When both the output and input streams are opened, the text content disappears.

When both the output and input streams are opened, the text content disappears.
When you open both the output and input streams for a text file, if you use the API accidentally, you will find that the output stream output is empty for the following reasons:

Public static void main (String [] args) {FileInputStream FD = null; FileOutputStream fos = null; try {File file = new File ("D: // test.txt "); FS = new FileInputStream (file);/*** new FileOutputStream (file) * new FileOutputStream (file, true) append mode * if no append mode is selected, the contents of the original file will be cleared, such as FileWriter (which is internally maintained by FileOutputStream... */Fos = new FileOutputStream (file); byte [] B = new byte [1024]; int index = 0; while (index = FCM. read (B)> = 0) {System. out. println (new String (B, 0, index);} // "\ r \ n" is the line break fos. write ("\ r \ ntest ". getBytes ();} catch (FileNotFoundException e) {e. printStackTrace ();} catch (IOException e) {e. printStackTrace ();} finally {try {if (FS! = Null & fos! = Null) {fos. close (); FCM. close () ;}} catch (IOException e) {e. printStackTrace ();}}}