Java中“while”的问题

import java.io.*;
import java.util.Scanner;

public class Ex420
{
 public static void main( String args[] )
 {
  String employeeName = "";
  double workHours,excessHours,hourlyRates,grossPay;
  Scanner input = new Scanner( System.in );

  while ( employeeName != "stop" )
  {
   System.out.printf( "nInput employee name or stop to exit: " );
    employeeName = input.nextLine();
   System.out.printf( "Input working hours: " );
    workHours = input.nextDouble();
   System.out.printf( "Input hourly rates: " );
    hourlyRates = input.nextDouble();

   if ( workHours <= 40 & workHours >= 0 )
   {
    excessHours = 0;
    grossPay = hourlyRates * workHours;
    System.out.printf( "%s's gross pay is $%.2fn",employeeName,grossPay );
   }
   else if ( workHours > 40 )
   {
    excessHours = workHours - 40;
    grossPay = hourlyRates * 40 + 1.5 * hourlyRates * excessHours;
    System.out.printf( "n%s's worked for %.1f excess hours.n",excessHours );
    System.out.printf( "%s's gross pay is $%.2fn",grossPay ); 
   }
   else
   {
    System.out.printf( "Invalid input. Please try again." );
   }  
  } // end while
 } // end main
} // end class Ex420

问题是,while循环似乎不起作用.每当我输入“stop”作为employeeName时,程序就会继续.我尝试用任何其他字符串替换“停止”,它仍然无法正常工作.但是当我尝试使用“stop”初始化employeeName时,程序会立即退出,这是预期的.我在这做错了什么？

此外,在第一个循环之后,程序总是跳过询问employeeName.我尝试替换employeeName = input.nextLine(); with employeeName = input.next();它不再跳过它.我想知道,有什么办法可以让我在使用employeeName = input.nextLine()时不跳过输入;？

在此先感谢您的帮助！