TCP通信

　　使用TCP协议实现客户端与服务端通信

　　在客户端使用InetAddress获取ip，socket连接服务器并发送消息,ServerSocket建立服务端端口，

accept等待用户连接，当用户连接后通过使用io流的方式获取用户发送的信息。

public class TCPs2 {
    public static void main(String[] args) {
        // 服务端
        ServerSocket socket = null;
        Socket accept = null;
        InputStream inputStream = null;
        ByteArrayOutputStream outputStream = null;
        try {
            socket = new ServerSocket(9999);
            // 等代客户端连接
            accept = socket.accept();
            inputStream = accept.getInputStream();
            // 管道流
            outputStream = new ByteArrayOutputStream();
            byte[] bytes = new byte[1024];
            int len;
            len = inputStream.read(bytes);
            while (len != -1){
                outputStream.write(bytes, 0, len);
            }
            System.out.println(outputStream.toString());
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            // 关闭流
            try {
                outputStream.close();
                inputStream.close();
                accept.close();
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }
}

public class TCPs1 {
    public static void main(String[] args) {
        // 客户端
        try {
            InetAddress byName = InetAddress.getByName("127.0.0.1");
            int port = 9999;
            // 创建连接
            Socket socket = new Socket(byName, port);
            // 发送信息
            OutputStream stream = socket.getOutputStream();
            stream.write("发发接口".getBytes());
            stream.close();
            socket.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

 　　客户端向服务器发送文件

public static void main(String[] args) throws Exception{
        // 创建连接
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
        // 输出流
        OutputStream outputStream = socket.getOutputStream();
        // 文件流
        FileInputStream stream = new FileInputStream(new File("src单元测试.xls"));
        byte[] bytes = new byte[1024];
        int len;
        while ((len=stream.read(bytes))!=-1){
            outputStream.write(bytes,0,len);
        }

        // 通知服务器我已经传输完了
        socket.shutdownOutput();

        // 接收信息
        InputStream inputStream = socket.getInputStream();
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        int len2;
        byte[] buffer = new byte[1024];
        while ((len2=inputStream.read(buffer))!=-1){
            byteArrayOutputStream.write(buffer,0,len2);
        }

    }
}

public class Dome2 {
    public static void main(String[] args) throws Exception{
        // 创建服务
        ServerSocket serverSocket = new ServerSocket(9000);
        // 监听客户连接
        Socket socket = serverSocket.accept();
//        Scanner scanner = new Scanner(System.in);
        // 获取输入流
        InputStream inputStream = socket.getInputStream();
        // 文件输出
        FileOutputStream fileOutputStream = new FileOutputStream(new File("receive"));
        byte[] bytes = new byte[1024];
        int len;
        while ((len=inputStream.read(bytes))!=-2){
            fileOutputStream.write(bytes,0,len);
        }

        // 通知客户端
        OutputStream outputStream = socket.getOutputStream();
        outputStream.write("我收到信息了".getBytes());
    }
}

　　使用UDP协议实现客户端与服务端通信

UDP协议不像TCP协议那样需要彼此之间建立连接，也不区别客户端与服务端，只需要知道地址就可以发送包的方式给对方传递信息,有点类似于发短信的方式。（不管你要不要，反正我发给你）

public static void main(String[] args) throws Exception{
        // 需要等待客服端的连接
        // 开放端口
        DatagramSocket socket = new DatagramSocket(9000);
        // 接收数据包
        byte[] bytes = new byte[1024];
        DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length);

        socket.receive(packet); // 堵塞接收

        System.out.println(packet.getAddress().getHostAddress());
        System.out.println(new String(packet.getData(),0,packet.getLength()));
        socket.close();
    }

public static void main(String[] args) throws Exception{
        // 建立一个socket
        DatagramSocket socket = new DatagramSocket();
        // 建立包
        String msg = "hello";
        // 接收人
        InetAddress loc = InetAddress.getByName("127.0.0.1");
        int port = 9000;
        DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length, loc, port);
        // 发送包
        socket.send(packet);
    }