How to send data via HTTP get in Java? - http

Question

So, I am going to connect to a servlet via an iphone and use HTTP. I am actually developing a multiplayer game and would like to know how I can send specific data to the iphone via HTTP get in java (doGet). I am using libcurl on the iphone (cocos2d-x).
Here is how my code is set up:
size_t write_data(void* buffer, size_t size, size_t nmemb, void *data)
{
//do stuff with data
}
//main or some init method
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl)
{
char *data = "hi imma get=yeah";
curl_easy_setopt(curl, CURLOPT_URL, "http://whatever.com");
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
res = curl_easy_perform(curl);
if(res != CURLE_OK)
{
CCLOG("WELP BETTER DO SOMETHING ERROR");
}
curl_easy_cleanup(curl);
}
So, what I would like to know is how I can use the response in the doGet method in java to send a string to that write_function defined above? As in, what do I do with response parameter in the doGet method?
For reference here is the doGet method:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
System.out.println("GET METHOD CALLED");
}
So, now what do I do with that response to pass some data to the write_function?
Thanks, for any and all input!!

Answer 1

By using response's Writer, as shown below.
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
// tell response what format your output is in, we select plain text here
response.setContentType("text/plain;charset=UTF-8");
// ask the response object for a Writer object
PrintWriter out = response.getWriter();
try {
// and use it like you would use System.out. Only, this stuff gets sent
//to the client
out.println("GET METHOD CALLED");
} finally {
// housekeeping: ensure that the Writer is closed when you're ready.
out.close();
}
}
In some cases it's easier to use a Stream. That's also possible but you can never have both the Writer and the OutputStream open simultaneously.
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
response.setContentType("text/plain;charset=UTF-8");
// ask the response object for an OutputStream object
OutputStream os = response.getOutputStream();
try {
// output some stuff, here just the characters ABC
os.write(new byte[]{65,66,67});
} finally {
os.close();
}
}
If you want to know more, there are loads of tutorials about servlets available on the web, including the Servlet chapter of the official Java EE tutorial on oracle.com