Question

我想在下面的代码中创建一个自定义异常来处理可能的除零，但是编译器声明我声明的异常是未报告的。很抱歉这类问题，但我是java和面向对象编程的初学者。

public class Exception_Tester {
    public static void main(String args[]) { 
        Exception_Tester et = new Exception_Tester(); 
        int x1; 
        int x2; 
        x1 = 5; 
        x2 = 0;
        et.printResults(x1, x2);       
       } 
    void printResults(int a, int b) throws ArithmeticException { 
        System.out.println("Add: "+(a+b)); 
        System.out.println("Sub: "+(a-b)); 
        System.out.println("Mul: "+(a*b)); 
        if(b != 0)
            System.out.println("Div: "+(a/b));
        else{ 
        Exception myException = new ArithmeticException("You can't divide by zero!");
        throw myException;
        } 
    }
}

编译器错误：未报告的异常java.lang.Exception;必须被抓住或宣布被抛出

Answer 1

问题是你在方法中抛出了未声明的Exception：

Exception myException = new ArithmeticException("You can't divide by zero!");
throw myException; //here you throw Exception

您可以通过以下任何方式解决此问题：

声明您的方法抛出Exception：

void printResults(int a, int b) throws Exception {
    //...
}

按原样抛出新的ArithmeticException：

//Exception myException = new ArithmeticException("You can't divide by zero!");
throw new ArithmeticException("You can't divide by zero!");

请注意，ArithmeticException从RuntimeException延伸，因此您的方法无需声明它。所以，你的代码可能是这样的：

void printResults(int a, int b) { 
    System.out.println("Add: "+(a+b)); 
    System.out.println("Sub: "+(a-b)); 
    System.out.println("Mul: "+(a*b)); 
    if(b != 0) {
        System.out.println("Div: "+(a/b));
    } else {
        throw new ArithmeticException("You can't divide by zero!");
    }
}

自定义抛出异常会导致意外编译错误

1 个答案: