基于Socket的TCP网络编程

基于Socket的TCP编程

Java语言的基于套接字编程分为服务端编程和客户端编程，其通信模型如图所示：

客户端Socket的工作过程

1. 创建Socket对象，指明服务器端的ip和端口号。
2. 获取一个输出流，用于输出数据。
3. 写出数据的操作。
4. 资源的关闭。

服务器端ServerSocket的工作过程

1. 创建服务器端的ServerSocket，指明自己的端口号。
2. 调用accept()表示接收来自于客户端的socket。
3. 获取输入流。
4. 读取输入流中的数据。
5. 关闭资源。

示例一：客户端发送信息给服务端，服务端将数据显示在控制台上。

@Test
    public void client(){
        Socket socket = null;
        OutputStream outputStream = null;
        try {
        	// 1. 创建Socket对象，指明服务器端的ip和端口号。
            InetAddress inetAddress = InetAddress.getByName("127.0.0.1");
            socket = new Socket(inetAddress,8088);
            // 2. 获取一个输出流，用于输出数据。
            outputStream = socket.getOutputStream();
            // 3. 写出数据的操作。
            outputStream.write("客户端发送消息".getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
        	// 4. 资源的关闭
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            try {
                if (socket != null)
                    socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }


    }
    @Test
    public void server(){
        ServerSocket serverSocket = null;
        Socket accept = null;
        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        ByteArrayOutputStream byteArrayOutputStream = null;
        try {
        	//1.创建服务器端的ServerSocket，指明自己的端口号
            serverSocket = new ServerSocket(8088);
			//2.调用accept()表示接收来自于客户端的socket
            accept = serverSocket.accept();
			//3.获取输入流
            inputStream = accept.getInputStream();
			//4.读取输入流中的数据
            inputStreamReader = new InputStreamReader(inputStream,"utf-8");

//            //方式一：因为inputStream是字节型输入流，所以使用ByteArrayOutputStream解决乱码问题
//            byteArrayOutputStream = new ByteArrayOutputStream();
//            byte[] buffer = new byte[5];
//            int len;
//            while ((len = inputStream.read(buffer)) != -1){
//                byteArrayOutputStream.write(buffer,0,len);
//
//            }
//            System.out.println(byteArrayOutputStream.toString());

            //方式二：使用转换流inputStreamReader解决乱码问题
            char[] cbuf = new char[5];
            int len;
            while ((len = inputStreamReader.read(cbuf)) != -1){
                String str = new String(cbuf,0,len);
                System.out.print(str);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
        	//5.关闭资源
            try {
                if (byteArrayOutputStream != null)
                    byteArrayOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (inputStreamReader != null)
                    inputStreamReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (inputStream != null)
                    inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (accept != null)
                    accept.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (serverSocket != null)
                    serverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
           

输出结果：

示例二：客户端发送文件给服务端，服务端将文件保存在本地。

public class TCPTest2 {
    @Test
    public void client(){
        Socket socket = null;
        OutputStream outputStream = null;
        FileInputStream fileInputStream = null;
        BufferedInputStream bufferedInputStream= null;
        try {
            InetAddress inetAddress = InetAddress.getByName("127.0.0.1");

            socket = new Socket(inetAddress,8099);

            outputStream = socket.getOutputStream();

            fileInputStream = new FileInputStream(new File("04.PNG"));

            bufferedInputStream = new BufferedInputStream(fileInputStream);

            byte[] buffer = new byte[10];
            int len;
            while ((len = bufferedInputStream.read(buffer)) != -1){
                outputStream.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedInputStream != null)
                    bufferedInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (fileInputStream != null)
                    fileInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (outputStream != null)
                    outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (socket != null)
                    socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }


    }

    @Test
    public void server(){
        ServerSocket serverSocket = null;
        Socket accept = null;
        InputStream inputStream = null;
        FileOutputStream fileOutputStream = null;
        BufferedOutputStream bufferedOutputStream = null;
        try {
            serverSocket = new ServerSocket(8099);

            accept = serverSocket.accept();

            inputStream = accept.getInputStream();

            fileOutputStream = new FileOutputStream("08.PNG");

            bufferedOutputStream = new BufferedOutputStream(fileOutputStream);

            byte[] buffer = new byte[10];
            int len;
            while((len = inputStream.read(buffer)) != -1){
                bufferedOutputStream.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedOutputStream != null)
                    bufferedOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (fileOutputStream != null)
                    fileOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (inputStream != null)
                    inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (accept != null)
                    accept.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (serverSocket != null)
                    serverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}
           

示例三：从客户端发送文件给服务端，服务端保存到本地。并返回“发送成功”给客户端。并关闭相应的连接。

public class TCPTest3 {
    @Test
    public void client(){
        Socket socket = null;
        OutputStream outputStream = null;
        FileInputStream fileInputStream = null;
        BufferedInputStream bufferedInputStream= null;
        InputStream inputStream = null;
        ByteArrayOutputStream byteArrayOutputStream = null;
        try {
            InetAddress inetAddress = InetAddress.getByName("127.0.0.1");

            socket = new Socket(inetAddress,8099);

            outputStream = socket.getOutputStream();

            fileInputStream = new FileInputStream(new File("04.PNG"));

            bufferedInputStream = new BufferedInputStream(fileInputStream);

            byte[] buffer = new byte[10];
            int len;
            while ((len = bufferedInputStream.read(buffer)) != -1){
                outputStream.write(buffer,0,len);
            }
            //关闭数据的输出
            socket.shutdownOutput();

            //接收来自服务器端的反馈
            inputStream = socket.getInputStream();
            byteArrayOutputStream = new ByteArrayOutputStream();
            byte[] buffer1 = new byte[20];
            int len1;
            while ((len = inputStream.read(buffer)) != -1){
                byteArrayOutputStream.write(buffer,0,len);
            }
            System.out.println(byteArrayOutputStream.toString());

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (inputStream != null)
                    inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (byteArrayOutputStream != null)
                    byteArrayOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (bufferedInputStream != null)
                    bufferedInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (fileInputStream != null)
                    fileInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (outputStream != null)
                    outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (socket != null)
                    socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }


    }

    @Test
    public void server(){
        ServerSocket serverSocket = null;
        Socket accept = null;
        InputStream inputStream = null;
        FileOutputStream fileOutputStream = null;
        BufferedOutputStream bufferedOutputStream = null;
        OutputStream outputStream = null;
        try {
            serverSocket = new ServerSocket(8099);

            accept = serverSocket.accept();

            inputStream = accept.getInputStream();

            fileOutputStream = new FileOutputStream("09.PNG");

            bufferedOutputStream = new BufferedOutputStream(fileOutputStream);

            byte[] buffer = new byte[10];
            int len;
            while((len = inputStream.read(buffer)) != -1){
                bufferedOutputStream.write(buffer,0,len);
            }

            //服务器端接收成功，给予客户端反馈
            outputStream = accept.getOutputStream();
            outputStream.write("数据已接收！".getBytes());

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (outputStream != null)
                    outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (bufferedOutputStream != null)
                    bufferedOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (fileOutputStream != null)
                    fileOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (inputStream != null)
                    inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (accept != null)
                    accept.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (serverSocket != null)
                    serverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}