java - 验证用户输入时无限循环

Question

我正在尝试验证输入表单中的德国邮政编码。但不知何故，我卡在了第 15 行，我的函数只是在无限循环中打印“给我输入”。

我原以为 sc_plz.nextLine() 会是一个阻塞函数，但不知为何它不是。

import View.AddressView;

import java.io.IOException;
import java.util.Scanner;

public class AddressController {
    AddressView view = new AddressView();

    public Address addAddress()throws IOException{
        //other input questions

        Scanner sc_plz = new Scanner(System.in);
        int code = 0;
        while (!validatePostcode(code))
            view.askPostcode(); //simple System.out.println("Input something")
            String postcode = sc_plz.nextLine();

            try {
                code = Integer.parseInt(postcode);
            }
            catch (NumberFormatException e){
                view.invalidData(); //warning about not got a number
            }
        //other input questions
    }

    private boolean validatePostcode(int plz) throws IOException {
        //legal postcodenumbers are between 01000 -99999
        if (1000 <= plz && plz <= 99999){
            return true;
        }
        else {
            return false;
        }
    }
}

Answer 1

您是否忘记了 while 语句的括号？就像现在一样，它将始终执行 view.askPostcode(); 中的任何操作。我想它应该是这样的:

while (!validatePostcode(code)) {
    view.askPostcode(); //simple System.out.println("Input something")
    String postcode = sc_plz.nextLine();
    try {
        code = Integer.parseInt(postcode);
    } catch (NumberFormatException e){
        view.invalidData(); //warning about not got a number
    }
}