异常

异常

class ExceptionDemo {public static void main(String[] args) {Demo d = new Demo();try{int x = d.div(4,0);System.out.println(x);}catch (Exception e){System.out.println("zzz");System.out.println(e.getMessage());//异常信息System.out.println(e.toString());e.printStackTrace();//异常名称 异常信息 异常出现的位置}}}class Demo{int div(int a, int b)throws Exception {return a/b;}}

多异常

class ExceptionDemo1 {public static void main(String[] args) {Demo d = new Demo();try{int x = d.div(3,1);System.out.println(x);}catch (ArithmeticException e){System.out.println(e.toString());System.out.println("被零除");}catch(ArrayIndexOutOfBoundsException e){System.out.println(e.toString());System.out.println("角标越界");}}}class Demo{int div(int a, int b)throws ArithmeticException,ArrayIndexOutOfBoundsException {int [] arr = new int[a];System.out.println(arr[4]);return a/b;}}

自定义异常

class Demo{int div(int a, int b)throws FuException {if(b<0)throw new FuException("zzzzz",b);return a/b;}}class FuException extends Exception{private int value;FuException(){}FuException(String msg,int value){super(msg);this.value = value;}public int getValue(){return value;}}class ExceptionDemo2 {public static void main(String[] args) {Demo d = new Demo();try{int x = d.div(4,-1);System.out.println(x);}catch (FuException e){System.out.println(e.toString());System.out.println("错误是："+e.getValue());}}}