Java扫描器:如何防止进入垃圾邮件

Question

我有一个用户输入验证函数:

public int UserChoiceValidate() {
Scanner sc = new Scanner(System.in);
int choice;
do {
System.out.print("Please enter your choice: ");
while (!sc.hasNextInt()) {
System.out.print("Input invalid, please retry: ");
sc.nextLine(); // consume left over
}
choice = sc.nextInt();
if (choice <= 0 || choice > 5) {
System.out.println("Choice not included, please retry");
}
} while (choice <= 0 || choice > 5);
return choice;
}

代码将重复

Input invalid, please retry:输入无效，please retry:输入无效，please retry:

当我垃圾输入然后键入无效的输入时

我如何修复这个错误，而不必重写它为读取String而不是int。我有相当多的函数具有相同的结构，我希望避免重写它们。

Answer 1

我不确定你所说的"将其重写为字符串验证"是什么意思，你目前忽略了用户提供的不是int的任何输入;如果您想处理"，请输入spam"特别的，你可以这样写

System.out.print("Please enter your choice: ");
while (!sc.hasNextInt()) {
String line = sc.nextLine();
if (line.isEmpty()) {
continue;
}
System.out.print("Input invalid, please retry: ");
}