虽然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循环打印到控制台和html文件。但是，即使它打印到控制台，该程序也只会将最后一行打印到html文件。这里是一个应该打印从文本文件中提取的线9中的信息16

//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); 
    } 

} 

编辑我的循环代码：通过咨询在发布的答案我现在有我的一切，但有即时输出一个困难的时间格式化它的HTML文件具有所有的行没有间距连在一起我试着用“\ n”在我的输出结束，但然后我的代码不编译，因为它说null不允许有任何人知道如何当它不会让我把“\ n”放在我的打印方法的末尾时，将其格式化为行？

我不确定这是否代码太多或不足以解决问题，如果我应该添加任何东西到我的文章或拿出任何东西只是让我知道。

Answer 1

这是相当明显的 - 创建文件每次while循环迭代（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(); 

进入while循环，而不是之前，您应该创建文件。

所以，你的代码看起来应该像：

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

---- ----编辑

你更新了你的代码，但它仍然不能确定。你关闭了文件第二循环内：

当下次这个循环迭代你还是试着写信给你的文件（然后再次关闭它，即使它是在先前的迭代关闭）。

Answer 2

在输出文件中只看到一行，因为每次写入文件时都覆盖该文件。

新的FileWriter（ “Output.html”，真正：

如果你需要创建而内的PrintWriter（LINENUM> = 9 & & LINENUM < = 16）循环，在追加模式打开文件）;

将解决您的问题。