简单使用TCP协议,实现客户端和服务器端之间的文件和信息传输,并实现可以重复添加自定义文件的类型和名称.
 

//服务器端:

public static void main(String[] args) throws IOException {
    ServerSocket ss = new ServerSocket(9990);

    while (true) {
        Socket socket = ss.accept();
        读,输入流
        InputStream in = socket.getInputStream();
        //写,输出
        OutputStream out = socket.getOutputStream();
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(out));
        BufferedReader bf = new BufferedReader(new InputStreamReader(in));
        //读取文件的名字.
        String s = bf.readLine();
        System.out.println(s);//a.mp4;
        //给客户端一个反馈,告诉客户端自己已经看到文件名字了
        bw.write("我已经看到文件名字了,可以上传文件了");
        bw.newLine();
        bw.flush();
        String s1 = UUID.randomUUID().toString();

        FileOutputStream fos = new FileOutputStream("Day16Class/"+s1+s);
        byte[] arr = new byte[1014 * 8];
        int len;
        //使用in去读;fos来写

        while ((len =in.read(arr))!=-1){
            fos.write(arr,0,len);
        }
        bw.write("上传成功");
        bw.newLine();
        bw.flush();
    }
}
============================================

//客户端
public static void main(String[] args) throws IOException {
    Socket s = new Socket("127.0.0.1", 9990);
    InputStream in = s.getInputStream();
    OutputStream out = s.getOutputStream();
    BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(out));
    BufferedReader bf = new BufferedReader(new InputStreamReader(in));
    //第一步:获取文件名字
    File file = new File("d:/dpcq.txt");
    //获取文件名字
    String name = file.getName();
    //使用字符缓冲流写
    bw.write(name);
    bw.newLine();
    bw.flush();
    //第二步:
    //得到服务器的反馈
    String s1 = bf.readLine();
    System.out.println(s1);//我已经看到文件名字了,可以上传文件了

    //第三补:开始读取文件
    FileInputStream fil = new FileInputStream(file);
    byte[] arr = new byte[1024 * 8];
    int len;
    //写
    while ((len = fil.read(arr)) != -1) {
        out.write(arr, 0, len);
    }
    //告诉服务器我已经读完了,不再读了
    s.shutdownOutput();
    String s2 = bf.readLine();
    System.out.println(s2);

}