在JAVA上打开文件

Question

import java.util.Formatter;
import java.util.Scanner;

public class JavaApplication3 {

   public static void main( String[] args ) throws Exception
   {
      Formatter output = new Formatter( "clients.txt" ); // open the file
      Scanner input = new Scanner( System.in ); // reads user input

      int accountNumber; // stores account number
      String firstName; // stores first name
      String lastName; // stores last name
      double balance; // stores account balance

      System.out.printf( "%s\n%s\n%s\n%s\n\n",
         "To terminate input, type the end-of-file indicator ",
         "when you are prompted to enter input.",
         "On UNIX/Linux/Mac OS X type <ctrl> d then press Enter",
         "On Windows type <ctrl> z then press Enter" );

      System.out.printf( "%s\n%s", 
         "Enter account number (> 0), first name, last name and balance.",
         "? " );

      while ( input.hasNext() ) // loop until end-of-file indicator
      {
         // retrieve data to be output
         accountNumber = input.nextInt(); // read account number
         firstName = input.next(); // read first name
         lastName = input.next(); // read last name
         balance = input.nextDouble(); // read balance

         if ( accountNumber > 0 )
         {
            // write new record
            output.format( "%d %s %s %.2f\n", accountNumber, 
               firstName, lastName, balance );
         } // end if
         else
         {
            System.out.println(
               "Account number must be greater than 0." );
         } // end else

         System.out.printf( "%s %s\n%s", "Enter account number (>0),",
            "first name, last name and balance.", "? " );
      } // end while

      output.close(); // close file
   } // end main
} // end class CreateTextFile

but when go to file locetion and open the txt file thre is not any thing in there.i use windows and my problem is with endenging the file i think..please help me with how to write on a file in java.tnx

Answer 1

The output from a java.util.Formatter is not written immediately. Call flush() and the waiting data will be written immediately.

   if ( accountNumber > 0 )
     {
        // write new record
        output.format( "%d %s %s %.2f\n", accountNumber, 
           firstName, lastName, balance );
           output.flush();//missing this line
     }

Answer 2

java.util.Formatter will not write until flush() method is called.
    if ( accountNumber > 0 ){
    // write new record
    output.format( "%d %s %s %.2f\n",accountNumber,firstName,lastName,balance );
    output.flush(); // this is missed.
    } // end if`enter code here`