兩個分支都在我的if-else語句中執行

Question

當我要求教師輸入時，它將正確執行，直到打印輸出為止，然后它將打印輸入800號（僅要求學生輸入）。 我無法弄清楚為什么在您輸入教師后總是會問學生特定的問題。

    public class UniversityIDApp {
public static void main(String[] args){
    // display a welcome message
    System.out.println("Welcome to the University ID application");
    System.out.println();

    Scanner sc = new Scanner(System.in);
    String choice = "y";
    while(choice.equalsIgnoreCase("y"))
    {
        // get user entries
        String userType = Validator.getString(sc,
            "Create student or faculty? (s/f):   ", "s", "f");
        String firstName = Validator.getString(sc,
            "Enter first name:   ");
        String lastName = Validator.getString(sc,
            "Enter last name:   ");
        String email = Validator.getString(sc,
            "Enter e-mail:  ");


    if (userType.equalsIgnoreCase("f"))
    {

    String department = Validator.getString(sc,
            "Enter department:   ");

       // create faculty object
       Faculty f = new Faculty() {};
       f.setFirstName(firstName);
       f.setLastName(lastName);
       f.setEmail(email);
       f.setDepartment(department);
       System.out.print("Southern Illinois University Faculty ");
       System.out.print("\nName:       " + f.getFirstName() + " " + f.getLastName() + "\n" 
       +  "Email:      "  + f.getEmail() + "\n" + "Department: " + f.getDepartment() + "\n" );
       System.out.println();
    }
    else if(userType.equalsIgnoreCase("s"));
    {

    Student s = new Student() {};
    String student800Number = Validator.getString(sc,
            "Enter your 800 number:   ");

       s.setFirstName(firstName);
       s.setLastName(lastName);
       s.setEmail(email);
       s.setStudent800Number(student800Number);
       System.out.print("Southern Illinois University Student");
       System.out.print("\nName:        " + s.getFirstName() + " " + s.getLastName() + "\n" 
  +   "Email:       "  + s.getEmail() + "\n" + "Student 800 Number:  " + s.getStudent800Number() + "\n" );
       System.out.println();

        }
        System.out.print("Continue? (y/n): ");
        choice = sc.next();
        System.out.println();
    }
}

Answer 1

您的else if子句有分號; 使它什么也不做。

...
}
   else if(userType.equalsIgnoreCase("s")); //<-- here
{
...

與此相同：

        if ( true ) {
            System.out.println("true");
        } else if ( false ) {
            ;
        }

        {
            System.out.println("false? what's going on?");
        }

如果您將開括號放在同一行（這是Java的約定），可能會更容易發現。