while 循环只打印一次而不是整个循环

Question

我有一个程序，我在其中使用 while 循环来打印到控制台和 html 文件。然而，即使它打印到控制台，程序也只会将最后一行打印到 html 文件。这是我的循环的代码，它应该打印从文本文件中提取的第 9 到 16 行的信息。

  //read the txt file
Path objPath = Paths.get("dirsize.txt");  
if (Files.exists(objPath))
{

    File objFile = objPath.toFile();
  try(BufferedReader in = new BufferedReader(
                          new FileReader(objFile)))
   {
    String line = in.readLine();
    int lineNum = 1;
    //extract the month
    String monthSubstring = line.substring(25,27);
    month = Integer.parseInt(monthSubstring) -1 ;
    //extact the year
    String yearSubstring = line.substring(31,35);
    year = (Integer.parseInt(yearSubstring));
    //extract the date
    String daySubstring = line.substring(28,30);
    day = Integer.parseInt(daySubstring);
     PrintWriter out = new PrintWriter (new BufferedWriter(new FileWriter("Output.html")));
    while(line != null)
    {
      line = in.readLine();
      lineNum ++;
      if (lineNum == 3)
       {
           //extract the hour
            String hourSubstring = line.substring(21,23);
             hour = Integer.parseInt(hourSubstring); 
            //extract the minute
            String minuteSubstring = line.substring(24,26);
             minute = Integer.parseInt(minuteSubstring);
            //extract the second
            String secondSubstring = line.substring(27,29);
            second= Integer.parseInt(secondSubstring);
           }
      if(lineNum ==5)
       {
            //Extract the branch
            strBranch = line.substring(22, 27);        
       }        
      if (lineNum == 6)
      {
             //Extract the computer
             strCPU = line.substring(26,32);
      }   
     if (lineNum >= 9 && lineNum <= 16)
      {
          //call the MyDirectory methods to get the files name,size and number of files
          MyDirectory directory = new MyDirectory(line);
          fileName = directory.getName();
          fileSize = directory.getsize();
          fileNum = directory.getNum();
          //create the dteDate calender
          GregorianCalendar dteDate = new GregorianCalendar(year, month, day, hour, minute, second);
          //fromat the date
          SimpleDateFormat strDate = new SimpleDateFormat("MMM dd, yyyy h:m");
        //Write the data to the file
         out.println((strBranch + "; " +
                  strCPU + "; "  + 
                  strDate.format(dteDate.getTime())) + "; " +
                  fileName + "; " +
                  fileSize + "; " + 
                  fileNum);
         //create the necessary output for the console
          System.out.println((strBranch + "; " +
                  strCPU + "; "  + 
                  strDate.format(dteDate.getTime())) + "; " +
                  fileName + "; " +
                  fileSize + "; " + 
                  fileNum);
        }    
       out.flush();
    }

   }   

  //catch any IOExceptions and print out e
 catch (IOException e)
  {
    System.out.println(e);  
  }

}

编辑：通过答案中发布的建议，我现在有了所有内容的输出，但我很难对其进行格式化，html 文件包含所有行，没有空格我尝试在输出末尾使用“\n”但是那么我的代码无法编译，因为它说不允许 null 有谁知道如何将其格式化为行，因为它不允许我在打印方法的末尾放置“\n”？

我不确定这是代码太多还是不足以解决问题，如果我应该在帖子中添加任何内容或删除任何内容，请告诉我。

Answer 1

这很明显 - 每次 while 循环迭代时都会创建文件（见下文）：

             PrintWriter out = new PrintWriter (
                           new BufferedWriter(
                           new FileWriter("Output.html")));
        //Write the data to the file
         out.println((strBranch + "; " +
                  strCPU + "; "  + 
                  strDate.format(dteDate.getTime())) + "; " +
                  fileName + "; " +
                  fileSize + "; " + 
                  fileNum);
        //flush the data and close the output stream
         out.close();

您应该在进入 while 循环之前创建文件。

所以你的代码应该是这样的：

     PrintWriter out = new PrintWriter (new BufferedWriter(new FileWriter("Output.html")));
     while(line != null)
    {
        //perform your file operations here
    }
    out.close();

----编辑----

您已经更新了代码，但仍然不行。在第二个循环中关闭文件：

        (...)
 while (lineNum >= 9 && lineNum <= 16)
  {
      //call the MyDirectory methods to get the files name,size and number of files
      MyDirectory directory = new MyDirectory(line);
      fileName = directory.getName();
      fileSize = directory.getsize();
      fileNum = directory.getNum();
      //create the dteDate calender
      GregorianCalendar dteDate = new GregorianCalendar(year, month, day, hour, minute, second);
      //fromat the date
      SimpleDateFormat strDate = new SimpleDateFormat("MMM dd, yyyy h:m");
    //Write the data to the file
     out.println((strBranch + "; " +
              strCPU + "; "  + 
              strDate.format(dteDate.getTime())) + "; " +
              fileName + "; " +
              fileSize + "; " + 
              fileNum);
    //flush the data and close the output stream
     //################# YOU CLOSE YOUR FILE HERE:
     out.close();
     //create the necessary output for the console
      System.out.println((strBranch + "; " +
              strCPU + "; "  + 
              strDate.format(dteDate.getTime())) + "; " +
              fileName + "; " +
              fileSize + "; " + 
              fileNum);
     //move on in the loop so it's not infinte
      break;
   }    
}

当此循环下次迭代时，您仍会尝试写入文件（然后再次关闭它，即使它在上一次迭代中已关闭）。

Answer 2

您在输出文件中只看到一行，因为每次写入文件时都会覆盖该文件。

如果您必须在 while(linenum >=9 && linenum

new FileWriter("Output.html", true);

会解决你的问题。