spring MVC 获取请求体

在spring  MVC中如何获取请求体呢?

在spring MVC中如何获取请求要素呢?

通过如下方法:

/**
	 * Compatible with GET and POST
	 * 
	 * @param request
	 * @return : <code>String</code>
	 * @throws IOException
	 */
	public static String getRequestQueryStr(HttpServletRequest request,
			String charEncoding) throws IOException {
		String submitMehtod = request.getMethod();
		if (submitMehtod.equalsIgnoreCase("post")) {
			byte[] bytes = getRequestPostBytes(request);
			String charEncoding2 = request.getCharacterEncoding();// charset
			System.out.println("[getRequestQueryStr]charEncoding:"
					+ charEncoding2);
			System.out.println("[getRequestQueryStr]Content-Type:"
					+ request.getHeader(Constant2.REQUEST_HEADER_CONTENT_TYPE));

			if(ValueWidget.isNullOrEmpty(charEncoding)){
				charEncoding=SystemHWUtil.CHARSET_UTF;
			}
			return new String(bytes, charEncoding);
		} else {// form method :Get
			return request.getQueryString();
		}
	}

 对GET请求的参数是没有问题的,但是对于POST请求获取不到为什么呢?

因为spring MVC已经获取了一遍request的stream,所以再次获取时是为空的,(这是输入流的特性,可以查查官网API),所以我获取到request 的InputStream之后调用reset,但是报错,不支持reset操作.

怎么办呢?

在spring MVC 的控制器中使用@RequestBody 注解,作用是获取请求体,格式是字节数组,见代码

@ResponseBody
	@RequestMapping(value = "/jsonStub", produces = SystemHWUtil.RESPONSE_CONTENTTYPE_JSON_UTF)
	public String json(Model model, HttpSession session,@RequestBody byte[]bytes,
			HttpServletRequest request, String callback) throws IOException {
		Map map=WebServletUtil.parseRequest(request, null);
		if(ValueWidget.isNullOrEmpty(map)){
			String postStr=new String(bytes,SystemHWUtil.CURR_ENCODING);//username=huangwei&password=123
			System.out.println("postStr:"+postStr);//username=%E9%BB%84%E5%A8%81&password=123
			postStr=URLDecoder.decode(postStr,SystemHWUtil.CURR_ENCODING);//{"username":"黄威","password":"123"}
			map=WebServletUtil.parseRequestStr(postStr, true);
		}
		String content = HWUtils.getJsonP(map, callback);
		return content;
	}

@RequestBody后紧跟的参数将被注入请求体的字节数组(spring mVC帮我们完成的).

注意:request.getInputStream() 读取一次之后,再次读取就读取不到

上述代码依赖的方法:

/***
	 * Get request query string, form method : post
	 * 
	 * @param request
	 * @return byte[]
	 * @throws IOException
	 */
	public static byte[] getRequestPostBytes(HttpServletRequest request)
			throws IOException {
		int contentLength = request.getContentLength();
		/*当无请求参数时，request.getContentLength()返回-1 */
		if(contentLength<0){
			return null;
		}
		byte buffer[] = new byte[contentLength];
		for (int i = 0; i < contentLength;) {

			int readlen = request.getInputStream().read(buffer, i,
					contentLength - i);
			if (readlen == -1) {
				break;
			}
			i += readlen;
		}
		return buffer;
	}

	/***
	 * Get request query string, form method : post
	 * 
	 * @param request
	 * @return
	 * @throws IOException
	 */
	public static String getRequestPostStr(HttpServletRequest request)
			throws IOException {
		byte buffer[] = getRequestPostBytes(request);
		String charEncoding = request.getCharacterEncoding();
		if (charEncoding == null) {
			charEncoding = "UTF-8";
		}
		return new String(buffer, charEncoding);
	}

参考:http://json20080301.iteye.com/blog/1874074?utm_source=tuicool