Send byte array from PHP to Java Socket

Question

I have a java server listening on a Socket. I can send and receive data between this java server socket and java client sockets attached to it.

Now I want to connect PHP to the java server (via the java socket) but cannot seem to send a byte array (using pack()) to java.

$socket = fsockopen("127.0.0.1", 5477) or die("Error creating socket");

$output = pack("i3", 2, 1, 1); 
fwrite($socket, $output, 3);

On the java end I get a java.io.EOFException when I try to call in.readInt() (where in is a DataInputStream)

if (in.available() != 0)
{
    //read the data
    int len = in.readInt(); //length of the buffer
}

So what is the problem? / Am I going about this in the correct way or is there a better way to do this?

Alexander Pogrebnyak · Accepted Answer · 2011-11-14 22:20:30Z

1

You are writing just 3 bytes to the socket, but readInt() ALWAYS reads 4 bytes to construct java int value.

So, you, naturally, get EOFException after a 3rd byte.

answered Nov 14, 2011 at 22:20

Alexander Pogrebnyak

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2 Comments

Andrew Over a year ago

Oh I see. So I should change it to: fwrite($socket, $output, 12)? And do I need to reverse the bit order in java? (as I now when I read the length I get 33554432)

Alexander Pogrebnyak Over a year ago

@Andrew. Java DataInputStream uses big endian byte order, so if you want to use it you must package the data accordingly on PHP side.

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