删除Java中的临时文件

Question

Am having the below code , creating a Temp file and read that and deleting the file. But after deletion also file available to read .Please help to find wrong with my code....

public static void main(String args[]) throws Exception
    {                   
        Calendar mSec = Calendar.getInstance();
        String fileName="hubname_"+"msgname_"+mSec.getTimeInMillis();
        String str ="Hello How are you doing .......";
        System.out.println("fileName :"+fileName);

        File f = File.createTempFile(fileName, ".xml");
        FileWriter fw = new FileWriter(f);
        fw.write(str);
        fw.flush();
        fw.close();

        printFileContent(f);
        f.delete();
        printFileContent(f);

    }
  public static void printFileContent(File f)throws Exception
  {
      BufferedReader reader = new BufferedReader( new FileReader(f));
      String         line = null;
      StringBuilder  stringBuilder = new StringBuilder();
      String         ls = System.getProperty("line.separator");

      while( ( line = reader.readLine() ) != null ) {
          stringBuilder.append( line );
          stringBuilder.append( ls );
      }

      System.out.println("stringBuilder.toString() :"+stringBuilder.toString());
  }

Output :

fileName :hubname_msgname_1358655424194
stringBuilder.toString() :Hello How are you doing .......

stringBuilder.toString() :Hello How are you doing .......

Answer 1

You should close reader in printFileContent. File.delete cannot delete an opened file (at least on Windows, see Keith Randall's comment below) in which case it returns false. You could check if delete was successful

if (!f.delete()) {
    throw new IOException("Cannot delete " + f);
}

The following comment was added to File.delete API in Java 7

Note that the Files class defines the delete method to throw an IOException when a file cannot be deleted. This is useful for error reporting and to diagnose why a file cannot be deleted.

Answer 2

public static void printFileContent(File f)throws Exception
  {
      BufferedReader reader = new BufferedReader( new FileReader(f));
      String         line = null;
      StringBuilder  stringBuilder = new StringBuilder();
      String         ls = System.getProperty("line.separator");

      while( ( line = reader.readLine() ) != null ) {
          stringBuilder.append( line );
          stringBuilder.append( ls );
      }

      System.out.println("stringBuilder.toString() :"+stringBuilder.toString()); 

   if(reader != null){
     reader.close();
    }

  }