JAVA上机任务十二（网络编程）

import java.net.InetAddress;
public class shangji1201 {
    public static void main(String[] args) throws Exception{
        InetAddress localAddress = InetAddress.getLocalHost();
        InetAddress remoteAddress = InetAddress.getByName("www.oracle.com");
        System.out.println("本机的IP地址：" + localAddress.getHostAddress());
        System.out.println("本机的主机名：" + localAddress.getHostName());
        System.out.println("甲骨文公司主机的IP地址：" + remoteAddress.getHostAddress());
    }

}

发送端：

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;


public class shangji1201send {
    public static void main(String[] args) throws Exception{
        DatagramSocket ds=new DatagramSocket(3000);
        String str="Hello World";
        byte[] buf=new byte[1024];
        DatagramPacket dp=new DatagramPacket(str.getBytes(), str.length(),InetAddress.getByName("localhost"),8001);
        DatagramPacket dp2=new DatagramPacket(buf, 1024);
        System.out.println("发送信息");
        ds.send(dp);

        System.out.println("发送成功!");
        System.out.println("等待回应!");
        ds.receive(dp2);
        System.out.println("收到来自" + dp2.getAddress().getHostAddress()+":"+dp2.getPort() + "的回应:");
        String str2=new String(dp2.getData(), 0, dp2.getLength());
        System.out.println(str2);

        ds.close();
    }
}

 接收端：

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class shangji1202receive {
        public static void main(String[] args) throws IOException
        {
            String str2="OK!";
            DatagramPacket dp2=new DatagramPacket(str2.getBytes(), str2.length(), InetAddress.getByName("localhost"),3000);
            byte[] buf=new byte[1024];
            DatagramSocket ds=new DatagramSocket(8001);
            DatagramPacket dp=new DatagramPacket(buf, 1024);
            System.out.println("等待接受数据中:");
            System.out.println("接收到来自");
            ds.receive(dp);
            System.out.println(dp.getAddress().getHostAddress()+":"+dp.getPort() + "的数据:");
            String str=new String(dp.getData(), 0, dp.getLength());
            System.out.println(str);

            System.out.println("接收成功!");
            ds.send(dp2);
            ds.close();
        }

}