Java InputStream.read(byte[], int, int) method, how to block until the exact number of bytes has been read

Question

I\'m writing a simple client/server network application that sends and receives fixed size messages through a TCP socket.

So far, I\'ve been using the <

Answer 1

Use DataInputStream.readFully. Here is JavaDoc

InputStream in = ...
DataInputStream dis = new DataInputStream( in );
byte[] array = ...

dis.readFully( array );

Answer 2

a simple for one-liner will do the trick

int toread = 60;
byte[] buff;
for(int index=0;index<toread;index+=in.read(buff,index,toread-index));

but most of the time the only reason less bytes would be read is when the stream ends or the bytes haven't all been flushed on the other side

Answer 3

I think the correct version of ratchet freak's answer is this :

for (int index = 0; index < toRead && (read = inputStream.read(bytes, index, toRead-index))>0 ; index+= read);

it stops reading if read returns -1

Answer 4

The simple loop is the way to go. Given the very small number of bytes you're exchanging, I guess it will need just one iteration to read everything, but if you want to make it correct, you have to loop.