20day

day20

UDP多线程在线咨询

package com.yan.chat;
​
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
​
public class TalkSend implements Runnable{
    DatagramSocket socket = null;
    BufferedReader reader = null;
​
    private int fromPort;
    private String toIp;
    private int toPort;
​
    public TalkSend( int fromPort, String toIp, int toPort) {
        this.fromPort = fromPort;
        this.toIp = toIp;
        this.toPort = toPort;
​
        try{
            socket = new DatagramSocket(fromPort);
            reader = new BufferedReader(new InputStreamReader(System.in));
        }catch (Exception e){
            e.printStackTrace();
        }
​
    }
​
    @Override
    public void run() {
        try{
            while (true){
                String data = reader.readLine();
                byte[] datas = data.getBytes();
                DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress(this.toIp,this.toPort));
                socket.send(packet);
                if (data.equals("bye")){
                    break;
                }
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        socket.close();
    }
}

package com.yan.chat;
​
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;
​
public class TalkReceive implements Runnable{
    DatagramSocket socket = null;
​
    private int port;
    private String msgFrom;
​
    public TalkReceive(int port,String msgFrom) {
        this.port=port;
        this.msgFrom=msgFrom;
        try {
            socket = new DatagramSocket(port);
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }
​
    @Override
    public void run() {
        while (true){
​
            try {
                //准备接收包裹
                byte[] container = new byte[1024];
                DatagramPacket packet = new DatagramPacket(container,0,container.length,new InetSocketAddress("localhost",8888));
                socket.receive(packet);//阻塞式接收包裹
                //断开连接
                byte[] data = packet.getData();
                String receiveData = new String(data, 0, packet.getLength());
                System.out.println(msgFrom+":"+receiveData);
                if (receiveData.equals("bye")){
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        socket.close();
    }
}

package com.yan.chat;
​
public class TalkStudent {
    public static void main(String[] args) {
        //1.开启两个线程
        new Thread(new TalkSend(7777,"localhost",9999)).start();
        new Thread(new TalkReceive(8888,"老师")).start();
​
    }
}

package com.yan.chat;
​
public class TalkTeacher {
    public static void main(String[] args) {
        new Thread(new TalkSend(5555,"localhost",8888)).start();
        new Thread(new TalkReceive(9999,"学生")).start();
    }
}

URL

统一资源定位符：定位互联网上的某个资源

DNS域名解析： www.baidu.com xxx.xxx.xx.xx将域名解析成IP

---

协议：//IP地址：端口/项目名/资源

package com.yan.lesson04;
​
import java.net.MalformedURLException;
import java.net.URL;
​
public class URLDemo01 {
    public static void main(String[] args) throws Exception {
        URL url = new URL("http://localhost:8080/helloworld/index.jsp?user=wangyan&password=123");
        System.out.println(url.getProtocol());//协议
        System.out.println(url.getHost());//主机IP
        System.out.println(url.getPort());//端口
        System.out.println(url.getPath());//文件地址
        System.out.println(url.getFile());//文件全路径
        System.out.println(url.getQuery());//得到参数
    }
}

在网上下载文件

package com.yan.lesson04;
​
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
​
//http://localhost:8080/wangyan/Security.txt
public class UrlDown {
    public static void main(String[] args) throws Exception {
        //1.下载地址
        URL url = new URL("http://localhost:8080/wangyan/Security.txt");
        //2.连接到这个资源  HTTP
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
​
        InputStream inputStream = urlConnection.getInputStream();
​
        FileOutputStream fos = new FileOutputStream("Security.txt");
​
        byte[] buffer = new byte[1024];
        int len;
        while ((len=inputStream.read(buffer))!=-1){
            fos.write(buffer,0, len);//写出这个数据
        }
        fos.close();
        inputStream.close();
        urlConnection.disconnect();//断开连接
    }
}