


1   /**
2    *
3    * Magnolia and its source-code is licensed under the LGPL.
4    * You may copy, adapt, and redistribute this file for commercial or non-commercial use.
5    * When copying, adapting, or redistributing this document in keeping with the guidelines above,
6    * you are required to provide proper attribution to obinary.
7    * If you reproduce or distribute the document without making any substantive modifications to its content,
8    * please use the following attribution line:
9    *
10   * Copyright 1993-2005 obinary Ltd. (http://www.obinary.com) All rights reserved.
11   *
12   */
13  package info.magnolia.cms.servlets;
14  
15  import java.io.IOException  ;
16  
17  import javax.servlet.ServletException  ;
18  import javax.servlet.http.HttpServlet  ;
19  import javax.servlet.http.HttpServletRequest  ;
20  import javax.servlet.http.HttpServletResponse  ;
21  
22  import org.apache.log4j.Logger;
23  
24  
25  /**
26   * The servlet gets a MVCHandler with the method getHandler. The method getCommand of this returned handler is called to
27   * map the request parameters to a command. Then execute() is called which uses reflection to call a method. Each method
28   * returns a string defining the view. After that, renderHtml is called.
29   * <p>
30   * Make a subclass to provide you own handler(s).
31   * @author Philipp Bracher
32   * @version $Id: AdminInterfaceServlet.java 661 2005-05-03 14:10:45Z philipp $
33   */
34  public abstract class MVCServlet extends HttpServlet   {
35  
36      /**
37       * Stable serialVersionUID.
38       */
39      private static final long serialVersionUID = 222L;
40  
41      private static Logger log = Logger.getLogger(MVCServlet.class);
42  
43      /**
44       * @see HttpServlet#doPost(HttpServletRequest,HttpServletResponse)
45       */
46      protected void doPost(HttpServletRequest   request, HttpServletResponse   response) throws ServletException  ,
47          IOException   {
48          doGet(request, response);
49      }
50  
51      /**
52       * @see HttpServlet#doGet(HttpServletRequest, HttpServletResponse)
53       */
54      protected void doGet(HttpServletRequest   request, HttpServletResponse   response) throws ServletException  , IOException   {
55  
56          // http://issues.apache.org/bugzilla/show_bug.cgi?id=22666
57          //
58          // 1. The Coyote HTTP/1.1 connector has a useBodyEncodingForURI attribute which
59          // if set to true will use the request body encoding to decode the URI query
60          // parameters.
61          // - The default value is true for TC4 (breaks spec but gives consistent
62          // behaviour across TC4 versions)
63          // - The default value is false for TC5 (spec compliant but there may be
64          // migration issues for some apps)
65          // 2. The Coyote HTTP/1.1 connector has a URIEncoding attribute which defaults to
66          // ISO-8859-1.
67          // 3. The parameters class (o.a.t.u.http.Parameters) has a QueryStringEncoding
68          // field which defaults to the URIEncoding. It must be set before the parameters
69          // are parsed to have an effect.
70          //
71          // Things to note regarding the servlet API:
72          // 1. HttpServletRequest.setCharacterEncoding() normally only applies to the
73          // request body NOT the URI.
74          // 2. HttpServletRequest.getPathInfo() is decoded by the web container.
75          // 3. HttpServletRequest.getRequestURI() is not decoded by container.
76          //
77          // Other tips:
78          // 1. Use POST with forms to return parameters as the parameters are then part of
79          // the request body.
80  
81          // this can throw an exception in jetty
82          try {
83              request.setCharacterEncoding("UTF-8"); //$NON-NLS-1$
84          }
85          catch (java.lang.IllegalStateException   e) {
86              log.error("can't set character encoding for the request", e); //$NON-NLS-1$
87          }
88  
89          // why do i have to change it if request was setted? But i have to!
90          response.setCharacterEncoding("UTF-8"); //$NON-NLS-1$
91  
92          response.setContentType("text/html; charset=UTF-8"); //$NON-NLS-1$
93  
94          MVCServletHandler handler = getHandler(request, response);
95  
96          if (handler == null) {
97              log.error("no handler found"); //$NON-NLS-1$
98              return;
99          }
100 
101         if (log.isDebugEnabled()) {
102             log.debug("handler: " + handler.getName()); //$NON-NLS-1$
103         }
104         String   command = handler.getCommand();
105         if (log.isDebugEnabled()) {
106             log.debug("calling command: " + command); //$NON-NLS-1$
107         }
108         String   view = handler.execute(command);
109         if (log.isDebugEnabled()) {
110             log.debug("calling view: " + view); //$NON-NLS-1$
111         }
112 
113         handler.renderHtml(view);
114 
115     }
116 
117     /**
118      * @param request
119      * @return
120      */
121     protected abstract MVCServletHandler getHandler(HttpServletRequest   request, HttpServletResponse   response);
122 }
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags