multithreading与客户端服务器程序

我正在尝试使用我一直在研究的客户端/服务器程序实现multithreading。 我需要允许多个客户端同时连接到服务器。 我目前有4个类：客户端，服务器，协议和处理线程的工作者。 以下代码是我对这些类的代码：

SocketServer类：

public class SocketServer { public static void main(String[] args) throws IOException { int portNumber = 9987; try ( ServerSocket serverSocket = new ServerSocket(portNumber); Socket clientSocket = serverSocket.accept(); PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true); BufferedReader in = new BufferedReader( new InputStreamReader(clientSocket.getInputStream())); ) { Thread thread = new Thread(new ClientWorker(clientSocket)); thread.start(); //start thread String inputLine, outputLine; // Initiate conversation with client Protocol prot = new Protocol(); outputLine = prot.processInput(null); out.println(outputLine); while ((inputLine = in.readLine()) != null) { outputLine = prot.processInput(inputLine); out.println(outputLine); if (outputLine.equals("quit")) break; } } catch (IOException e) { System.out.println("Exception caught when trying to listen on port " + portNumber + " or listening for a connection"); System.out.println(e.getMessage()); } } } 

SocketClient类：

 public class SocketClient { public static void main(String[] args) throws IOException { String hostName = "localhost"; int portNumber = 9987; try ( Socket socket = new Socket(hostName, portNumber); PrintWriter out = new PrintWriter(socket.getOutputStream(), true); BufferedReader in = new BufferedReader( new InputStreamReader(socket.getInputStream())); ) { BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in)); String fromServer; String fromUser; while ((fromServer = in.readLine()) != null) { System.out.println("Server: " + fromServer); if (fromServer.equals("quit")) break; fromUser = stdIn.readLine(); if (fromUser != null) { System.out.println("Client: " + fromUser); out.println(fromUser); } } } catch (UnknownHostException e) { System.err.println("Don't know about host " + hostName); System.exit(1); } catch (IOException e) { System.err.println("Couldn't get I/O for the connection to " + hostName); System.exit(1); } } } 

协议类：

 public class Protocol { private static final int waiting = 0; private static final int sentPrompt = 1; private int status = waiting; public String processInput(String theInput) { String theOutput = null; if (status == waiting) { theOutput = "Please enter what you would like to retrieve: 'customer' or 'product' "; status = sentPrompt; } else if ( status == sentPrompt ) { if ( theInput.equalsIgnoreCase("product")) { File f = new File("product.txt"); Scanner sc = null; try { sc = new Scanner(f); } catch (FileNotFoundException ex) { Logger.getLogger(Protocol.class.getName()).log(Level.SEVERE, null, ex); } while ( sc.hasNextLine() ) { String line = sc.nextLine(); theOutput = "The current product entries are : " + line; } return theOutput; } else if ( theInput.equalsIgnoreCase("customer")) { File f = new File("customer.txt"); Scanner sc = null; try { sc = new Scanner(f); } catch (FileNotFoundException ex) { Logger.getLogger(Protocol.class.getName()).log(Level.SEVERE, null, ex); } while ( sc.hasNextLine() ) { String line = sc.nextLine(); theOutput = "The current customer entries are : " + line; } return theOutput; } else if ( theInput.equalsIgnoreCase("quit")) { return "quit"; } else { return "quit"; } } return theOutput; } } 

ClientWorker类：

 public class ClientWorker implements Runnable { private final Socket client; public ClientWorker( Socket client ) { this.client = client; } @Override public void run() { String line; BufferedReader in = null; PrintWriter out = null; try { System.out.println("Thread started with name:"+Thread.currentThread().getName()); in = new BufferedReader(new InputStreamReader(client.getInputStream())); out = new PrintWriter(client.getOutputStream(), true); } catch (IOException e) { System.out.println("in or out failed"); System.exit(-1); } while (true) { try { System.out.println("Thread running with name:"+Thread.currentThread().getName()); line = in.readLine(); //Send data back to client out.println(line); //Append data to text area } catch (IOException e) { System.out.println("Read failed"); System.exit(-1); } } } } 

当我运行服务器和客户端时，一切都按预期正常工作。 然后，当我尝试运行另一个客户端时，它只是挂起并且不会提示客户端给出响应。 我非常感谢您对我所缺少的任何见解！

Answer 1

您的服务器代码应该解决以下function。

1. 继续在while循环中接受来自ServerSocket的套接字

2. 通过传递客户端套接字即Socket，在accept（）调用之后创建新线程

3. 在客户端套接字线程中进行IO处理，例如ClientWorker 。

看看这篇文章

你的代码应该是

 ServerSocket serverSocket = new ServerSocket(portNumber); while(true){ try{ Socket clientSocket = serverSocket.accept(); Thread thread = new ClientWorker(clientSocket); thread.start(); //start thread }catch(Exception err){ err.printStackTrace(); } } 

Answer 2

serverSocket.accept()被调用多少次？ 一旦。 这就是它将处理多少客户端。 试图联系的后续客户将不会有任何人收听它们。

要处理更多客户端，需要在循环中调用serverSocket.accept() 。