Question

import java.util.Scanner;



public class HelloWorld 
{ 
    public static void main(String[] args)
    {
        Scanner math = new Scanner(System.in);
        System.out.println("What is 2 + 2?");
        int num = math.nextInt();
        System.out.println("Wrong."); // Displays "Wrong." no matter the answer.

        {
            Thread.sleep(2000); // Adds a timer for 2 seconds.
        }
        catch(InterruptedException e)
        {
            System.out.println("Please, try again :-)");
            }

        int num1 = math.nextInt();
        System.out.println(""); //Displays some message.
    }
}

代码应该显示＆＃34;什么是2 + 2？＆＃34;，用户输入答案，代码返回＆＃34;错误。＆＃34;不管答案是什么。暂停2秒后，代码显示＆＃34;请再试一次： - ）＆＃34;并且用户输入一个整数，代码返回一条消息。

错误发生在使用catch标记的行上。错误是：令牌上的语法错误＆＃34; catch＆＃34;，（预期，语法错误，插入＆＃34; - ＆gt; LambdaBody＆＃34;完成LambdaExpression，语法错误，插入＆＃34; AssignmentOperator Expression＆＃34;完成作业，语法错误，插入＆＃34;;＆＃34;完成声明

Answer 1

要在java中使用catch，您需要拥有try。它被称为try..catch块。请阅读文档here

因此，如下添加try应该可以解决您在此处提出的错误：

    System.out.println("Wrong."); // Displays "Wrong." no matter the answer.
    try // Looks like you missed the try here
    {
        Thread.sleep(2000); // Adds a timer for 2 seconds.
    } catch (InterruptedException e) {
        System.out.println("Please, try again :-)");
    }

Answer 2

我看不到尝试阻止。你可以使用这种方式，而不用尝试捕获。 Main方法可以抛出InterruptedException ...

 public class HelloWorld {
        public static void main(String[] args) throws InterruptedException {
            Scanner math = new Scanner(System.in);
            System.out.println("What is 2 + 2?");
            int num = math.nextInt();
            System.out.println("Wrong."); // Displays "Wrong." no matter the answer.

            {
                Thread.sleep(2000); // Adds a timer for 2 seconds.
            }

            int num1 = math.nextInt();
            System.out.println(""); //Displays some message.
        }
    }

尝试使用Thread.sleep函数，catch标记有多个错误

2 个答案: