验证以防止用户在do while循环中输入字符串或空字符串

Question

这可能很简单，但我完全被难倒了。我需要帮助防止用户在do-while循环中输入字符串或空字符串。

以下代码

 do {

    int menuItem = input.nextInt();

    switch (menuItem) {

    case 1: System.out.println("------ You have selected choice [1] - Add a employee to collection ------ ");     functions.addEmployee(); break;

    case 2: System.out.println("------ You have selected choice [2] - Edit an employee  details ------  ");  functions.editEmployee(); break;

    case 3: System.out.println("------ You have selected choice [3] - Delete an employee from collection ------  "); functions.deleteEmployee(); break;

    case 4: System.out.println("------ You have selected choice [8] - Search employee  by keyword ------  "); functions.EmpSearchByKeyword(); break;

    default:    System.out.println("Please enter in a valid integer to operate menu system (1-4)");

        }               

    } while (input.hasNextInt());

Answer 1

尝试使用while循环而不是do-while，如下所示：

     while (input.hasNextInt()){
     ....//your code
      }

Answer 2

试试此代码

do {
while(true){
   try{
       int menuItem = input.nextInt();
       break;
   }catch(Exception e){
       System.out.println("Error");
   }
}
switch (menuItem) {
   case 1: System.out.println("------ You have selected choice [1] - Add a employee to collection ------ ");     functions.addEmployee(); break;

   case 2: System.out.println("------ You have selected choice [2] - Edit an employee  details ------  ");  functions.editEmployee(); break;

   case 3: System.out.println("------ You have selected choice [3] - Delete an employee from collection ------  "); functions.deleteEmployee(); break;

   case 4: System.out.println("------ You have selected choice [8] - Search employee  by keyword ------  "); functions.EmpSearchByKeyword(); break;

   default:    System.out.println("Please enter in a valid integer to operate menu system (1-4)");
   }               

} while (input.hasNextInt());