网络编程

UDP协议

不管接收端是否存在都会执行发生操作,并且接收端不会做出响应,`

public class Demo {
    public static void main(String[] args) throws IOException {
        //DatagramSocket封装了upd协议的相关方法
        DatagramSocket ds = new DatagramSocket();
        String s = "hello";
        InetAddress ip = InetAddress.getByName("127.0.0.1");
        //字节数组,长度,长度,ip,端口号
        System.out.println(ip);
        DatagramPacket dp= new DatagramPacket(s.getBytes(),0,s.getBytes().length,ip,8888);
        ds.send(dp);//发送要发的数据
        ds.close();

    }
}

public class Receive {
    public static void main(String[] args) throws IOException {
        //服务器没有指定ip默认本地主机,要指定端口号
        DatagramSocket ds = new DatagramSocket(8888);
          byte[] bytes = new byte[1024];//通过字节数组接受客户端的数据
          DatagramPacket dp = new DatagramPacket(bytes,0,bytes.length);
          ds.receive(dp);
        //  String s = new String(bytes,0,bytes.length);
          String s2 = new String(bytes,0,bytes.length);
          System.out.println(s2);
          ds.close();
    }
}

客户端从键盘输入数据服务端接受输出控制台

//客户端
public class SendDemo {
    public static void main(String[] args)throws Exception{
        DatagramSocket ds = new DatagramSocket();
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line;
        InetAddress ip = InetAddress.getByName("127.0.0.1");
        while ((line=br.readLine())!=null){
            DatagramPacket p = new DatagramPacket(line.getBytes(),0,line.getBytes().length,ip,8888);
            ds.send(p);
            if (line.equals("haha")){
                break;
            }
        }
    }
}

//接收端
public class ReceiveDemo {
    public static void main(String[] args)throws Exception{
        DatagramSocket ds = new DatagramSocket(8888);
        while (true){
            byte[] bytes = new byte[1024];
            DatagramPacket p = new DatagramPacket(bytes,0,bytes.length);
            ds.receive(p);
            System.out.println(new String(bytes,0,bytes.length));
        }
    }
}

TCP

会对客户端发生的数据做出回应

public class Send {
    public static void main(String[] args)throws Exception{
        //Socket类封装了TCP协议的相关方法,代表TCP客户端
        Socket s = new Socket("127.0.0.1",8888);
        //获取字节输出流
        OutputStream os = s.getOutputStream();
        os.write("你好TCP".getBytes());
        os.close();
        s.close();
    }
}

  public static void main(String[] args)throws Exception{
        ServerSocket ss = new ServerSocket(8888);
        //accept方法表示接受客户端的连接
        Socket accept = ss.accept();
        InputStream is = accept.getInputStream();
        byte[] bytes = new byte[1024];
        int read = is.read(bytes);
        System.out.println(new String(bytes,0, read));
    }
}

TCP客户端接收服务器返回的数据

public class Send {
    public static void main(String[] args)throws Exception{
        Socket s = new Socket("127.0.0.1", 6666);
        //获取字节输出流,向服务端写数据
        OutputStream os = s.getOutputStream();
        //开始写数据
        os.write("我想服务器端写数据".getBytes());
        //接受服务器返回的数据,获取输入流读取数据
        InputStream is = s.getInputStream();
        byte[] bytes = new byte[1024];
        int read = is.read(bytes);
        System.out.println(new String(bytes,0,read));
        is.close();
        os.close();
        s.close();
    }
}


public class Receive {
    public static void main(String[] args)throws Exception{
        ServerSocket ss = new ServerSocket(6666);
        Socket accept = ss.accept();
        //获取字节输入流读取客户端的数据
        InputStream is = accept.getInputStream();
        byte[] bytes = new byte[1024];
        int read = is.read(bytes);
        System.out.println(new String(bytes,0,read));

        //写数据返回给客户端做出回应
        //获取字节输出流向客户端写数据
        OutputStream os = accept.getOutputStream();
        os.write("你好我收到你的数据了".getBytes());
        accept.close();
        ss.close();
    }
}

TCP客户端键盘录入数据发送到服务器写入文件

public class Send {
    public static void main(String[] args)throws Exception{
        Socket s = new Socket("127.0.0.1", 1111);
        OutputStream os = s.getOutputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line;
        while ((line=br.readLine())!=null){
            os.write(line.getBytes());
        }

    }
}


public class Receive {
    public static void main(String[] args)throws Exception{
        ServerSocket ss = new ServerSocket(1111);
        Socket accept = ss.accept();
        InputStream is = accept.getInputStream();
        int len;
        byte[] bytes = new byte[1024];
        FileOutputStream fos = new FileOutputStream("D:\\Idea-workplace\\寒假复习\\网络编程\\d.txt");
        while ((len=is.read(bytes))!=-1){
            if (new String(bytes,0,len).equals("haha")){
                break;
            }
            fos.write(bytes,0,len);
            fos.flush();
        }

    }
}

TCP客户端读取本地文件服务器保存在文件夹中

public class Send {
    public static void main(String[] args)throws Exception{
        Socket s = new Socket("127.0.0.1", 1111);
        OutputStream os = s.getOutputStream();
        FileInputStream is = new FileInputStream("D:\\Idea-workplace\\寒假复习\\网络编程\\静夜思.txt");
        int len;
        byte[] bytes =new byte[1024];
        while ((len=is.read(bytes))!=-1){
            os.write(bytes,0,len);
        }
        //告诉服务器数据发送完毕
        s.shutdownOutput();
        InputStream is1 = s.getInputStream();
        byte[] bytes1 = new byte[1024];
        int read = is1.read(bytes1);
        System.out.println(new String(bytes1,0,read));
    }
}


public class Receive {
    public static void main(String[] args)throws Exception{
        ServerSocket ss = new ServerSocket(1111);
        Socket accept = ss.accept();
        InputStream is = accept.getInputStream();
        int len;
        byte[] bytes = new byte[1024];
        OutputStream os = new FileOutputStream("D:\\Idea-workplace\\寒假复习\\网络编程\\jys.txt");
        while ((len=is.read(bytes))!=-1){
            os.write(bytes,0,len);
            os.write("\r\n".getBytes());
            os.flush();
        }
        System.out.println("-----------------------------");
        //做出回应
        OutputStream os1 = accept.getOutputStream();
        os1.write("好的我收到你的数据了".getBytes());
    }
}
//\r\n是换行符号

来源：CSDN

作者：無觞

链接：https://blog.csdn.net/qq_45123018/article/details/104076645