正在关闭BufferedWriter擦除写入文件的所有文件数据吗？

问题描述 投票：0回答：2

我正在从ObjectInputStream获取连续数据，该数据是使用BufferedWriter对象写入文件中的。我正在检查文件大小，并不断增加。现在，一旦我停止使用while(true)中断false方法，并继续运行该方法，我就关闭了BufferedWriter对象。执行此操作后，所有写入文件的数据都会丢失。 

private void appendFile(JLabel jLab0x28, Socket client)
    {   
        try
        {   
            if(!continueMe)
            {   
                fileOut.close();
                fileOut = null;
                in.close();
                System.gc();
                jLab0x28.setText("<html> <font color='red'> Socket is closed  "+client.isClosed()+" </font> </html>");
                System.out.println("File size after discontinuing  "+
                        humanReadableByteCount(new File("C:\\ISSUE124_Resolved.txt").length(), true) );
            }

            if(!client.isClosed())
            {   
                try
                {   
                    String data = in.readObject().toString();
                    System.out.println("File size is  "+
                            humanReadableByteCount(new File("C:\\ISSUE124_Resolved.txt").length(), true) );
                    fileOut.append(data);
                    fileOut.flush();
                }
                catch (EOFException exp)
                {   
                    continueMe = true;
                    exp.printStackTrace();
                    System.out.println("A Stream has finished "+exp.toString()+"\n");
                }
                catch (ClassNotFoundException exp) 
                {
                    exp.printStackTrace();
                    System.err.println(exp.toString());
                    continueMe = false;
                }
            }
        }
        catch(IOException exp)
        {
            try 
            {
                fileOut.close();
            } 
            catch (IOException e) 
            {
                e.printStackTrace();
            }
            exp.printStackTrace();
            System.err.println("Exception "+exp.toString());
            jLab0x28.setText(exp.getMessage());
            continueMe = false;
        }
    }
public static String humanReadableByteCount(long bytes, boolean si) {
        int unit = si ? 1000 : 1024;
        if (bytes < unit) return bytes + " B";
        int exp = (int) (Math.log(bytes) / Math.log(unit));
        String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp-1) + (si ? "" : "i");
        return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
    }

记录的数据：

File size is  118.3 kB
File size is  118.4 kB
File size is  118.5 kB
File size is  118.7 kB
File size is  118.8 kB
File size is  118.9 kB
File size is  119.1 kB
File size is  119.2 kB
File size is  119.3 kB
Done
Closed Socket connection from client
File size after discontinuing  0 B
java bufferedwriter objectinputstream
2个回答
1
投票

您需要关闭输出流。当前，您正在catch子句中执行此操作，如果未遇到IOException（并且您不希望这样做），则无法达到此条件]

catch(IOException exp)
        {
            try 
            {
                fileOut.close();
            } 
  ...

像这样修改您的代码

catch(IOException exp)
        {

            exp.printStackTrace();
            System.err.println("Exception "+exp.toString());
            jLab0x28.setText(exp.getMessage());
            continueMe = false;
        }
try 
{
     fileOut.close();
 } 
 catch (IOException e) 
 {
      e.printStackTrace();
  }
0
投票

[好，这里我使用了BufferedWriter的FileWriter对象intsead，现在我的文件数据没有被擦除。所有代码都是一样的，只是对象的更改对我有用。 

public static String humanReadableByteCount(long bytes, boolean si) {
        int unit = si ? 1000 : 1024;
        if (bytes < unit) return bytes + " B";
        int exp = (int) (Math.log(bytes) / Math.log(unit));
        String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp-1) + (si ? "" : "i");
        return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
    }

    private void appendFile(JLabel jLab0x28, Socket client)
    {   
        try
        {   
            if(!continueMe)
            {   
                //fileOut.close();
                //fileOut = null;
                fw.close();
                fw = null;
                in.close();
                System.gc();
                jLab0x28.setText("<html> <font color='red'> Socket is closed  "+client.isClosed()+" </font> </html>");
                System.out.println("File size after discontinuing  "+
                        humanReadableByteCount(new File("C:\\ISSUE124_Resolved.txt").length(), true) );
            }

            if(!client.isClosed())
            {   
                try
                {   
                    String data = in.readObject().toString();
                    System.out.println("File size is  "+
                            humanReadableByteCount(new File("C:\\ISSUE124_Resolved.txt").length(), true) );
                    fw.write(data);
                    fw.flush();
                    //fileOut.write(data);
                    //fileOut.flush();

                }
                catch (EOFException exp)
                {   
                    continueMe = true;
                    exp.printStackTrace();
                    System.out.println("A Stream has finished "+exp.toString()+"\n");
                }
                catch (ClassNotFoundException exp) 
                {
                    exp.printStackTrace();
                    System.err.println(exp.toString());
                    continueMe = false;
                }
            }
        }
        catch(IOException exp)
        {
            try 
            {
                //fileOut.close();
                fw.close();
            } 
            catch (IOException e) 
            {
                e.printStackTrace();
            }
            exp.printStackTrace();
            System.err.println("Exception "+exp.toString());
            jLab0x28.setText(exp.getMessage());
            continueMe = false;
        }
    }


File size is  1.8 MB
File size is  1.8 MB
File size is  1.8 MB
Done
Closed Socket connection from client
File size after discontinuing  1.8 MB
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