网络协议

TCP协议

使用TCP协议前，须先建立TCP连接，形成传输数据通道
传输前，采用“三次握手”方式，点对点通信，是可靠的
TCP协议进行通信的两个应用进程：客户端、服务端
在连接中可进行大数据量的传输
传输完毕，需释放已建立的连接，效率低

UDP协议

将数据、源、目的封装成数据包，不需要建立连接
每个数据报的大小限制在64k内
发送不管对方是否准备好，接收方收到也不确认，是不可靠的
可以广播发送
发送数据结束时，无需释放资源，开销小，速度快

TCP网络编程例题1

客户端发送信息给服务端，服务端将信息显示在控制台上

客户端代码：

@Test
public void client(){
    Socket socket = null;
    OutputStream os = null;
    try {

        //1、创建socket对象，指明服务器端的ip和端口号
        InetAddress inet = InetAddress.getByName("127.0.0.1");
        socket = new Socket(inet, 60000);

        //2、获取一个输出流，用于输出数据
        os = socket.getOutputStream();

        //3、写出数据的操作
        os.write("你好！我是客户端".getBytes());

    } catch (IOException e) {
        e.printStackTrace();
    } finally {

        //4、关闭资源流
        if (os != null) {
            try {
                os.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (socket != null) {
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}

服务端代码：

@Test
    public void server(){
        ServerSocket serverSocket = null;
        Socket socket = null;
        InputStream is = null;
        ByteArrayOutputStream baos = null;
        try {

            //1、创建服务器端的ServerSocket，指明自己的端口号
            serverSocket = new ServerSocket(60000);

            //2、调用accept()方法表示接受来自于客户端的socket
            socket = serverSocket.accept();

            //3、获取一个输入流
            is = socket.getInputStream();

            //不建议这么写，有乱码
//            byte[] buffer = new byte[20];
//            int len;
//            while ((len = is.read(buffer)) != -1){
//                String str = new String(buffer, 0, len);
//                System.out.print(str);
//            }

            //4、读取输入流中的数据
            baos = new ByteArrayOutputStream();
            byte[] buffer = new byte[5];
            int len;
            while ((len = is.read(buffer)) != -1){
                baos.write(buffer, 0, len);
            }
            System.out.println(baos.toString());

            System.out.println("收到了来自于：" + socket.getInetAddress().getHostAddress() + "的数据");


        } catch (IOException e) {
            e.printStackTrace();
        } finally {

            //5、关闭资源流
            if (baos != null) {
                try {
                    baos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (serverSocket != null) {
                try {
                    serverSocket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }



    }

TCP网络编程例题2

客户端发送文件给服务端，服务端将文件保存在本地

客户端代码：

@Test
public void client(){
    Socket socket = null;
    OutputStream os = null;
    FileInputStream fis = null;
    try {
        socket = new Socket(InetAddress.getByName("127.0.0.1"), 9090);
        os = socket.getOutputStream();
        fis = new FileInputStream(new File("pic.jpg"));
        byte[] buffer = new byte[1024];
        int len;
        while ((len = fis.read(buffer)) != -1){
            os.write(buffer, 0 ,len);
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (fis != null) {
            try {
                fis.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (os != null) {
            try {
                os.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (socket != null) {
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}

服务端代码：

@Test
public void server(){
    ServerSocket serverSocket = null;
    Socket socket = null;
    InputStream is = null;
    FileOutputStream fos = null;
    try {
        serverSocket = new ServerSocket(9090);
        socket = serverSocket.accept();
        is = socket.getInputStream();
        fos = new FileOutputStream(new File("pic_server.jpg"));

        byte[] buffer = new byte[1024];
        int len;
        while ((len = is.read(buffer)) != -1){
            fos.write(buffer, 0, len);
        }
        System.out.println("接受成功！");
        
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (fos != null) {
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (is != null) {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (socket != null) {
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (serverSocket != null) {
            try {
                serverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}

TCP网络编程例题3

客户端给服务端发送文件，服务端接受文件保存到本地，并返回发送成功的反馈

客户端代码：

@Test
public void client(){
    Socket socket = null;
    OutputStream os = null;
    FileInputStream fis = null;
    ByteArrayOutputStream baos = null;
    try {
        socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
        os = socket.getOutputStream();
        fis = new FileInputStream(new File("pic.jpg"));
        byte[] buffer = new byte[1024];
        int len;
        while ((len = fis.read(buffer)) != -1){
            os.write(buffer, 0 ,len);
        }
        //关闭数据的输出
        socket.shutdownOutput();

        //接受来自于服务器端的数据，并显示到控制台上
        InputStream is = socket.getInputStream();
        baos = new ByteArrayOutputStream();
        byte[] buffer_ = new byte[20];
        int len_is;
        while ((len_is = is.read(buffer_)) != -1){
            baos.write(buffer_, 0, len_is);
        }
        System.out.println(baos.toString());


    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (baos != null) {
            try {
                baos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (fis != null) {
            try {
                fis.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (os != null) {
            try {
                os.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (socket != null) {
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}

服务端代码：

@Test
public void server(){
    ServerSocket serverSocket = null;
    Socket socket = null;
    InputStream is = null;
    FileOutputStream fos = null;
    OutputStream os = null;
    try {
        serverSocket = new ServerSocket(9000);
        socket = serverSocket.accept();
        is = socket.getInputStream();
        fos = new FileOutputStream(new File("pic_server2.jpg"));

        byte[] buffer = new byte[1024];
        int len;
        while ((len = is.read(buffer)) != -1){
            fos.write(buffer, 0, len);
        }

        System.out.println("服务器收到来自："
                + "主机名【" + InetAddress.getLocalHost().getHostName() + "】，"
                + "ip地址【" + InetAddress.getLocalHost().getHostAddress() + "】"
                + "的文件");
        //服务器端给予客户端反馈
        os = socket.getOutputStream();
        os.write("服务器已接收！".getBytes());

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (os != null) {
            try {
                os.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (fos != null) {
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (is != null) {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (socket != null) {
            try {
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (serverSocket != null) {
            try {
                serverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}

UDP网络编程例题（了解即可）

发送端代码：

//发送端
@Test
public void sender(){
    DatagramSocket socket = null;
    try {
        socket = new DatagramSocket();

        InetAddress inet = InetAddress.getLocalHost();

        String str = "UDP方式";
        byte[] data = str.getBytes();
        DatagramPacket packet = new DatagramPacket(data, 0, data.length, inet, 9090);

        socket.send(packet);
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (socket != null)
        socket.close();
    }

}

接收端代码：

//接收端
@Test
public void receiver(){
    DatagramSocket socket = null;
    try {
        socket = new DatagramSocket(9090);

        byte[] buffer = new byte[100];
        DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);

        socket.receive(packet);

        System.out.println(new String(packet.getData(), 0, packet.getLength()));
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (socket != null)
        socket.close();
    }


}

posted @ 2021-11-20 13:31 叁玖贰拾柒阅读(7) 评论(0) 收藏举报

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网络协议

网络协议

TCP协议

UDP协议

TCP网络编程例题1

TCP网络编程例题2

TCP网络编程例题3

UDP网络编程例题（了解即可）

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