java 异常详解及应用实例

public class ExceptionDemo { public static void main(String[] args) { //OutOfMemoryError内存溢出错误， int[] i = new int[1024*1024*1024]; System.out.println(i[1]);  //ArrayIndexOutOfBoundsException索引越界异常 int[] s = new int[2]; System.out.println(s[2]);   Calc calc = new Calc();  //假如我们在这里捕获异常 try {  calc.run(4, 0);  calc.run(4, -1); } catch (NegativeException e) {//必须先抛出异常的自定义子类  e.printStackTrace();  System.out.println(e.getMessage());  //throw e;//可以继续将此异常抛出 } catch (ArithmeticException e){//抛出自定义异常类的父类  e.printStackTrace();  System.out.println(e.getMessage());  //throw e; } finally {  System.out.println("finally肯定会执行到"); } //如果上面进行了异常捕获，那么代码可以继续执行，否者代码不能继续执行 System.out.println("可以执行到！");  try {  calc.run(4, -1);   } catch (NegativeException e) {  e.printStackTrace();  System.out.println(e.getMessage());  return; } finally {  System.out.println("肯定会执行的"); } System.out.println("执行不到了");//执行不到此行代码  }}/** * 自定义异常 */class NegativeException extends ArithmeticException{ public NegativeException() { } public NegativeException(String msg) { super(msg); }}interface AA{ public abstract void method();}class Calc implements AA{ //ArithmeticException其实为运行时异常(RuntimeException)，即使不进行throws声明，也可以通过编译 public int run(int m,int n)throws ArithmeticException,NegativeException{ if(n==0){  throw new ArithmeticException("除数不能为0"); }else if(n<0){  throw new NegativeException("除数不能为负数"); } int s = m/n; return s ; } @Override public void method() { try {  int p = 4/0; } catch (ArithmeticException e) {  e.printStackTrace();  throw new RuntimeException();//将异常继续抛出为运行时异常 } }}