CURL：客户端和服务器通信Windows c / java

Question

I am relatively new at curl and I am trying to do a Client in C which sends strings using curl. On the other side, as a Server, I have a Java program which is listening to HTTP requests using HttpServlet. When I send with curl some data I see that the server gets it but not in the format that was sent. For example if I am sending data: "8D015678" In server side Request content will be: 56, 68, 48, 49, 53, 54, 55, 56 Here is Client code(c):

int status = 0;
char * ip_to_connect = "http://127.0.0.1:5004/unilateral
const char * request = "8D015678";
status = curl_easy_setopt(curl, CURLOPT_URL, ip_to_connect);

if (!status)
{
    status = curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &writeCallback);
}
if (!status)
{
    curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long) strlen(request));
}
if (!status)
{
    status =  curl_easy_setopt(curl, CURLOPT_POSTFIELDS, request);
}
if (!status)
{
    status = curl_easy_perform(curl);
}

Here is parser code of Server(java):

   System.out.println("[requestHandlerFactory] header is not Content");
    int contentLength = request.getContentLength();
    this.content = new byte[contentLength];
    try {
        ServletInputStream input = request.getInputStream();
        int read = input.read(content, 0, contentLength);
        System.out.println("[doPost] contentLength = " + contentLength + "data = " + content[0]);

Does this mean that I need to have a convertor from ASCI to symbol? I thought in curl data is passed as is? What am I missing? If I want my data, eg. 8D015678 to be gotten by server as 8D015678 how shall I send it? Please some explanation on how data is passed and how to dealwith client in curl and server receiving those requests Thanks in advance. Hope it is clear

Answer 1

InputStream.read(..) returns -1 when the stream has ended, otherwise the value can be trivially converted to an char. This combination of return value and error code is old and rather unfortunate and would have been designed differently today. Just convert it to a char and process it.

The official documentation is at https://docs.oracle.com/javase/7/docs/api/java/io/InputStream.html#read()

See http://www.tutorialspoint.com/java/io/inputstream_read.htm for a working example.

The essence is:

  // new input stream created
         is = new FileInputStream("C://test.txt");

         System.out.println("Characters printed:");

         // reads till the end of the stream
         while((i=is.read())!=-1)
         {
            // converts integer to character
            c=(char)i;

            // prints character
            System.out.print(c);
         }