这里我有代码，我会解释我的每一个问题。

public static void main(String[] args) {
    String choice = null ;
   Scanner asmnt2=new Scanner(System.in);
         do {
          System.out.println("Enter you're name:");
   String name =asmnt2.nextLine();
   System.out.println("Enter you're Phone number:");
   String phone =asmnt2.nextLine();
   System.out.println("Enter you're id number :");
   String id =asmnt2.nextLine();
       person data = Employee( name,  phone,  id);
    person data2= Customer(name , phone ,id);

好吧，这是“雇员”和“客户”两个词中的一个错误，建议我为它们中的每一个都指定一个方法。

data.setSalary(salary);
       System.out.println("Choose from the list below :");
        System.out.println("1. show Employee information and salary for six months");
         System.out.println("2. show customer information");
          System.out.println("3. Exit");
 if(choice=="1"){
              System.out.println("Enter you're Salary :");
       String salary =asmnt2.nextLine();
                      System.out.println("Employee{ " + Employee.toString());
          }else if(choice =="2"){
              System.out.println("Customer{ " + Customer.toString());
          }else{
              System.out.println("Wrong entry, please try again");
          }
          } while(choice=="3");

    }

我添加这个部分是因为它显示我添加了一个“scanner”，它显示我希望用户填充值这可能是错误的原因，我还不知道。

class person{
                private String name;
                private String phone;
                private int id;

                public person(String nm, String ph, int ID){
                    name=nm;
                    phone=ph;
                    id=ID;

            }
                public String toString(){
                    return "name :"+ name + "phone :"+ phone + "ID :" + id;
            }
             }

         class Employee extends person{
            private double salary;
            private double S;

        class Customer extends person{
            private double sales;

            public Customer(String nm, String ph, int ID){
            super(nm,ph,ID);
            sales=0.0;
         }   

        class Employee extends person{
        private double salary;
        private double S;

        public Employee(String nm, String ph, int ID){
        super(nm,ph,ID);
        salary=0.0;
        }
        }