利用java的socket发送一个类

秒速五厘米 2022-06-09 04:54 188阅读 0赞

**注意注意注意！需要串行化！**

用socket可以简单的发送一些文本信息，太复杂的可能发送不了，比如图片音频可能要用到http来发送和接收了。最基本的使用socket来发送一个字符串，但有的时候我们希望能够发送一个类，这样server接收端处理信息将会非常方便。

对于待发送的类，要用socket来发送，则必须实现Serializable接口。实现这个接口后就将发送的对象串行化了，再使用对象输入输出流（ObjectOutputStream, ObjectInputStream）就可实现发送与接收。这个过程有点像通信里边的调制过程，在接收端server再将串行化的对象恢复成之前的类，就像解调过程。比如我们定义一个packets这个类，来发送一些信息。

![复制代码][copycode.gif]

import java.io.Serializable;
    
    public class Packets implements Serializable{
        
        public int id;
        public String value;
        public int ballot_pid;
        public int ballot_num;
        public int position;
        
        public Packets(int id, String value, int ballot_pid, int ballot_num, int position){
            this.id= id;
            this.value= value;
            this.ballot_pid= ballot_pid;
            this.ballot_num= ballot_num;
            this.position= position;
    
        }    
    }

![复制代码][copycode.gif]

在发送的时候，我们定义一个client类。每次我们想发送packets，都先用packets的构造函数新建一个包，比如Packets pack= new Packets(......); 然后再用client里的send方法来将包发送出去，即client.send(pack)就可。

![复制代码][copycode.gif]

import java.io.IOException;
    import java.io.ObjectOutputStream;
    import java.net.Socket;
    import java.net.UnknownHostException;
    
    public class Client{
        private int port= 2013;
        private String host= "127.0.0.1";
        
        public Client(String host, int port){
            this.host= host;
            this.port= port;
        }
        
        public void send(Packets packets) throws UnknownHostException, IOException{
            Socket socket= new Socket(host, port);
            
            ObjectOutputStream os= new ObjectOutputStream(socket.getOutputStream());
            os.writeObject(packets);
            socket.getOutputStream().flush();
            socket.close();
        }
    }

![复制代码][copycode.gif]

在接收的时候，用ObjectInputStream来获取这个包。

![复制代码][copycode.gif]

import java.io.IOException;
    import java.io.ObjectInputStream;
    import java.net.ServerSocket;
    import java.net.Socket;
    
    public class Server extends Thread{
        private int port= 2013;
        private int sequence= 1;
        
        /*flag used to stop this thread*/
        private boolean stop= false;
        
        
        /*pass addresses of clients from outside*/
        public Server(int port){
            this.port= port;
        }
        
        public void run(){
            Socket socket= null;
            try{
                ServerSocket serverSocket= new ServerSocket(port);
                while(!stop){
                    socket= serverSocket.accept();
                    handleSocket(socket);
                }
            }
            catch(Exception e){
                e.printStackTrace();
            }
            
            super.run();
        }
        
        private void handleSocket(Socket socket) throws IOException, ClassNotFoundException{
            ObjectInputStream ois= new ObjectInputStream(socket.getInputStream());
            Packets packets= (Packets)ois.readObject();
            
            /*handle packets start*/
            /*if broadcast, use 'Blog.broadcast(Packets packets)'*/
            System.out.println("id : "+ packets.id);
            System.out.println("val: "+ packets.value);
            System.out.println("pid: "+ packets.ballot_pid);
            System.out.println("num: "+ packets.ballot_num);
            System.out.println("pos: "+ packets.position);    
            /*handle packets end*/
            
            socket.close();
        }
        
        /*function used to fail this server*/
        public void fail(){
            this.stop= true;
        }
        
        /*function used to restart this server*/
        public void unfail(){
            this.stop= false;
        }    
        
    }

![复制代码][copycode.gif]

[copycode.gif]: /images/20220609/ccf3207b15664be09055c5cd41e15eaa.png