java网络编程示例

1.client

import java.io.*;
import java.net.InetAddress;
import java.net.Socket;

public class TcpClientDemo {
    public static void main(String[] args) {
        InetAddress byName = null;
        Socket socket = null;
        OutputStream os = null;
        FileInputStream fis = null;
        InputStream is = null;
        ByteArrayOutputStream baos = null;
        try {
            // 1. 获取服务器地址和端口
            byName = InetAddress.getByName("127.0.0.1");
            int port = 9999;

            // 2. 创建socket
            socket = new Socket(byName, port);

            // 3. 读取文件
            os = socket.getOutputStream();
            fis = new FileInputStream(new File("example.jpg"));
            byte[] buffer = new byte[1024];
            int len;
            while ((len = fis.read(buffer)) != -1) {
                os.write(buffer, 0, len);
            }

            // 4. 通知服务器传输结束
            socket.shutdownOutput();

            // 5. 接受服务器传输完毕会话后，才断开连接
            is = socket.getInputStream();
            baos = new ByteArrayOutputStream();
            int len2;
            byte[] buffer2 = new byte[1024];
            while ((len2 = is.read(buffer2)) != -1) {
                baos.write(buffer2, 0, len2);
            }
            System.out.println(baos);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                os.close();
                fis.close();
                is.close();
                baos.close();
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }
}

2.server

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.StandardCharsets;


public class TcpServerDemo {
    public static void main(String[] args) {
        ServerSocket serverSocket = null;
        InputStream is = null;
        Socket socket = null;
        OutputStream os = null;
        FileOutputStream baos = null;

        try {
            // 1. 创建server端
            serverSocket = new ServerSocket(9999);

            // 2.阻塞式监听
            socket = serverSocket.accept();

            // 3.读取客户端的消息
            is = socket.getInputStream();

            // 4.管道流
            baos = new FileOutputStream(new File("receive.jpg"));
            // 读入的缓冲区
            byte[] buffer = new byte[1024];
            int len;
            while ((len = is.read(buffer)) != -1) {
                baos.write(buffer, 0, len);
            }

            // 通知客户端传输结束
            os = socket.getOutputStream();
            os.write("transmission complete.".getBytes(StandardCharsets.UTF_8));

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                baos.close();
                is.close();
                os.close();
                socket.close();
                serverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

执行结果：