java网络编程基础

public class TcpEchoClient {
    private static final String serverIP = "127.0.0.1";
    private static final int port = 8888;

    public static void main(String[] args) {
        byte[] writeData = "hi".getBytes();
        byte[] revdData = new byte[writeData.length];
        Socket socket = null;
        try {
            // 创建一个Socket实例
            socket = new Socket(serverIP, port);

            // 进行通信
            InputStream in = socket.getInputStream();
            OutputStream out = socket.getOutputStream();
            out.write(writeData);
            socket.shutdownOutput();
            System.out.println("client send " + new String(writeData));

            in.read(revdData);
            System.out.println("client recived " + new String(revdData));
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭连接
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

public class TcpEchoServer {
    private static final int port = 8888;

    public static void main(String[] args) throws InterruptedException,
            IOException {
        ServerSocket server = new ServerSocket(port);
        while (true) {
            // 阻塞直到有客户端进行连接
            Socket socket = server.accept();
            InputStream in = socket.getInputStream();
            OutputStream out = socket.getOutputStream();

            byte[] data = new byte[1024];
            int len = in.read(data)；
            out.write(data, 0, len);
            System.out.println("Server recived " + new String(data, 0, len));
            socket.close();
        }

    }
}

public class EchoProtocal implements Runnable{
    private Socket socket;

    public EchoProtocal(Socket socket) {
        this.socket = socket;
    }

    public void handle() {
        try {
            InputStream in = socket.getInputStream();
            OutputStream out = socket.getOutputStream();

            byte[] data = new byte[1024];
            int len =  in.read(data);
            out.write(data， 0， len);
            System.out.println(Thread.currentThread().getName() + "server reviced " + new String(data, 0, len));

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void run() {
        handle();
    }

}

public class EchoProtocalTestServer {
    public static void main(String[] args) throws IOException {
        ServerSocket server = new ServerSocket(8888);

        /*while (true) {
            EchoProtocal ep = new EchoProtocal(server.accept());
            new Thread(ep).start();
        }*/

        Executor service = Executors.newCachedThreadPool();
        while (true) {
            EchoProtocal ep = new EchoProtocal(server.accept());
            service.execute(ep);
        }
    }
}

public class TcpEchoClientNoblocking {
    private static final String ADDRESS = "127.0.0.1";
    private static final int PORT = 8888;

    public static void main(String[] args) throws IOException {
        SocketChannel clntChan = SocketChannel.open();
        clntChan.configureBlocking(false);// 设置非阻塞

        InetSocketAddress isa = new InetSocketAddress(ADDRESS, PORT);
        if (!clntChan.connect(isa)) {
            while (!clntChan.finishConnect()) {
                System.out.println("连接中。。");
            }
        }

        byte[] sendBytes = "HelloWorld".getBytes();
        ByteBuffer writeBuf = ByteBuffer.wrap(sendBytes);
        clntChan.write(writeBuf);
        System.out.println("client send " + new String(sendBytes));

        ByteBuffer readBuf = ByteBuffer.allocate(sendBytes.length);
        int totalBytesRcvd = 0;
        int bytesRcvd;
        while (totalBytesRcvd < sendBytes.length) {
            bytesRcvd = clntChan.read(readBuf);
            if (bytesRcvd != -1) {
                totalBytesRcvd += bytesRcvd;
            }

        }

        System.out.println("client recived " + new String(readBuf.array(), 0, totalBytesRcvd));
    }
}


public class TCPEchoServerNoBlocking {

    private static final int PORT = 8888;

    public void start() throws IOException {
        Selector selector = Selector.open();

        ServerSocketChannel serverChan = ServerSocketChannel.open();

        serverChan.socket().bind(new InetSocketAddress(PORT));
        serverChan.configureBlocking(false);
        serverChan.register(selector, SelectionKey.OP_ACCEPT);

        while (true) {
            if (selector.select(3000) == 0) {
                // 无连接
                System.out.println("等待连接...");
                continue;
            }

            Iterator<SelectionKey> keyIter = selector.selectedKeys().iterator();
            while (keyIter.hasNext()) {
                SelectionKey key = keyIter.next();
                try {
                    handleInput(key);
                } catch (Exception e) {
                    if (key != null) {
                        key.cancel();
                        if (key.channel() != null) {
                            key.channel().close();
                        }
                    }
                } finally {
                    keyIter.remove();
                }

            }

        }
    }

    private void handleInput(SelectionKey key) throws IOException {
        if (key.isAcceptable()) {
            // 可连接
            SocketChannel clntChanAccept = ((ServerSocketChannel) key.channel())
                    .accept();
            clntChanAccept.configureBlocking(false);

            clntChanAccept.register(key.selector(), SelectionKey.OP_READ,
                    ByteBuffer.allocate(1024));
        }

        if (key.isReadable()) {
            // 可读
            SocketChannel sc = (SocketChannel) key.channel();
            ByteBuffer bufRead = (ByteBuffer) key.attachment();
            int readBytes = sc.read(bufRead);

            if (readBytes > 0) {
                bufRead.flip();
                byte[] bytes = new byte[bufRead.remaining()];
                bufRead.get(bytes);
                String body = new String(bytes);
                System.out.println("server received : " + body);

                //echo
                doWrite(sc, body);
            } else if (readBytes < 0) {
                // 读完
                key.cancel();
                sc.close();
            } else {
                // 读到0字节
            }
        }
        if (key.isValid() && key.isWritable()) {

            // 可写
            ByteBuffer bufWrite = (ByteBuffer) key.attachment();
            bufWrite.flip();
            SocketChannel clntChanWrite = (SocketChannel) key.channel();
            clntChanWrite.write(bufWrite);
            // clntChanWrite.close();
            // 是否还有剩余字节
            if (!bufWrite.hasRemaining()) {
                // 无数据,使key只能进行读操作
                key.interestOps(SelectionKey.OP_READ);
            }

            // 压缩缓冲区 执行完该操作缓冲区变为可读
            bufWrite.compact();
        }

    }

    private void doWrite(SocketChannel channel, String response) throws IOException {
        if (response != null && response.trim().length() > 0) {
            byte[] bytes = response.getBytes();
            ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
            writeBuffer.put(bytes);
            writeBuffer.flip();
            channel.write(writeBuffer);
        }
    }

    public static void main(String[] args) throws Exception  {
        new TCPEchoServerNoBlocking().start();
    }
}