Socket编程-write（）从Java Servlet到服务器C的固定字节数

需要一些帮助来读取从java客户端到C服务器的确切字节。流动比如说，我想读取前两个字节，然后知道发送的是哪个字符串/总字节数，因此使用recv_函数，该函数将实际字节数作为参数。这样我就可以限制等待时间，而不是读取所有预期的1024个缓冲区大小。还有，我想知道如何从java端发送一个struct，使其整洁。 非常感谢

          //***************  Java Client *****************

        protected void doGet(HttpServletRequest request,
    HttpServletResponse response) throws ServletException, IOException{
        sslsocket.startHandshake();
    kmipoutstream = sslsocket.getOutputStream();
    OutputStreamWriter outputstreamwriter = new OutputStreamWriter(kmipoutstream);

    // figure out what we want to ask for
    final String path = request.getPathInfo();

           System.out.println("request pathInfo: " + path);


    if (path == null || path.endsWith("/users")) {

           //***********SHOULD I SEND 13 FIRST = 2 BYTES?? ***************

                    outputstreamwriter.write("13")
        outputstreamwriter.write("GET ALL USERS");
    } else if (path.endsWith("/keys")) {
        outputstreamwriter.write("GET ALL KEYS");
    } else if (path.endsWith("/templates")) {
        outputstreamwriter.write("GET ALL TEMPLATES");}
    outputstreamwriter.flush();
    BufferedReader wireBufReader = new BufferedReader(
        new InputStreamReader(sslsocket.getInputStream()));

    String tmp = wireBufReader.readLine();

    System.out.println(tmp);
    int numrows = Integer.parseInt(tmp);
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    response.setHeader("Cache-control", "max-age=0");
    response.setHeader("Content-Range", "0-" + numrows + "/" + numrows);

    while (!(tmp = wireBufReader.readLine()).isEmpty()) {
    response.getOutputStream().println(tmp);}
    kmipoutstream.close();
         }

           //**********  Server.C  *******************

           inBuf = calloc(1, 1024);
          if (inBuf == NULL){
      debug_print("ERROR: Memory allocation for inbuf.\n", NULL);
      endProcessing = 1;}
          printf("This is inBuf= %s \n", *inBuf);
             while (!endProcessing){
             sts = RS_SUCCESS;
             do{
            //do accept, followed by negotiate
            sts = rs_ssl_negotiate_viaAccept(rs_ssl_env, IOMODE_NONBLOCKING,
         listenerSocket, &rs_ssl_conn, &ssllog);
          printf("After negotiate and accept sts = %d\n", sts);

          if (RS_SUCCESS != sts){
    debug_print("ERROR: Error during accept and negotiate: %d\n", sts);
    rslog_print(ssllog);
    break;   
  /*
   * receive the get request, parse it out, and call the db method.
   */
  //memset(inBuf, 0, 1024);

   //*******I NEED HELP HERE. NOT SURE HOW TO KNOW THE EXACT NUMBER OF 
                     BYTES BEING SENT BEFORE I CALL
                                     RS_SSL_RECV_EXACTLY ********************

     if( = rs_ssl_recv_exactly(rs_ssl_conn, inBuf, 2, &ssllog)){
      debug_print("ERROR: During HTTP receive: %d\n", sts);
          rslog_print(ssllog);
          break; }
   else
   { if (sts = db_get_userlist_json(jInfo->db_ctx, &jsonBuf, &numrows))
              {debug_print("error getting json user: %d\n", sts);
                break;}}
  __atoe_l(inBuf, actualBytes);
 debug_print("successfully received %d bytes of request:\n<%s>\n", bytesRecvd, inBuf);

   protected void doGet(HttpServletRequest request,
   HttpServletResponse response) throws ServletException, IOException{
         sslsocket.startHandshake();
   kmipoutstream = sslsocket.getOutputStream();
   OutputStreamWriter outputstreamwriter = new OutputStreamWriter(kmipoutstream);

   // figure out what we want to ask for
   final String path = request.getPathInfo();

   System.out.println("request pathInfo: " + path);

   if (path == null || path.endsWith("/users")) {

        // ******** SHOULD I SEND 13 FIRST = 2 BYTES??  ***********

      outputstreamwriter.write("13");
      outputstreamwriter.write("GET ALL USERS");
   } else if (path.endsWith("/keys")) {
      outputstreamwriter.write("GET ALL KEYS");
   } else if (path.endsWith("/templates")) {
      outputstreamwriter.write("GET ALL TEMPLATES");
   }
    outputstreamwriter.flush();
    BufferedReader wireBufReader = new BufferedReader(
         new InputStreamReader(sslsocket.getInputStream()));

    String tmp = wireBufReader.readLine();

    System.out.println(tmp);
    int numrows = Integer.parseInt(tmp);
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    response.setHeader("Cache-control", "max-age=0");
    response.setHeader("Content-Range", "0-" + numrows + "/" + numrows);

    while (!(tmp = wireBufReader.readLine()).isEmpty()) {
        response.getOutputStream().println(tmp);
    }
    kmipoutstream.close();
}

这样我就可以限制等待时间，而不是读取所有预期的1024个缓冲区大小

但recv并不是这样的。它在阻塞模式下阻塞，直到至少有一个字节可用，然后传输任何可用的字节，直到指定的长度。它不会尝试填充缓冲区，除非碰巧有那么多数据可用

---

因此，您的问题根本不存在。

您的代码很难阅读，因为它的缩进和空格的使用到处都是。考虑一下这个问题，这样我们就可以更容易理解了。如果你这样做，你将大大增加获得良好帮助的机会。具体来说，将每个块缩进4个空格，不要使用制表符，避免空行超过1行，并尽量少用空行。好运不，不，你不是。我已经手动修复了您的第一个代码块，以便缩进有意义。请以同样的方式处理其他文件。注释：OutputStreamWriter OutputStreamWriter=new OutputStreamWriter KmiOutStream，StandardCbarsets.UT_8；否则将采用默认服务器的编码。很高兴知道。指定的长度是指发送的确切字节数？所以EJP，我希望我的recv使用发送的确切字节长度。我有3条if语句写入我的C服务器。使用recv，我不知道如何做到这一点。我给recv打两次电话吗？？我很困惑，你必须提前发送长度，然后写一个循环，接收直到你得到这个长度，在你前进的过程中增加偏移参数，减少长度参数。