Java ServletContext.getRequestDispatcher方法代码示例

import javax.servlet.ServletContext; //导入方法依赖的package包/类
/**
 * This method handles the HTTP request for the user token resolution. It
 * calls the <code>resolveUsertoken</code> method. After the token has been
 * resolved, it forwards the request to the target path configured in the
 * <code>TOKENHANDLER_FORWARD</code> property.
 * 
 * @param request
 *            the HTTP servlet request with the user token to be resolved
 * @param response
 *            the HTTP servlet response for the request
 * @param servletContext
 *            the servlet context of the request
 * @throws ServletException
 *             if the forwarding of the request or the call to the platform
 *             fails
 * @throws IOException
 *             if the forwarding of the request fails
 */
static public void processHTTPRequest(HttpServletRequest request,
        HttpServletResponse response, ServletContext servletContext)
        throws ServletException, IOException {

    String usertoken = request.getParameter(Constants.USERTOKEN);
    String instanceId = request.getParameter(Constants.INSTANCE_ID);
    String bssId = request.getParameter(Constants.CM_ID);
    String subKey = request.getParameter(Constants.SUB_KEY);

    String userId = BssClient.resolveUsertoken(request.getSession(),
            usertoken, instanceId, subKey, bssId);

    if (userId == null || userId.length() == 0) {
        logger.error("Error: missing userId!");
        response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
        return;
    }

    String forward = wsProxyInfo.getForward();
    logger.debug("Forward to " + forward);
    RequestDispatcher rd = servletContext.getRequestDispatcher(forward);
    rd.forward(request, response);
}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
/**
 * Method associated to a tile and called immediately before the tile 
 * is included.  This implementation calls an <code>Action</code>. 
 * No servlet is set by this method.
 *
 * @param tileContext Current tile context.
 * @param request Current request.
 * @param response Current response.
 * @param servletContext Current servlet context.
 */
public void perform(
	ComponentContext tileContext,
	HttpServletRequest request,
	HttpServletResponse response,
	ServletContext servletContext)
	throws ServletException, IOException {

	RequestDispatcher rd = servletContext.getRequestDispatcher(url);
	if (rd == null) {
		throw new ServletException(
			"Controller can't find url '" + url + "'.");
	}

	rd.include(request, response);
}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
/**
 * @see org.apache.struts.tiles.Controller#execute(org.apache.struts.tiles.ComponentContext, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, javax.servlet.ServletContext)
 */
public void execute(
	ComponentContext tileContext,
	HttpServletRequest request,
	HttpServletResponse response,
	ServletContext servletContext)
	throws Exception {
           
	RequestDispatcher rd = servletContext.getRequestDispatcher(url);
	if (rd == null) {
		throw new ServletException(
			"Controller can't find url '" + url + "'.");
	}

	rd.include(request, response);

}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
/**
 * Handle an HTTP status code or Java exception by forwarding control
 * to the location included in the specified errorPage object.  It is
 * assumed that the caller has already recorded any request attributes
 * that are to be forwarded to this page.  Return <code>true</code> if
 * we successfully utilized the specified error page location, or
 * <code>false</code> if the default error report should be rendered.
 *
 * @param request The request being processed
 * @param response The response being generated
 * @param errorPage The errorPage directive we are obeying
 */
protected boolean custom(Request request, Response response,
                         ErrorPage errorPage) {

    if (container.getLogger().isDebugEnabled())
        container.getLogger().debug("Processing " + errorPage);

    request.setPathInfo(errorPage.getLocation());

    try {

        // Reset the response (keeping the real error code and message)
        response.resetBuffer(true);

        // Forward control to the specified location
        ServletContext servletContext =
            request.getContext().getServletContext();
        RequestDispatcher rd =
            servletContext.getRequestDispatcher(errorPage.getLocation());
        rd.forward(request.getRequest(), response.getResponse());

        // If we forward, the response is suspended again
        response.setSuspended(false);

        // Indicate that we have successfully processed this custom page
        return (true);

    } catch (Throwable t) {

        // Report our failure to process this custom page
        container.getLogger().error("Exception Processing " + errorPage, t);
        return (false);

    }

}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
/**
 * Handle an HTTP status code or Java exception by forwarding control
 * to the location included in the specified errorPage object.  It is
 * assumed that the caller has already recorded any request attributes
 * that are to be forwarded to this page.  Return <code>true</code> if
 * we successfully utilized the specified error page location, or
 * <code>false</code> if the default error report should be rendered.
 *
 * @param request The request being processed
 * @param response The response being generated
 * @param errorPage The errorPage directive we are obeying
 */
protected boolean custom(Request request, Response response,
                         ErrorPage errorPage) {

    if (debug >= 1)
        log("Processing " + errorPage);

    // Validate our current environment
    if (!(request instanceof HttpRequest)) {
        if (debug >= 1)
            log(" Not processing an HTTP request --> default handling");
        return (false);     // NOTE - Nothing we can do generically
    }
    HttpServletRequest hreq =
        (HttpServletRequest) request.getRequest();
    if (!(response instanceof HttpResponse)) {
        if (debug >= 1)
            log("Not processing an HTTP response --> default handling");
        return (false);     // NOTE - Nothing we can do generically
    }
    HttpServletResponse hres =
        (HttpServletResponse) response.getResponse();

    try {

        // Reset the response if possible (else IllegalStateException)
        hres.reset();

        // Forward control to the specified location
        ServletContext servletContext =
            request.getContext().getServletContext();
        RequestDispatcher rd =
            servletContext.getRequestDispatcher(errorPage.getLocation());
        rd.forward(hreq, hres);

        // If we forward, the response is suspended again
        response.setSuspended(false);

        // Indicate that we have successfully processed this custom page
        return (true);

    } catch (Throwable t) {

        // Report our failure to process this custom page
        log("Exception Processing " + errorPage, t);
        return (false);

    }

}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
public String getFileText( String originalPath, boolean virtual ) throws IOException {
try {
    ServletContextAndPath csAndP = getServletContextAndPath( originalPath, virtual );
    ServletContext context = csAndP.getServletContext();
    String path = csAndP.getPath();

    RequestDispatcher rd =
	context.getRequestDispatcher( path );
    if ( rd == null ) {
	throw new IOException("Couldn't get request dispatcher for path: " + path );
    }
    ByteArrayServletOutputStream basos = new ByteArrayServletOutputStream();
    ResponseIncludeWrapper responseIncludeWrapper =
	new ResponseIncludeWrapper(res, basos );
    rd.include(req, responseIncludeWrapper );

    //We can't assume the included servlet flushed its output
    responseIncludeWrapper.flushOutputStreamOrWriter();
    byte[] bytes = basos.toByteArray();

    //Assume that the default encoding is what was used to encode the bytes. Questionable.
    String retVal = new String( bytes );

    //make an assumption that an empty response is a failure.  This is a problem if a truly empty file 
    //were included, but not sure how else to tell.
    if ( retVal.equals("") ) {
	throw new IOException("Couldn't find file: " + path );
    }
    return retVal;
} catch (ServletException e) {
    throw new IOException("Couldn't include file: " + originalPath + " because of ServletException: " + e.getMessage() );
}
   }
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
private void buildSurveyHtml() throws Exception{
		HttpServletRequest request=Struts2Utils.getRequest();
		HttpServletResponse response=Struts2Utils.getResponse();
		String url = "";
		String name = "";
		ServletContext sc = ServletActionContext.getServletContext();

		String file_name = request.getParameter("file_name");
		url = "/design/my-collect.action?surveyId=402880ea4675ac62014675ac7b3a0000";
		// 这是生成的html文件名,如index.htm.
		name = "/survey.htm";
		name = sc.getRealPath(name);
		
		RequestDispatcher rd = sc.getRequestDispatcher(url);
		final ByteArrayOutputStream os = new ByteArrayOutputStream();

		final ServletOutputStream stream = new ServletOutputStream() {
			public void write(byte[] data, int offset, int length) {
				os.write(data, offset, length);
			}

			public void write(int b) throws IOException {
				os.write(b);
			}
		};
		
		final PrintWriter pw = new PrintWriter(new OutputStreamWriter(os,"utf-8"));

		HttpServletResponse rep = new HttpServletResponseWrapper(response) {
			public ServletOutputStream getOutputStream() {
				return stream;
			}

			public PrintWriter getWriter() {
				return pw;
			}
		};

//		rd.include(request, rep);
		rd.forward(request,rep);
		pw.flush();
		
		// 把jsp输出的内容写到xxx.htm
		File file = new File(name);
		if (!file.exists()) {
			file.createNewFile();
		}
		FileOutputStream fos = new FileOutputStream(file);
		
		os.writeTo(fos);
		fos.close();
	}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
public void jspWriteToHtml(String url, String filePath,String fileName) throws Exception {
	HttpServletRequest request = Struts2Utils.getRequest();
	HttpServletResponse response = Struts2Utils.getResponse();
	ServletContext sc = ServletActionContext.getServletContext();
	url = "/my-survey-design!previewDev.action?surveyId=402880ea4675ac62014675ac7b3a0000";
	// 这是生成的html文件名,如index.htm
	filePath = filePath.replace("/", File.separator);
	filePath = filePath.replace("\\", File.separator);
	String fileRealPath = sc.getRealPath("/") + filePath;
	RequestDispatcher rd = sc.getRequestDispatcher(url);
	final ByteArrayOutputStream os = new ByteArrayOutputStream();

	final ServletOutputStream stream = new ServletOutputStream() {
		public void write(byte[] data, int offset, int length) {
			os.write(data, offset, length);
		}

		public void write(int b) throws IOException {
			os.write(b);
		}
	};

	final PrintWriter pw = new PrintWriter(new OutputStreamWriter(os,
			"UTF-8"));

	HttpServletResponse rep = new HttpServletResponseWrapper(response) {
		public ServletOutputStream getOutputStream() {
			return stream;
		}

		public PrintWriter getWriter() {
			return pw;
		}
	};

	rd.forward(request, response);
	pw.flush();

	File file2 = new File(fileRealPath);
	if (!file2.exists() || !file2.isDirectory()) {
		file2.mkdirs();
	}
	File file = new File(fileRealPath + fileName);
	if (!file.exists()) {
		file.createNewFile();
	}
	FileOutputStream fos = new FileOutputStream(file);
	os.writeTo(fos);
	fos.close();
}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
@Override
public String getFileText(String originalPath, boolean virtual) throws IOException {
	try {
		ServletContextAndPath csAndP = getServletContextAndPath(originalPath, virtual);
		ServletContext context = csAndP.getServletContext();
		String path = csAndP.getPath();
		RequestDispatcher rd = context.getRequestDispatcher(path);
		if (rd == null) {
			throw new IOException("Couldn't get request dispatcher for path: " + path);
		}
		ByteArrayServletOutputStream basos = new ByteArrayServletOutputStream();
		ResponseIncludeWrapper responseIncludeWrapper = new ResponseIncludeWrapper(context, req, res, basos);
		rd.include(req, responseIncludeWrapper);
		// We can't assume the included servlet flushed its output
		responseIncludeWrapper.flushOutputStreamOrWriter();
		byte[] bytes = basos.toByteArray();

		// Assume platform default encoding unless otherwise specified
		String retVal;
		if (inputEncoding == null) {
			retVal = new String(bytes);
		} else {
			retVal = new String(bytes, B2CConverter.getCharset(inputEncoding));
		}

		// make an assumption that an empty response is a failure. This is
		// a problem
		// if a truly empty file
		// were included, but not sure how else to tell.
		if (retVal.equals("") && !req.getMethod().equalsIgnoreCase(org.apache.coyote.http11.Constants.HEAD)) {
			throw new IOException("Couldn't find file: " + path);
		}
		return retVal;
	} catch (ServletException e) {
		throw new IOException(
				"Couldn't include file: " + originalPath + " because of ServletException: " + e.getMessage());
	}
}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
@Override
public String getFileText(String originalPath, boolean virtual)
        throws IOException {
    try {
        ServletContextAndPath csAndP = getServletContextAndPath(
                originalPath, virtual);
        ServletContext context = csAndP.getServletContext();
        String path = csAndP.getPath();
        RequestDispatcher rd = context.getRequestDispatcher(path);
        if (rd == null) {
            throw new IOException(
                    "Couldn't get request dispatcher for path: " + path);
        }
        ByteArrayServletOutputStream basos =
            new ByteArrayServletOutputStream();
        ResponseIncludeWrapper responseIncludeWrapper =
            new ResponseIncludeWrapper(context, req, res, basos);
        rd.include(req, responseIncludeWrapper);
        //We can't assume the included servlet flushed its output
        responseIncludeWrapper.flushOutputStreamOrWriter();
        byte[] bytes = basos.toByteArray();

        //Assume platform default encoding unless otherwise specified
        String retVal;
        if (inputEncoding == null) {
            retVal = new String( bytes );
        } else {
            retVal = new String (bytes,
                    B2CConverter.getCharset(inputEncoding));
        }

        //make an assumption that an empty response is a failure. This is
        // a problem
        // if a truly empty file
        //were included, but not sure how else to tell.
        if (retVal.equals("") && !req.getMethod().equalsIgnoreCase(
                org.apache.coyote.http11.Constants.HEAD)) {
            throw new IOException("Couldn't find file: " + path);
        }
        return retVal;
    } catch (ServletException e) {
        throw new IOException("Couldn't include file: " + originalPath
                + " because of ServletException: " + e.getMessage());
    }
}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
/**
 * Handle an HTTP status code or Java exception by forwarding control
 * to the location included in the specified errorPage object.  It is
 * assumed that the caller has already recorded any request attributes
 * that are to be forwarded to this page.  Return <code>true</code> if
 * we successfully utilized the specified error page location, or
 * <code>false</code> if the default error report should be rendered.
 *
 * @param request The request being processed
 * @param response The response being generated
 * @param errorPage The errorPage directive we are obeying
 */
private boolean custom(Request request, Response response,
                         ErrorPage errorPage) {

    if (container.getLogger().isDebugEnabled())
        container.getLogger().debug("Processing " + errorPage);

    try {
        // Forward control to the specified location
        ServletContext servletContext =
            request.getContext().getServletContext();
        RequestDispatcher rd =
            servletContext.getRequestDispatcher(errorPage.getLocation());

        if (rd == null) {
            container.getLogger().error(
                sm.getString("standardHostValue.customStatusFailed", errorPage.getLocation()));
            return false;
        }

        if (response.isCommitted()) {
            // Response is committed - including the error page is the
            // best we can do 
            rd.include(request.getRequest(), response.getResponse());
        } else {
            // Reset the response (keeping the real error code and message)
            response.resetBuffer(true);
            response.setContentLength(-1);

            rd.forward(request.getRequest(), response.getResponse());

            // If we forward, the response is suspended again
            response.setSuspended(false);
        }

        // Indicate that we have successfully processed this custom page
        return (true);

    } catch (Throwable t) {
        ExceptionUtils.handleThrowable(t);
        // Report our failure to process this custom page
        container.getLogger().error("Exception Processing " + errorPage, t);
        return (false);

    }
}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
@Override
public void dispatch(ServletContext context, String path) {
    synchronized (asyncContextLock) {
        if (log.isDebugEnabled()) {
            logDebug("dispatch   ");
        }
        check();
        if (dispatch != null) {
            throw new IllegalStateException(
                    sm.getString("asyncContextImpl.dispatchingStarted"));
        }
        if (request.getAttribute(ASYNC_REQUEST_URI)==null) {
            request.setAttribute(ASYNC_REQUEST_URI, request.getRequestURI());
            request.setAttribute(ASYNC_CONTEXT_PATH, request.getContextPath());
            request.setAttribute(ASYNC_SERVLET_PATH, request.getServletPath());
            request.setAttribute(ASYNC_PATH_INFO, request.getPathInfo());
            request.setAttribute(ASYNC_QUERY_STRING, request.getQueryString());
        }
        final RequestDispatcher requestDispatcher = context.getRequestDispatcher(path);
        if (!(requestDispatcher instanceof AsyncDispatcher)) {
            throw new UnsupportedOperationException(
                    sm.getString("asyncContextImpl.noAsyncDispatcher"));
        }
        final AsyncDispatcher applicationDispatcher =
                (AsyncDispatcher) requestDispatcher;
        final ServletRequest servletRequest = getRequest();
        final ServletResponse servletResponse = getResponse();
        Runnable run = new Runnable() {
            @Override
            public void run() {
                request.getCoyoteRequest().action(ActionCode.ASYNC_DISPATCHED, null);
                try {
                    applicationDispatcher.dispatch(servletRequest, servletResponse);
                }catch (Exception x) {
                    //log.error("Async.dispatch",x);
                    throw new RuntimeException(x);
                }
            }
        };

        this.dispatch = run;
        this.request.getCoyoteRequest().action(ActionCode.ASYNC_DISPATCH, null);
        clearServletRequestResponse();
    }
}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
public String getFileText(String originalPath, boolean virtual)
        throws IOException {
    try {
        ServletContextAndPath csAndP = getServletContextAndPath(
                originalPath, virtual);
        ServletContext context = csAndP.getServletContext();
        String path = csAndP.getPath();
        RequestDispatcher rd = context.getRequestDispatcher(path);
        if (rd == null) {
            throw new IOException(
                    "Couldn't get request dispatcher for path: " + path);
        }
        ByteArrayServletOutputStream basos =
            new ByteArrayServletOutputStream();
        ResponseIncludeWrapper responseIncludeWrapper =
            new ResponseIncludeWrapper(context, req, res, basos);
        rd.include(req, responseIncludeWrapper);
        //We can't assume the included servlet flushed its output
        responseIncludeWrapper.flushOutputStreamOrWriter();
        byte[] bytes = basos.toByteArray();

        //Assume platform default encoding unless otherwise specified
        String retVal;
        if (inputEncoding == null) {
            retVal = new String( bytes );
        } else {
            retVal = new String (bytes, inputEncoding);
        }

        //make an assumption that an empty response is a failure. This is
        // a problem
        // if a truly empty file
        //were included, but not sure how else to tell.
        if (retVal.equals("") && !req.getMethod().equalsIgnoreCase(
                org.apache.coyote.http11.Constants.HEAD)) {
            throw new IOException("Couldn't find file: " + path);
        }
        return retVal;
    } catch (ServletException e) {
        throw new IOException("Couldn't include file: " + originalPath
                + " because of ServletException: " + e.getMessage());
    }
}
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
private void doInterpret(String requestURL,Map<String, Object> variables, OutputStream output) throws IOException, ServletException {
 	/**
      * 创建ServletContext对象，用于获取RequestDispatcher对象
      */
     ServletContext sc = request.getSession().getServletContext();
     /**
      * 根据传过来的相对文件路径，生成一个reqeustDispatcher的包装类
      */
     RequestDispatcher rd = sc.getRequestDispatcher(requestURL);
     /**
      * 创建一个ByteArrayOutputStream的字节数组输出流,用来存放输出的信息
      */
     final ByteArrayOutputStream baos = new ByteArrayOutputStream();
      
     /**
      * ServletOutputStream是抽象类，必须实现write的方法
      */
     final ServletOutputStream outputStream = new ServletOutputStream(){
         
         public void write(int b) throws IOException {
             /**
              * 将指定的字节写入此字节输出流
              */
             baos.write(b);
         }

	@SuppressWarnings("unused")
public boolean isReady() {
		return false;
	}

     }; 
     /**
      * 通过现有的 OutputStream 创建新的 PrintWriter
      * OutputStreamWriter 是字符流通向字节流的桥梁：可使用指定的 charset 将要写入流中的字符编码成字节
      */
     final PrintWriter pw = new PrintWriter(new OutputStreamWriter(baos, config.getOutputEncoding() ),true);
     /**
      * 生成HttpServletResponse的适配器，用来包装response
      */
     HttpServletResponse resp = new HttpServletResponseWrapper(response){
         /**
          * 调用getOutputStream的方法(此方法是ServletResponse中已有的)返回ServletOutputStream的对象
          * 用来在response中返回一个二进制输出对象
          * 此方法目的是把源文件写入byteArrayOutputStream
          */
         public ServletOutputStream getOutputStream(){
             return outputStream;
         }
          
         /**
          * 再调用getWriter的方法(此方法是ServletResponse中已有)返回PrintWriter的对象
          * 此方法用来发送字符文本到客户端
          */
         public PrintWriter getWriter(){
             return pw;
         }
     }; 
     /**
      * 在不跳转下访问目标jsp。 就是利用RequestDispatcher.include(ServletRequest request,
      * ServletResponse response)。 该方法把RequestDispatcher指向的目标页面写到response中。
      */
     rd.include(request, resp);
     pw.flush();
     /**
      * 使用ByteArrayOutputStream的writeTo方法来向文本输出流写入数据，这也是为什么要使用ByteArray的一个原因
      */
     baos.writeTo(output);
 }
 

import javax.servlet.ServletContext; //导入方法依赖的package包/类
/**
 * Handle an HTTP status code or Java exception by forwarding control to the
 * location included in the specified errorPage object. It is assumed that
 * the caller has already recorded any request attributes that are to be
 * forwarded to this page. Return <code>true</code> if we successfully
 * utilized the specified error page location, or <code>false</code> if the
 * default error report should be rendered.
 *
 * @param request
 *            The request being processed
 * @param response
 *            The response being generated
 * @param errorPage
 *            The errorPage directive we are obeying
 */
private boolean custom(Request request, Response response, ErrorPage errorPage) {

	if (container.getLogger().isDebugEnabled())
		container.getLogger().debug("Processing " + errorPage);

	try {
		// Forward control to the specified location
		ServletContext servletContext = request.getContext().getServletContext();
		RequestDispatcher rd = servletContext.getRequestDispatcher(errorPage.getLocation());

		if (rd == null) {
			container.getLogger()
					.error(sm.getString("standardHostValue.customStatusFailed", errorPage.getLocation()));
			return false;
		}

		if (response.isCommitted()) {
			// Response is committed - including the error page is the
			// best we can do
			rd.include(request.getRequest(), response.getResponse());
		} else {
			// Reset the response (keeping the real error code and message)
			response.resetBuffer(true);
			response.setContentLength(-1);

			rd.forward(request.getRequest(), response.getResponse());

			// If we forward, the response is suspended again
			response.setSuspended(false);
		}

		// Indicate that we have successfully processed this custom page
		return (true);

	} catch (Throwable t) {
		ExceptionUtils.handleThrowable(t);
		// Report our failure to process this custom page
		container.getLogger().error("Exception Processing " + errorPage, t);
		return (false);

	}
}