如何循环 Try 块直到没有捕获到异常？

Question

如何循环遍历 Try-Catch 的 Try 块部分，直到没有捕获到异常？

例如；您将分母输入为 0（除以 0），捕获并处理 ArithmeticException，并且 Try 块再次为运行（要求您再次输入分子和分母）。当没有捕获到任何东西时，程序停止。

import java.util.InputMismatchException;
import java.util.Scanner;

public class Activity {

    public static void main(String[] args) {

        Fraction sampleFraction = new Fraction(8,3);
        
        Scanner scan = new Scanner(System.in);

            try {
                System.out.print ("Enter the numerator:  ");
                sampleFraction.setNumerator(scan.nextInt());        
                System.out.print ("Enter the denominator:  ");
                sampleFraction.setDenominator(scan.nextInt());  
                
                System.out.println ("The fraction " + sampleFraction.getNumerator() + "/" +
                        sampleFraction.getDenominator() + " is equal to " + sampleFraction.toMixedNumber());
            }
            catch (ArithmeticException e) {
                System.out.println("You can't divide by zero! \n");
            }
            catch (InputMismatchException e) {
                System.out.println("Please enter whole numbers (Integers) only! \n");
            }
            catch (Exception e) {
                System.out.println("An unexpected exception was caught; please try again! \n");
            }
                
                scan.close();
        }
        
    }

这只是 driver/main class。如果需要，我可以提供分数 class，尽管它只处理所有计算和打印数学的方法。

Answer 1

用循环包围 try/catch，并在 try 块的末尾中断：

while (true) {
  try {
    // Do things that might throw exceptions...

    // This breaks out of the `while` loop.
    break;
  } catch (ArithmeticException e) {
    // ...
  } catch (InputMismatchException e) {
    // ...
  } /* etc */

  // Unless we break/return in the catch blocks, the loop will execute again.
}

话虽如此，最好首先避免异常。例外是为了处理异常的事情；如果你知道是什么原因导致抛出异常，你也许可以避免它。

例如，当您尝试除以零时会出现 ArithmeticException：与其依赖捕获异常，不如先检查分母不为零：

int denominator = scan.nextInt();
if (denominator == 0) {
  System.out.println("You can't divide by zero! \n");
  continue;
}
sampleFraction.setDenominator(denominator);

如何循环 Try 块直到没有捕获到异常？

How can I loop the Try block until no exceptions are caught?

java

exception

try-catch