NIO + multiple packets

Question

How does a web server take multiple packets from a client and make one large request out of it?
I have a NIO server which until now has always assumed "requests" were being sent with one packet. Thus, I built my code to always assume each request = one read from the selection key = one action I take.
For example, if I sent "hello there server" as a command, the server would parse "hello there server" and I would execute some return logic based on that request.
Now I have very long requests that are being received as multiple packets. For example "hello there server blah blah blah" is being recieved as "hello there server" (packet 1) and then "blah blah blah" (packet 2). (just humor me, it happens with longer requests than that ;-)
I assume this happens a lot with http servers - So how do I put multiple packets "together" in NIO? Would I store the contents of each packet into memory until the last packet of a request arrives, then parse the request? Thanks!

Answer 1

If your packets are character strings you can use the fact that CharBuffer implements CharSequence and can be used much like a StringBuffer. See the code example below. Otherwise you could just keep a ByteBuffer and copy the data from using put.
Here's the example for strings, the rest of this application is in my post Taming the NIO Circus
     // reception support
     // receive a string
     private void doRead()
          String dat;
          while(null != (dat = readLine()))client.fromRemote(dat); // send it back to the client
          if(atEof)close();
     private String readLine()
          String s = null;
          fill();
          int len = recvString.length();
          int n = firstNL();
          if(n == -1)
               if(atEof && 0 < len)
                    s = recvString.substring(0);
                    n = len;
          else
               s = recvString.substring(0,n);
               if(len > n+1 && recvString.charAt(n)=='\r' && recvString.charAt(n+1)=='\n')n+=2;
               else n++;
          if(n > 0)
               recvString.delete(0,n);
               recvScanned = 0;
          return s;
     public boolean fill()
          CharBuffer buf;
          int len=0;
          recvBuffer.clear();
          try{len = sch.read(recvBuffer);}
          catch(Exception e){e.printStackTrace();atEof=true;}
          recvBuffer.flip();
          if(len > 0)
               dout(1,"read "+len+" bytes");
               try
                    buf = decoder.decode(recvBuffer);
                    dout(0,"received="+buf);
                    recvString.append(buf);
               catch(Exception e){e.printStackTrace();atEof = true;}
          else if(len < 0)atEof = true;
          return atEof;
     // scan recvString for first new line
     private int firstNL()
          while(recvScanned < recvString.length())
               char ch = recvString.charAt(recvScanned);
               if(ch == '\r' || ch == '\n')return recvScanned;
               recvScanned++;
          return -1;     // no cr or lf
     }