創建一個基於命令的記錄程序

Question

我目前正在嘗試製作一個創建和寫入日誌文件的java程序。

它有2個類（一個用於請求，一個用於工作者代碼）。一個班級有一個文本字段並允許您輸入命令。命令應該像'log start'或'log stop'一樣。

所以請求類發送命令作爲一個字符串，工人階級獲取命令，對其進行解析並執行指令（開始記錄，停止記錄

我的問題是：當用戶進入應用程序不會停止記錄'停止'命令，並且它在3個日誌條目之後不會停止（這是問題，我想在用戶輸入命令時停止它），當你看看代碼時，你會更好地理解問題

我知道我在這裏犯了一個非常基本的錯誤，但不知何故目前無法弄清楚，並希望您對這個問題的看法（我在代碼中顯示有問題）謝謝

錯誤：

Exception in thread "stoplogging" java.lang.ArrayIndexOutOfBoundsException: 1 
    at Response$ClientProcess$1StopperThread.run(Response.java:109) 
    at java.lang.Thread.run(Unknown Source) 

Request類：

public class Request extends JFrame { 
private JTextArea consoleArea = new JTextArea(); 
private JTextField cmd_prompt = new JTextField(); 
private JLabel cmd_label = new JLabel("Enter command: "); 

// ********IP PORT TEXTFIELDS & CONNECT BUTTON******* !!!! 

private DataOutputStream output; 
private DataInputStream input; 


public static void main(String[] args) { 
    new Request(); 
} 

Socket socket = null; 
String command; 
public Request(){ 
    JPanel requestPanel = new JPanel(); 
    requestPanel.setLayout(new BorderLayout()); 
    setTitle("Project_3002_CLIENT"); 
    requestPanel.add(cmd_label, BorderLayout.WEST); 
    requestPanel.add(cmd_prompt, BorderLayout.CENTER); 
    setLayout(new BorderLayout()); 
    add(requestPanel, BorderLayout.NORTH); 


    add(new JScrollPane(consoleArea), BorderLayout.CENTER); 
    Font font = new Font("Courier New", Font.BOLD, 15); 
    cmd_prompt.setFont(font); 
    cmd_prompt.setAlignmentX(LEFT_ALIGNMENT); 
    cmd_prompt.addActionListener(new TextFieldListener()); 
    setSize(600, 270); 
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    consoleArea.setFont(font); 
    setVisible(true); 

    String ip = "127.0.0.1"; // THIS WILL BE CHANGED (make custom) --extra jframe 
    int port = 4588; // THIS WILL BE CHANGED (make custom) -- extra jframe 
    try { 
     socket = new Socket(ip, port); 
     //IO connection stuff 
     input = new DataInputStream(socket.getInputStream()); 
     output = new DataOutputStream(socket.getOutputStream()); 
    } 
    catch (IOException ex) { 
     consoleArea.append("Connection refused. Please check if the server is running.\n"); 
    } 

} 

class SenderThirty implements Runnable{ 

    Thread send30secs; 
    public SenderThirty(){ 
    } 

    public SenderThirty(String send30s){ 
     send30secs = new Thread(this, send30s); 
     send30secs.start(); 
    } 

    @Override 
    public void run() { 
     try { 
      output.writeUTF(command); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 

} 

private class TextFieldListener implements ActionListener{ 
    public void actionPerformed(ActionEvent e) { 
     try { 
      command = cmd_prompt.getText(); 

      if (command.contains("start") == true){ 

       Thread sendstart = new Thread(new SenderThirty(), "send"); 
       sendstart.start(); 
       //continue 
      } 

      else if (command.contains("stop") == true){ 
       Thread sendstop = new Thread(new SenderThirty(), "send"); 
       sendstop.start(); 
       //continue 
      } 

      else {consoleArea.append("\nInvalid command\n");} 


     } catch (Exception e1) { 
      consoleArea.append("\nERR!\n"); 
     } 
    } 
}} 

Worker類：​​

public class Response { 
String path = ""; 

public static void main(String[] args) throws InterruptedException { 
    new Response(); 
} 

ServerSocket resp_sock; 
public Response() throws InterruptedException { 

    int port = 4588; 
    try { 
     resp_sock = new ServerSocket(port); 

     int clientNo = 1; 

     while (true) { 
      Socket socket = resp_sock.accept(); 


      // client's IP address 
      InetAddress client_addr = socket.getInetAddress(); 

      ClientProcess task = new ClientProcess(socket); 
      new Thread(task).start(); 

      clientNo++; 
     } 

    } catch (IOException ex) { 
     JOptionPane.showMessageDialog(null, ex); 
    } 

} 

class ClientProcess implements Runnable { 

    private Socket socket; 

    public ClientProcess(Socket socket) { 
     this.socket = socket; 
    } 

    @Override 
    public void run() { 

     try { 
      final DataInputStream input = new DataInputStream(socket.getInputStream());//from client 
      //DataOutputStream output = new DataOutputStream(socket.getOutputStream());//to client 

      while(true){ 
       String prompt = input.readUTF(); 
       String command[] = prompt.split(" "); 
       final Logger logger = Logger.getLogger("MyLog"); 
       FileHandler fh;    
       fh = new FileHandler("C:\\..path..\\logfile.log"); 
       logger.addHandler(fh);      
       SimpleFormatter formatter = new SimpleFormatter(); 
       fh.setFormatter(formatter); 




       class StopperThread implements Runnable{ 
        public StopperThread(){ 
        }   
        @Override 
        public void run() { 
         try { ////////////////////////////////////////***PROBLEM IS IN THIS TRY BLOCK*** 
          String next_prompt; 
          next_prompt = input.readUTF(); 
          String nextCommand[] = next_prompt.split(" "); 

          if(nextCommand[1].equalsIgnoreCase("stop")){ 
           logger.info("STOPPED " + new Date() + " \n"); 
           System.exit(0);} 

         } catch (IOException e) { 
          e.printStackTrace(); 
         } 

       }} 






       if(command[1].equalsIgnoreCase("start")){ 
        try { 

         while(true){ 
          logger.info("RUNNING " + new Date() + " \n"); 
          Thread.sleep(5000); 

          Thread stoplogging = new Thread(new StopperThread(), "stoplogging"); 
          stoplogging.start(); 

         } 

        } catch (SecurityException e) { 
         e.printStackTrace(); 
        } catch (InterruptedException e) { 
         e.printStackTrace(); 
        } 
       } 


       if(command[1].equalsIgnoreCase("stop")){ 
        logger.info("STOPPED " + new Date() + " \n"); 
       } 


      } 
     } catch (IOException ex) { 
      JOptionPane.showMessageDialog(null, ex); 
     } 
    } 

}} 

Answer 1

if(nextCommand[1].equals...)是最有可能的罪魁禍首。

如果沒有空格（」「）拆分的字符串，在這種情況下nextCommand的長度將是1，2，不

你應該事先檢查長度，則會引發NPE。注意：與command[1]相同的潛在錯誤。