Java 輸入驗證設計

Question

這里是新手，請放輕松...

清除下面的輸入驗證邏輯的 Java/OOP 方法是什么？ 在整個main方法中多次執行檢查以確保已輸入int 。 多次復制輸入驗證行感覺很臟。 注意每個輸入的問題變化。

我假設一種解決方案是將keyInput和問題（字符串）傳遞給完成驗證並在輸入正確時返回keyInput.nextInt的方法。

非新手會做什么？

謝謝你。

public static void main(String[] args) {
        
        Scanner keyInput = new Scanner(System.in);
        int level = 0;
        boolean badInput = true;
        int answer = 0;
                
        while (badInput) {
            
            System.out.print("Enter a level between 1 and 4: ");
            
            if (!keyInput.hasNextInt()) {
            
                System.out.println("*** Input is not an integer! ***\n");
                keyInput.next();
                continue;
            
            } 
            
            level = keyInput.nextInt();
    
            if (level < 1 || level > 5) {
                
                System.out.println("*** Number is not between 1 and 4! ***\n");
                continue;
                
            }
            
            badInput = false;
            
        }
                
        MathChallenge game = new MathChallenge(level);

        badInput = true;
        
        while (badInput) {
            
            System.out.print("Enter the sum of " + game.getArray() + ": ");
            if (!keyInput.hasNextInt()) {
            
                System.out.println("*** Input is not an integer! ***\n");
                keyInput.next();
                continue;
            
            }
            ...

Answer 1

創建一個包含重復代碼的方法，並將任何變量片段作為 arguments 傳遞給該方法。

例如：

public int getNumber(Scanner keyInput, String prompt, int min, int max) {
    while (true) {
        System.out.print(prompt);
 
        if (!keyInput.hasNextInt()) {
            System.out.println("*** Input is not an integer! ***\n");
            keyInput.next();
            continue;
        } 
            
        number = keyInput.nextInt();
        if (number < min || number > max) {
            System.out.println("*** Number is not between " + min + " and " + max + "! ***\n");
            continue;
        }
        return number;
    }
}

然后這樣稱呼它：

public static void main(String[] args) {
    Scanner keyInput = new Scanner(System.in);
    int level = getNumber(keyInput, "Enter a level between 1 and 4:", 1, 4);
    MathChallenge game = new MathChallenge(level);
    int sum = getNumber(keyInput, ""Enter the sum of " + game.getArray() + ": ", 0, 100);
    // ...
}