httpservlet.java

JSWDK服务器

     * @param resp	an {@link HttpServletResponse} object that
     *			contains the response the servlet sends
     *			to the object
     * 
     * @exception IOException	if an input or output error is 
     *				detected when the servlet handles
     *				the request
     *
     * @exception ServletException	if the request for the POST
     *					could not be handled
     *
     *
     * @see javax.servlet.ServletOutputStream
     * @see javax.servlet.ServletResponse#setContentType
     *
     *
     */

    protected void doPost (HttpServletRequest req, HttpServletResponse resp)
	throws ServletException, IOException
    {
	String protocol = req.getProtocol();
	String msg = lStrings.getString("http.method_post_not_supported");
	if (protocol.endsWith("1.1")) {
	    resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
	} else {
	    resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
	}
    }




    /**
     * Receives an HTTP PUT request from the protected
     * <code>service</code> method and handles the
     * request. The PUT operation allows a client to 
     * place a file on the server and is similar to 
     * sending a file by FTP.
     *
     * <p>If you override this method, your method must leave intact
     * any content headers sent with the request (including
     * Content-Length, Content-Type, Content-Transfer-Encoding,
     * Content-Encoding, Content-Base, Content-Language, Content-Location,
     * Content-MD5, and Content-Range). If your method cannot
     * handle a content header, it must issue an error message
     * (HTTP 501 - Not Implemented) and discard the request.
     * For more information on HTTP 1.1, see RFC 2068
     * <a href="http://info.internet.isi.edu:80/in-notes/rfc/files/rfc2068.txt"></a>.
     *
     * <p>This method does not need to be either safe or idempotent.
     * Operations that <code>doPut</code> performs can have side
     * effects for which the user can be held accountable. If you
     * override this method, you may want to save a copy of the
     * affected URL in temporary storage.
     *
     * <p>If the HTTP PUT request is incorrectly formatted,
     * <code>doPut</code> returns an HTTP BAD_REQUEST message.
     *
     *
     * @param req	the {@link HttpServletRequest} object that
     *			contains the request the client made of
     *			the servlet
     *
     * @param resp	the {@link HttpServletResponse} object that
     *			contains the response the servlet returns
     *			to the client
     *
     * @exception IOException	if an input or output error occurs
     *				while the servlet is handling the
     *				PUT request
     *
     * @exception ServletException	if the request for the PUT
     *					cannot be handled
     *
     */
  
    protected void doPut (HttpServletRequest req, HttpServletResponse resp)
	throws ServletException, IOException
    {
	String protocol = req.getProtocol();
	String msg = lStrings.getString("http.method_put_not_supported");
	if (protocol.endsWith("1.1")) {
	    resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
	} else {
	    resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
	}
    }




    /**
     * 
     * Receives an HTTP DELETE request from the protected
     * <code>service</code> method and handles the
     * request. The DELETE
     * operation allows a client to remove a document
     * or Web page from the server.
     * 
     * <p>This method does not need to be either safe
     * or idempotent. Operations requested through
     * DELETE can have side effects for which users
     * can be held accountable. If you override this
     * method, you may want to save a copy of the affected
     * page in temporary storage.
     *
     * <p>If the HTTP DELETE request is incorrectly formatted,
     * <code>doDelete</code> returns an HTTP BAD_REQUEST
     * message.
     *
     *
     * @param req	the {@link HttpServletRequest} object that
     *			contains the request the client made of
     *			the servlet
     *
     *
     * @param resp	the {@link HttpServletResponse} object that
     *			contains the response the servlet returns
     *			to the client				
     *
     *
     * @exception IOException	if an input or output error occurs
     *				while the servlet is handling the
     *				DELETE request
     *
     * @exception ServletException	if the request for the
     *					DELETE cannot be handled
     *
     */
     
    protected void doDelete (HttpServletRequest req,
			     HttpServletResponse resp)
	throws ServletException, IOException
    {
	String protocol = req.getProtocol();
	String msg = lStrings.getString("http.method_delete_not_supported");
	if (protocol.endsWith("1.1")) {
	    resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
	} else {
	    resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
	}
    }
    




    private Method [] getAllDeclaredMethods (Class c) {
	if (c.getName().equals("javax.servlet.http.HttpServlet"))
	    return null;
	
	int j=0;
	Method [] parentMethods = getAllDeclaredMethods(c.getSuperclass());
	Method [] thisMethods = c.getDeclaredMethods();
	
	if (parentMethods!=null) {
	    Method [] allMethods =
		new Method [parentMethods.length + thisMethods.length];
	    for (int i=0; i<parentMethods.length; i++) {
		allMethods[i]=parentMethods[i];
		j=i;
	    }
	    j++;
	    for (int i=j; i<thisMethods.length+j; i++) {
		allMethods[i] = thisMethods[i-j];
	    }
	    return allMethods;
	}
	return thisMethods;
    }






    /**
     *
     * Receives an HTTP OPTIONS request from the protected
     * <code>service method and handles the request.
     * The OPTIONS request determines which HTTP methods 
     * the server supports and
     * returns an appropriate header. For example, if a servlet
     * overrides <code>doGet</code>, this method returns the
     * following header:
     *
     * <p><code>Allow: GET, HEAD, TRACE, OPTIONS</code>
     *
     * <p>You do not need to override this method unless your
     * servlet implements new HTTP methods, beyond those 
     * implemented by HTTP 1.1.
     *
     * @param req	the {@link HttpServletRequest} object that
     *			contains the request the client made of
     *			the servlet
     *
     *
     * @param resp	the {@link HttpServletResponse} object that
     *			contains the response the servlet returns
     *			to the client				
     *
     *
     * @exception IOException	if an input or output error occurs
     *				while the servlet is handling the
     *				OPTIONS request
     *
     * @exception ServletException	if the request for the
     *					OPTIONS cannot be handled
     *
     */
         
    protected void doOptions (HttpServletRequest req, HttpServletResponse resp)
	throws ServletException, IOException
    {
	Method [] methods = getAllDeclaredMethods(this.getClass());
	
	boolean ALLOW_GET = false;
	boolean ALLOW_HEAD = false;
	boolean ALLOW_POST = false;
	boolean ALLOW_PUT = false;
	boolean ALLOW_DELETE = false;
	boolean ALLOW_TRACE = true;
	boolean ALLOW_OPTIONS = true;
	
	for (int i=0; i<methods.length; i++) {
	    Method m = methods[i];
	    
	    if (m.getName().equals("doGet")) {
		ALLOW_GET = true;
		ALLOW_HEAD = true;
	    }
	    if (m.getName().equals("doPost")) 
		ALLOW_POST = true;
	    if (m.getName().equals("doPut"))
		ALLOW_PUT = true;
	    if (m.getName().equals("doDelete"))
		ALLOW_DELETE = true;
	    
	}
	
	String allow = null;
	if (ALLOW_GET)
	    if (allow==null) allow=METHOD_GET;
	if (ALLOW_HEAD)
	    if (allow==null) allow=METHOD_HEAD;
	    else allow += ", " + METHOD_HEAD;
	if (ALLOW_POST)
	    if (allow==null) allow=METHOD_POST;
	    else allow += ", " + METHOD_POST;
	if (ALLOW_PUT)
	    if (allow==null) allow=METHOD_PUT;
	    else allow += ", " + METHOD_PUT;
	if (ALLOW_DELETE)
	    if (allow==null) allow=METHOD_DELETE;
	    else allow += ", " + METHOD_DELETE;
	if (ALLOW_TRACE)
	    if (allow==null) allow=METHOD_TRACE;
	    else allow += ", " + METHOD_TRACE;
	if (ALLOW_OPTIONS)
	    if (allow==null) allow=METHOD_OPTIONS;
	    else allow += ", " + METHOD_OPTIONS;
	
	resp.setHeader("Allow", allow);
    }
    
    
    
    
    /**
     *
     * Receives an HTTP TRACE request from the protected
     * <code>service</code> method and handles the request.
     * HTTP TRACE returns the headers sent with the TRACE
     * request to the client, so that they can be used in
     * debugging. You do not usually need to override this method.
 
     *
     *
     *
     * @param req	the {@link HttpServletRequest} object that
     *			contains the request the client made of
     *			the servlet
     *
     *
     * @param resp	the {@link HttpServletResponse} object that
     *			contains the response the servlet returns
     *			to the client				
     *
     *
     * @exception IOException	if an input or output error occurs
     *				while the servlet is handling the
     *				TRACE request
     *
     * @exception ServletException	if the request for the
     *					TRACE cannot be handled
     *
     */

    protected void doTrace (HttpServletRequest req, HttpServletResponse resp) 
	throws ServletException, IOException
    {
	
	int responseLength;
	
	String CRLF = "\r\n";
	String responseString = "TRACE "+ req.getRequestURI()+
	    " " + req.getProtocol();
	
	Enumeration reqHeaderEnum = req.getHeaderNames();
	
	while( reqHeaderEnum.hasMoreElements() ) {
	    String headerName = (String)reqHeaderEnum.nextElement();
	    responseString += CRLF + headerName + ": " +
		req.getHeader(headerName); 
	}
	
	responseString += CRLF;
	
	responseLength = responseString.length();
	
	resp.setContentType("message/http");
	resp.setContentLength(responseLength);
	ServletOutputStream out = resp.getOutputStream();
	out.print(responseString);	
	out.close();
	return;
    }		





    /**
     *
     * Receives standard HTTP requests from the public
     * <code>service</code> method and dispatches
     * them to the <code>do</code><i>xxx</i> methods defined in 
     * this class. This method is an HTTP-specific version of the 
     * {@link javax.servlet.Servlet.service} method. You will probably