java - 有没有办法根据字符串测试 int ？ ( java )

Question

我正在尝试编写一个 if/else 来测试用户输入的整数。如果他们输入一个 int，程序就会继续。如果他们输入其他内容，程序会生成一条错误消息，要求输入正确的信息。这是在球场的任何地方吗？

import java.util.Scanner;

public class test {
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        int [] foo;
        foo = new int[3];

        foo[0]=1;
        foo[1]=2;
        foo[2]=3;

        System.out.print("Make a choice between 0 and 2: ");
        int itemChoice = keyboard.nextInt();

        if (itemChoice != foo) {  
           System.out.print("Not a valid choice");  
        }  
        else {  
           System.out.print("Valid choice. You picked " + itemChoice);
        }  
    }
}

我收到此错误:

 required: int
 found:    boolean
 test.java:17: error: incomparable types: int and int[]
        if (itemChoice != foo) {  

Answer 1

尝试以下方法来验证您的输入:

Scanner.hasNextInt()

int itemChoice =0;
while(true){
    if(keyboard.hasNextInt()){    
        itemChoice = keyboard.nextInt();    
        // Do something.
        break;
    }
    else{    
        System.out.print("Not a valid choice Try again");
        continue;

    }

}