代码如下
public class Fibonacci{
    public static void main(String args[]){
        int n = Integer.parseInt(args[0]);
        int n1 = 1;//第一个数
        int n2 = 1;//第二个数
        int sum = 0;//和
        if(n<=0){
            System.out.println("参数错误!");
            return;
        }
        if(n<=2){
            sum = 1;            
        }else{
            for(int i=3;i<=n;i++){
                sum = n1+n2;
                n1 = n2;
                n2 = sum;
            }
        }
        System.out.println(sum);
    }
}
运行后显示Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
    at com.liushiqi.Fibonacci.main(Fibonacci.java:5)   这是怎么回事呢？？