Java Community | Help. Code. Learn.•9mo ago

Java Socket NIO Reading Issue

(code in comments) I have a server and a client. I am trying to transmit a long from the server to the client (or reverse, neither works). I can tell it is transmitting, but the reciever gets hung up on the socket.read(buf) line in readLong. Please help. I just started NIO this morning and have no clue if I'm doing it right.

3 Replies

JavaBot•9mo ago

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The TyphothanianOP•9mo ago

package net.typho.utils.nio;

import java.io.Closeable;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.List;

public class ChannelHandler implements Closeable {
    public final SocketChannel socket;

    public ChannelHandler(SocketChannel socket) {
        this.socket = socket;
    }

    @Override
    public String toString() {
        try {
            return socket.getRemoteAddress().toString();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public void close() throws IOException {
        socket.close();
    }

    public void write(byte... data) throws IOException {
        ByteBuffer buf = ByteBuffer.wrap(data).flip();

        while (buf.hasRemaining()) {
            socket.write(buf);
        }
    }

    public void write(long... data) throws IOException {
        ByteBuffer buf = ByteBuffer.allocate(data.length * Long.BYTES);

        for (long l : data) {
            buf.putLong(l);
        }

        buf.flip();

        while (buf.hasRemaining()) {
            System.out.println(socket.write(buf));
        }
    }

package net.typho.utils.nio;

import java.io.Closeable;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.List;

public class ChannelHandler implements Closeable {
    public final SocketChannel socket;

    public ChannelHandler(SocketChannel socket) {
        this.socket = socket;
    }

    @Override
    public String toString() {
        try {
            return socket.getRemoteAddress().toString();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public void close() throws IOException {
        socket.close();
    }

    public void write(byte... data) throws IOException {
        ByteBuffer buf = ByteBuffer.wrap(data).flip();

        while (buf.hasRemaining()) {
            socket.write(buf);
        }
    }

    public void write(long... data) throws IOException {
        ByteBuffer buf = ByteBuffer.allocate(data.length * Long.BYTES);

        for (long l : data) {
            buf.putLong(l);
        }

        buf.flip();

        while (buf.hasRemaining()) {
            System.out.println(socket.write(buf));
        }
    }

    public List<Byte> read() throws IOException {
        List<Byte> bytes = new ArrayList<>();
        ByteBuffer buf = ByteBuffer.allocate(16);

        while (socket.read(buf) > 0) {
            buf.flip();

            while (buf.hasRemaining()) {
                bytes.add(buf.get());
            }

            buf.clear();
        }

        return bytes;
    }

    public List<Long> readLong() throws IOException {
        List<Long> longs = new ArrayList<>();
        ByteBuffer buf = ByteBuffer.allocate(Long.BYTES);

        while (socket.read(buf) > 0) {
            buf.flip();

            longs.add(((buf.get() & 0xFFL) << 56) |
                    ((buf.get() & 0xFFL) << 48) |
                    ((buf.get() & 0xFFL) << 40) |
                    ((buf.get() & 0xFFL) << 32) |
                    ((buf.get() & 0xFFL) << 24) |
                    ((buf.get() & 0xFFL) << 16) |
                    ((buf.get() & 0xFFL) << 8) |
                    ((buf.get()) & 0xFFL));

            buf.clear();
        }

        return longs;
    }
}

    public List<Byte> read() throws IOException {
        List<Byte> bytes = new ArrayList<>();
        ByteBuffer buf = ByteBuffer.allocate(16);

        while (socket.read(buf) > 0) {
            buf.flip();

            while (buf.hasRemaining()) {
                bytes.add(buf.get());
            }

            buf.clear();
        }

        return bytes;
    }

    public List<Long> readLong() throws IOException {
        List<Long> longs = new ArrayList<>();
        ByteBuffer buf = ByteBuffer.allocate(Long.BYTES);

        while (socket.read(buf) > 0) {
            buf.flip();

            longs.add(((buf.get() & 0xFFL) << 56) |
                    ((buf.get() & 0xFFL) << 48) |
                    ((buf.get() & 0xFFL) << 40) |
                    ((buf.get() & 0xFFL) << 32) |
                    ((buf.get() & 0xFFL) << 24) |
                    ((buf.get() & 0xFFL) << 16) |
                    ((buf.get() & 0xFFL) << 8) |
                    ((buf.get()) & 0xFFL));

            buf.clear();
        }

        return longs;
    }
}

Tried simply sending a byte, no luck

JavaBot•9mo ago

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Java Socket NIO Reading Issue