捕获和抛出异常

异常处理机制

• 抛出异常
• 捕获异常
• 异常处理五个关键字
  • try、catch、finally、throw、throws

代码详解

Test类

public class Test {
    public static void main(String[] args) {
        int a = 1;
        int b = 0;

        //假设要捕获多个异常：从小到大
        try {
            //try监控区域

            if(b == 0){
                //throw throws
                throw new ArithmeticException();//主动地抛出异常
            }

            System.out.println(a/b);
        }catch (ArithmeticException e){
            //catch（想要捕获的异常类型）捕获异常
            System.out.println("程序出现异常，变量b不能为0");
        }catch (Exception e){
            System.out.println("Exception");
        }catch (Throwable throwable){
            System.out.println("Throwable");
        } finally {
            //处理善后工作
            System.out.println("finally");
        }
        //finally——可以不要finally,——假设IO,资源关闭等
    }
}

Test2类

public class Test2 {
    public static void main(String[] args) {
        int a = 1;
        int b = 0;

        //Ctrl + Alt + T
        try {
            System.out.println(a/b);
        } catch (Exception e) {
            e.printStackTrace();//打印错误的栈信息
        } finally {
        }
    }
}

Test3类

public class Test3 {
    public static void main(String[] args) {
        new Test3().test(1,0);
    }

    //假设这方法中，处理不了这个异常。方法上抛出异常
    public void test(int a, int b) /*throws ArithmeticException*/{
        if(b == 0){
            //throw throws
            throw new ArithmeticException();//主动地抛出异常,一般在方法中使用
        }
        System.out.println(a/b);
    }
}