java网络编程-实现聊天程序

女爷i 2022-09-11 06:09 275阅读 0赞

利用Datagramsocket创建连接，实现UDP，并使用多线程实现教师端和学生端的聊天。  
接收端的程序如下：

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by FernFlower decompiler)
    //
    
    package chats;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    
    public class talkreceive implements Runnable {
        
        DatagramSocket socket = null;//初始化一个socket连接
        private int port;//端口号
        private String msgfrom;//消息来源
    
        public talkreceive(int port, String msgfrom) {
        //构造函数
            this.port = port;
            this.msgfrom = msgfrom;
    
            try {
        
                this.socket = new DatagramSocket(this.port);
            } catch (Exception var4) {
        
                var4.printStackTrace();
            }
    
        }
    
        public void run() {
        
            while(true) {
        
                try {
        
                    byte[] container = new byte[1024];//开创一个字节数组作为缓冲区
                    DatagramPacket packet = new DatagramPacket(container, 0, container.length);//创建一格数据包
                    this.socket.receive(packet);//通过传入的socket连接，接受数据包。
                    byte[] bytes1 = packet.getData();//读取包中数据
                    String ans = new String(bytes1, 0, bytes1.length);
                    System.out.println(this.msgfrom + ":" + ans);
                    if (!ans.trim().equals("bye")) {
        
                        continue;
                    }//接受到bye则结束聊天。
    
                    this.socket.close();
                } catch (Exception var5) {
        
                    var5.printStackTrace();
                }
    
                return;
            }
        }
    }

数据发送端的写法：

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by FernFlower decompiler)
    //
    
    package chats;
    
    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 bufferedReader = null;
        private int fromport;
        private String toip;
        private int toport;
    
        public talksend(int fromport, String toip, int toport) {
        //成员包括发送端口，目标ip，目标端口
            this.fromport = fromport;
            this.toport = toport;
            this.toip = toip;
    
            try {
        
                this.socket = new DatagramSocket(fromport);
                this.bufferedReader = new BufferedReader(new InputStreamReader(System.in));//使用bufferreader读取系统流的输入。
            } catch (Exception var5) {
        
                var5.printStackTrace();
            }
    
        }
    
        public void run() {
        
            while(true) {
        
                try {
        
                    String data = this.bufferedReader.readLine();//流中的一行字符
                    byte[] Data = data.getBytes();
                    DatagramPacket packet = new DatagramPacket(Data, 0, Data.length, new InetSocketAddress(this.toip, this.toport));//InetSocketAddress类创建一个目标地址，并将得到的socket作为数据包的发送链接
                    this.socket.send(packet);
                    String ques = new String(Data, 0, Data.length);
                    if (!ques.trim().equals("bye")) {
        
                        continue;
                    }//加trim去掉空格。
    
                    this.socket.close();
                } catch (Exception var5) {
        
                    var5.printStackTrace();
                }
    
                return;
            }
        }
    }

学生类和教师类，创建两个线程，分别为发送和接受。

package chats;
    
    public class talkstudent {
        
        public talkstudent() {
        
        }
    
        public static void main(String[] args) {
        
            (new Thread(new talksend(7777, "localhost", 9999))).start();//向9999端口发送
            (new Thread(new talkreceive(8888, "老师"))).start();//在8888端口接收
        }
    }

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by FernFlower decompiler)
    //
    
    package chats;
    
    public class talkteacher {
        
        public talkteacher() {
        
        }
    
        public static void main(String[] args) {
        
            (new Thread(new talksend(5555, "localhost", 8888))).start();//向8888端口发送
            (new Thread(new talkreceive(9999, "学生"))).start();//在9999端口接受.
        }
    }

附：  
java通过URL类，下载网络资源。  
首先可以通过网络抓包的方式，获取目标视频或音乐的url的值。  
先创建一个URL对象，之后通过openconnection方法创建连接，由于大多数网站使用https协议，将其进行强制类型转换为HttpURLConnection，万物皆为流，使用inputStream读取http连接，在使用FileOutputStream将内容下载到指定的文件位置。

package URLtest;
    
    import java.io.FileOutputStream;
    import java.io.InputStream;
    import java.net.HttpURLConnection;
    import java.net.URL;
    
    public class URLtest {
        
        public static void main(String[] args) throws Exception{
        
            URL url=new URL("https://m701.music.126.net/20210908204202/62ad2629c5959aa955d40bbe360fb3fd/jdyyaac/obj/w5rDlsOJwrLDjj7CmsOj/10534066865/ec0a/9bbc/3590/b4d04ce9553a85b39d002fbdfa1938e1.m4a");
            HttpURLConnection httpURLConnection=(HttpURLConnection) url.openConnection();//强转
            InputStream inputStream=httpURLConnection.getInputStream();
            FileOutputStream fos=new FileOutputStream("b4d04ce9553a85b39d002fbdfa1938e1.m4a");
            byte[] bytes=new byte[1024];
            int len;
            while((len=inputStream.read(bytes))!=-1){
        
                fos.write(bytes,0,bytes.length);
            }
            fos.close();
            inputStream.close();
            httpURLConnection.disconnect();
        }
    }