java - 我想在我的文件系统中保存多个数据

Question

`

    NumberFormat currency = NumberFormat.getCurrencyInstance(Locale.US);


    String employeeName;    
    float hoursWorked;          
    float hourlyRate;           
    float basepay;          
    float netpay;
    float overtime = 0;
    int numberofemp= 0;
    final JPanel panel = new JPanel();

        System.out.println( "Assignement 2\n\n");   
            numberofemp = Integer.parseInt(JOptionPane.showInputDialog("Enter No of Employee"));

     int[] arrayList= new int[numberofemp];
       for (int i = 0; i < arrayList.length; i++)

      {
             employeeName = JOptionPane.showInputDialog("Enter the employee name:");

       do
        {
           hourlyRate = Float.parseFloat(JOptionPane.showInputDialog("Enter the number of Hourly Rate :"));

           if (hourlyRate < 8)
                {   
                JOptionPane.showMessageDialog(panel, "The hourly rate must be 8 an hour", "Error", JOptionPane.ERROR_MESSAGE);
                }
              }
       while ( hourlyRate < 8 ); 

           do
             {
               hoursWorked = Float.parseFloat(JOptionPane.showInputDialog("Enter the number of hours worked:"));

            if (hoursWorked >60)
            {
                    JOptionPane.showMessageDialog(panel, "The number of hours worked must be under 60", "Error", JOptionPane.ERROR_MESSAGE);                     
            }
          }
        while ( hoursWorked >60);


                    if (hoursWorked > 40)
                        {
                        overtime = (float) (  (hoursWorked - 40) *(hourlyRate * 1.5));
                        }

                        else
                        { basepay = hoursWorked * hourlyRate;

                        }
        netpay  =  basepay + overtime;          

        System.out.println( "\n\nEmployee Name: " + employeeName);      
         System.out.println( "Hours Worked: " + hoursWorked );
         System.out.println( "Base Pay: " + currency.format(basepay) );
          System.out.println( "Overtime Pay: " + currency.format(overtime)); 
           System.out.println( "Total Pay: " + currency.format(netpay)); 
            System.out.println( );


 try
  {
     PrintWriter prst;
         prst = new PrintWriter( "C://Users/tushar/Desktop/Workspace/Assignment_2/out.txt" );
              prst.println( "\n\nEmployee Name: " + employeeName);
                prst.println( "\n\nBasePay: " + basepay);
                  prst.println( "\n\nOvertime Pay: " + overtime);
                    prst.println( "\n\nTotal pay: " + netpay);
                       prst.close();

                                     }
 catch (Exception e)
 {
         System.err.println ("Error writing to file");
 }                      



       }
     }  }

嗨，我的代码有一点问题。在我的代码中，我只能保存最后的数据列表。在我的文件系统中，我想保存多个数据。所以任何人都可以帮助我如何将尽可能多的数据保存到我的文件系统中。

Answer 1

将 PrintWriter 初始化放在 for 循环之外，并使用 close 方法在 for 循环结束之外关闭 PrintWriter，如果您想再次使用该文件并追加到它以便旧数据不被删除，请使用 FileOutputStream(prst, true)，如 MadProgrammer 所建议的。

   PrintWriter prst = new PrintWriter( "C://Users/tushar/Desktop/Workspace/Assignment_2/out.txt" );
   int[] arrayList= new int[numberofemp];
   for (int i = 0; i < arrayList.length; i++)
   {
     ........................
     try
     {
      prst.println( "\n\nEmployee Name: " + employeeName);
      prst.println( "\n\nBasePay: " + basepay);
      prst.println( "\n\nOvertime Pay: " + overtime);
      prst.println( "\n\nTotal pay: " + netpay);

     }
     catch (Exception e)
     {
       System.err.println ("Error writing to file");
     }                      
  }
  prst.close();