exception3.java

课本异常处理实例。各种异常处理

//捕获多个异常
public class Exception3
{
	public static int Sum(int n)
	{
		if (n < 0)
			throw new IllegalArgumentException("n应该为正整数！");
		int s = 0;
		for (int i=0; i<=n; i++) s = s + i;
			return s;
	}
	public static void main(String args[])
	{
		try
		{
			int n = Integer.parseInt(args[0]);//注意要在DOS命令行中带参数运行
			System.out.println(Sum(n));//注意调用了含有异常的方法Sum()
		}
		catch (ArrayIndexOutOfBoundsException e)
		{
			System.out.println("命令行为："+"java Exception3 <number>");
		}
		catch (NumberFormatException e2)
		{
			System.out.println("参数<number>应为整数!");
		}
		catch (IllegalArgumentException e3)
		{
			System.out.println("错误参数:"+e3.toString());//返回异常的信息
		}
		finally
		{
			System.out.println("程序结束!");
		}
	}
}