java web http请求转发

java web，如何获取request中的请求参数呢？

/***
	 * Get request query string
	 * @param request
	 * @return   byte[]
	 */
	public byte[] getRequestStr(HttpServletRequest request){
		int contentLength = request.getContentLength();
		byte buffer[] = new byte[contentLength];
		for (int i = 0; i < contentLength;) {
			try {

				int readlen = request.getInputStream().read(buffer, i,
						contentLength - i);
				if (readlen == -1) {
					break;
				}
				i += readlen;
			} catch (IOException ioexception) {
				ioexception.printStackTrace();
			} finally {
				// logger.info("Json Request:" + requestPacket);
			}
		}
		return buffer;
	}

上述方法返回的是byte数组。

下面的方法直接返回字符串：

/***
	 * Get request query string
	 * 
	 * @param request
	 * @return
	 * @throws UnsupportedEncodingException
	 */
	public String getRequestStr(HttpServletRequest request) throws UnsupportedEncodingException{
		byte buffer[]=getRequestBytes(request);
		String charEncoding=request.getCharacterEncoding();
		if(charEncoding==null){
			charEncoding="UTF-8";
		}
		return new String(buffer,charEncoding);
	}

java web中，重写response应答体（响应体），如何往应答体中写入指定内容呢？

/***
	 * Send http request
	 * 
	 * @param response
	 * @param bytes  :字节数组
	 * @param contentType  :if is null,default value is  "application/json"
	 * @param encoding   ：  编码方式
	 * @throws IOException
	 */
	public static void sendRequestWriter(HttpServletResponse response, byte[] bytes,
			String contentType,String encoding) throws IOException {
		response.setContentLength(bytes.length);
		if (contentType == null) {
			contentType = "application/json";
		}
		response.setContentType(contentType);

		PrintWriter printer = response.getWriter();
		printer.println(new String(bytes,encoding));
		printer.flush();
		printer.close();
	}
	
	/***
	 * 
	 * @param response
	 * @param sendData   :<code>String</code>
	 * @param contentType
	 * @param encoding : such as GBK/utf-8
	 * @throws IOException
	 */
	public static void sendRequestWriter(HttpServletResponse response, String sendData,
			String contentType,String encoding) throws IOException {
//		response.setContentLength(sendData.getBytes(encoding).length);
		byte[]bytes=sendData.getBytes(encoding);
		sendRequestWriter(response, bytes, contentType, encoding);
	}

 以上方法都是使用PrintWriter来写入response的。

下面的方式是使用流的方式写入response：

/***
	 * test ok
	 * @param response
	 * @param bytes
	 * @param contentType
	 * @param encoding
	 * @throws IOException
	 */
	public static void sendRequestStream(HttpServletResponse response, byte[] bytes,
			String contentType) throws IOException {
		response.setContentLength(bytes.length);
		if (contentType == null) {
			contentType = "application/json";
		}
		response.setContentType(contentType);

		ServletOutputStream sos = response.getOutputStream();
		sos.write(bytes, 0, bytes.length);
		sos.flush();
		sos.close();
	}

 应用：用于在网关中进行请求转发和响应。