模拟客户端和服务端

import org.junit.jupiter.api.Test;

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

/**
 * 服务端和客户端在本例中都有本机（127.0.0.1）充当
 */
public class TcpTest {
    /**
     * 模拟客户端：
     * 发送本地图片到服务器，并接受服务器发过来的确认消息，打印在控制台
     * 可循环上传
     * 多线程处理客服端的上传请求
     */
    @Test
    public void client() {
        Socket socket=null;
        FileInputStream fi=null;
        try {
            InetAddress inetAddress=InetAddress.getLocalHost();
            socket=new Socket(inetAddress,8888);
            OutputStream so = socket.getOutputStream();

            fi=new FileInputStream(new File("src/xn/socketTest/1.jpg"));
            byte[] bytes=new byte[1024];
            int len;
            while ((len=fi.read(bytes))!=-1){
                so.write(bytes,0,len);
            }
            socket.shutdownOutput();

            InputStream si = socket.getInputStream();
            byte[] bytes1=new byte[20];
            int len1;
            while ((len1=si.read(bytes1))!=-1){
                System.out.println(new String(bytes1,0,len1));
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if(fi!=null){
                try {
                    fi.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(socket!=null){
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }




    }

    /**
     * 模拟服务器，接受来自客服端上传的图片，并保存在服务器的本地文件夹中
     */
    @Test
    public void server() throws IOException {
        ServerSocket serverSocket = new ServerSocket(8888);
        while (true){
            Socket socket = serverSocket.accept();
            new Thread(new Runnable() {
                @Override
                public void run() {
                    FileOutputStream fo=null;
                    try {
                        InputStream si = socket.getInputStream();
                        String filename=""+System.currentTimeMillis()+(Math.random()*99999+1);

                        fo=new FileOutputStream(new File("src/xn/xnjt/"+filename+".jpg"));

                        byte[] bytes=new byte[1024];
                        int len=0;
                        while ((len=si.read(bytes))!=-1){
                            fo.write(bytes,0,len);
                        }

                        OutputStream so = socket.getOutputStream();
                        so.write("照片已收到,嘻嘻!!".getBytes());
                    }catch (Exception e){
                        e.printStackTrace();
                    }finally {
                        if(fo!=null){
                            try {
                                fo.close();
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                        }
                        if(socket!=null){
                            try {
                                socket.close();
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                        }
                    }

                }
            }).start();



        }
    }

}