Java寫入文本文件無法正常工作

Question

我支持的Java應用程序在平面文件中記錄了一些細節。我有時遇到的問題是，與前一天相比，進入量非常低。此條目最重要，因爲我們的報告是基於文件生成的。我去了寫代碼，我找不出任何問題。正在編寫的方法是同步方法。

有什麼建議嗎？我也可以爲你提供代碼，你可能需要嗎？

public synchronized void log (String connID, String hotline, String callerType, 
     String cli, String lastMenu, String lastInput, 
     String status, String reason) 
    { 
    //String absoluteFP = LOG_LOC + ls + this.getFilename(); 

    //PrintWriter pw = this.getPrintWriter(absoluteFP, true, true); 

    try 
    { 
     pw.print (this.getDateTime()+ ","+connID +","+hotline+","+callerType+","+ cli+"," + lastMenu + "," + lastInput + "," + status + "," + reason);    


     //end 1006 
     pw.print (ls); 
     pw.flush(); 
     //pw.close(); 
    } 
    catch (Exception e) 
    { 
     e.printStackTrace(); 
     return; 
    } 
} 

private synchronized PrintWriter getPrintWriter (String absoluteFileName, 
     boolean append, boolean autoFlush) 
{ 
    try 
    { 
     //set absolute filepath 
     File folder = new File (absoluteFileName).getParentFile();//2009-01-23 

     File f = new File (absoluteFileName); 

     if (!folder.exists())//2009-01-23 
     { 
      //System.out.println ("Call Detailed Record folder NOT FOUND! Creating a new);  
      folder.mkdirs(); 

      //System.out.println ("Configure log folder"); 
      this.setHiddenFile (LOG_LOC);//set tmp directory to hidden folder 

      if (!f.exists()) 
      { 
       //System.out.println ("Creating a new Call Detailed Record...");//2009-01-23 

       f.createNewFile();//2009-01-23 

           } 
     } 
     else 
     { 
      if (!f.exists()) 
      { 
       //System.out.println ("Creating a new Call Detailed Record...");//2009-01-23 

       f.createNewFile();//2009-01-23 


      } 
     } 

     FileOutputStream tempFOS = new FileOutputStream (absoluteFileName, append); 
     if (tempFOS != null) 
     { 
      return new PrintWriter (tempFOS, autoFlush); 
     } 
     else 
     { 
      return null; 
     } 
    } 
    catch (Exception ex) 
    { 
     ex.printStackTrace(); 
     return null; 
    } 
} 

      /** 
      * Set the given absolute file path as a hidden file. 
     * @param absoluteFile String 
     */ 
    private void setHiddenFile (String absoluteFile) 
     { 
    //set hidden file 
    //2009-01-22, KC 
    Runtime rt = Runtime.getRuntime(); 
    absoluteFile = absoluteFile.substring (0, absoluteFile.length() - 1);//2009-01-23 
    try 
    { 
     System.out.println (rt.exec ("attrib +H " + "\"" + absoluteFile +  "\"").getInputStream().toString()); 
    } 
    catch (IOException e) 
    { 
     e.printStackTrace(); 
    } 
} 

private String getDateTime() 
{ 
    //2011-076-09, KC-format up to milliseconds to prevent duplicate PK in CDR table. 
    //return DateUtils.now ("yyyy/MM/dd HH:mm:ss"); 
    return DateUtils.now ("yyyy/MM/dd HH:mm:ss:SSS"); 
    //end 0609 
} 

private String getFilename() 
{ 
    ///return "CDR_" + port + ".dat";//2010-10-01 
    return port + ".dat";//2010-10-01 
} 

public void closePW() 
{ 
    if (pw != null) 
    { 
     pw.close(); 
    } 
} 

Answer 1

你已經創建了一個FileOutputStream，但不關閉該流。關閉該流並重試。這可能會導致問題。

由於垃圾收集器以某些時間間隔開始並關閉FileOutStream，因此有時會收到消息。這然後允許消息被再次記錄。由於在if & else塊中有一個return語句，您將收到無法訪問的錯誤。您必須將PrintWriter和FileOutStreamWriter中的getPrintWriter放在您通常稱爲getPrintWriter()的位置。然後，您將能夠正確關閉流。 getPrintWriter只能保證文件存在，所以其重命名爲ensureFileExistance

Answer 2

如果你可以使用Apache通用IO，試試這個：

public synchronized void log(String connID, String hotline, String callerType, 
     String cli, String lastMenu, String lastInput, 
     String status, String reason) { 
    String absoluteFP = LOG_LOC + ls + this.getFilename(); 
    File file = new File(absoluteFP); 
    String message = this.getDateTime() + "," + connID + "," + hotline + "," + callerType + "," + cli + "," + lastMenu + "," + lastInput + "," + status + "," + reason; 
    try { 
     // note that you must explicitly add new line character if you want the line to end with newline 
     FileUtils.write(file, message + "\n", "UTF-8", true); 
    } catch (IOException ex) { 
     ex.printStackTrace(); 
    } 
} 

在通用IO 2.1，您可以將您書面方式到一個文件中。您現在可以刪除closePW和getPrintwriter，並且由於日誌方法爲​​，可以從同一對象一次寫入一個文件。但是，如果您嘗試同時寫入來自不同對象的同一文件，則最終會覆蓋問題。

另外，Common IO會自動爲您創建丟失的父文件夾。沒有必要明確檢查並創建文件夾。