Java，Telnet，檢查InputStream中的字符串

Question

我相當原始。我正在嘗試編寫一個Java類來與Telnet進行交互。我看到Apache Commons和Jsacpe擁有API。我正在使用Jscape的Sinetfactory。一旦telnet.connect（）發生，我正在連接的Telnet發送提示以輸入「User name ?:」。我需要驗證這個提示是否真的發生，所以我不只是在有其他事情發生時寫回答。我對此毫無經驗，並確信有一個簡單的答案，只是想知道是否有人能夠提供幫助。

這是我的，它有點馬虎，因爲我一直玩耍一段時間不知道如何實際讀取流中的最後一個字符。

import com.jscape.inet.telnet.*; 

public class TelnetTest extends TelnetAdapter { 

    private final static String USER = "xxx\r"; 
    private final static String PWORD = "yyy\r"; 
    private final static String COMMAND = "zzz\r"; 
    private final static byte[] USER_BYTE = USER.getBytes(); 
    private final static byte[] PWORD_BYTE = PWORD.getBytes(); 
    private final static byte[] COMMAND_BYTE = COMMAND.getBytes(); 
    private Telnet telnet = null; 
    private OutputStream output = null; 
    private static BufferedReader reader = null; 
    private boolean connected = false; 
    private String hostname = "qqq"; 
    //TelnetInputStream tis = null; NOT IN USE AS OF NOW 

    public TelnetTest() throws IOException, TelnetException { 

     // create new Telnet instance 
     telnet = new Telnet(hostname); 

     // register this class as TelnetListener 
     telnet.addTelnetListener(this); 

     // establish Telnet connection 
     telnet.connect(); 
     connected = true; 
     output = telnet.getOutputStream(); 

// HERE IS WHERE I NEED HELP, NOT SURE HOW TO CHECK STREAM 
     String str = null; 
     if ((str = reader.readline()).equals("User name?:")) { 
      telnet.getOutputStream().write(USER_BYTE); 
     } 
// SAME CHECK WOULD HAPPEN HERE FOR "Password" 
     telnet.getOutputStream().write(PWORD_BYTE); 
// ANOTHER SIMILAR CHECK HERE 
     telnet.getOutputStream().write(COMMAND_BYTE); 

     // sends all data entered at console to Telnet server 
     String input = null; 
     while ((input = reader.readLine()) != null) { 
      if (connected) { 
       ((TelnetOutputStream) output).println(input); 
      } else { 
       break; 
      } 
     } 
    } 

    public boolean streamContainsString(Reader reader, String searchString) 
      throws IOException { 
     Scanner streamScanner = new Scanner(reader); 
     if (streamScanner.findWithinHorizon(searchString, 0) != null) { 
      return true; 
     } else { 
      return false; 
     } 
    } 

    // Invoked when Telnet socked is connected. 
    public void connected(TelnetConnectedEvent event) { 
     System.out.println("Connected"); 
    } 

    // Invoked when Telnet socket is disconnected. Disconnect can 
    public void disconnected(TelnetDisconnectedEvent event) { 
     connected = false; 
     System.out.print("Disconnected. Press enter key to quit."); 
    } 

    // Invoked when Telnet server requests that the Telnet client begin performing    specified TelnetOption. 
    public void doOption(DoOptionEvent event) { 
     // refuse any options requested by Telnet server 
     telnet.sendWontOption(event.getOption()); 
    } 

    // Invoked when Telnet server offers to begin performing specified TelnetOption. 
    public void willOption(WillOptionEvent event) { 
     // refuse any options offered by Telnet server 
     telnet.sendDontOption(event.getOption()); 
    } 

    // Invoked when data is received from Telnet server. 
    public void dataReceived(TelnetDataReceivedEvent event) { 
     // print data recevied from Telnet server to console 
     System.out.print(event.getData()); 
    } 

    public Telnet getTelnet() { 
     return telnet; 
    } 

    // starts console program 
    public static void main(String[] args) { 
     try { 
      // create BufferedReader to read data from console 
      reader = new BufferedReader(new InputStreamReader(System.in)); 

      // create new TelnetExample instance 
      TelnetTest example = new TelnetTest(); 

     } catch (Exception e) { 
      e.printStackTrace(System.out); 
     } 
    } 
} 

Answer 1

如果你正在讀/寫字符串，那麼你應該總是使用Reader和Writer。 BufferedReader可以讓你做線路操作。因此，一個BufferedReader纏的Reader（圍繞一個InputStreamReader）將允許你做一個readLine()電話以獲取輸入從連接線：

BufferedReader reader = 
    new BufferedReader(new InputStreamReader(telnet.getInputStream())); 

要寫入連接你可以使用一個Writer圍繞OutputStreamWriter ：

Writer writer = new OutputStreamWriter(telnet.getOutputStream())); 

我不知道這是否與Telnet流工作，但它與原始Socket工作。然後，您可以做類似下面的僞代碼：

while (true) { 
    read a line from the server 
    some sort of if/then/else to test for the output 
    write your username/password or whatever is appropriate for the connection 
    repeat until some logout or IOException... 
} 

阿帕奇Telnet類有很多有趣的監聽器和其他處理這些，如果你想，但學習曲線可能會更你可以使用的。下面是使用TelnetClient一個很好的示例應用程序：「驗證此提示是實際發生」

http://www.java2s.com/Code/Java/Network-Protocol/ExampleofuseofTelnetClient.htm