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技術社區[雲棲]
java web http請求轉發
java web，如何獲取request中的請求參數呢？
/***
* 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數組。
下麵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);
}
應用：上述方法一般用於在filter（javax.servlet.Filter）中獲取請求參數，進行轉發
java web中，重寫response應答體（響應體），如何往應答體中寫入指定內容呢？
/***
* Send http request
*
* @param response
* @param bytes :字節數組
* @param contentType :if is null,default value is "application/json"
* @param encoding ： 編碼方式
* @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來寫入response的。
下麵的方式是使用流的方式寫入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();
}
應用：用於在網關中進行請求轉發和響應。
最後更新：2017-04-03 16:48:56