我靠刚才写的表述没了。。。就一些判断完全权平方数，回文数神马的。

Multiplication.java

public class Multiplication{
	//输出左对齐，给定字符串长度，不足补空格
	public static String len(String str, int i){
		String tmp = "";
		if(str.length() < String.valueOf(i).length() * 4 + 8){
			for (int j = 0; j < String.valueOf(i).length() * 4 + 8 - str.length();j++ ) {
				tmp += " ";
			}
		}
		str += tmp;
		return str;
	}
	
	//输出左对齐，给定字符串长度，从头填充
	public void m1(){

		int [][] a = new int[90][];
		StringBuffer sb = new StringBuffer();
		for(int i = 0; i < a.length; i++){								
			a[i] = new int[i+1];
			for(int j =0; j < a[i].length ; j++){
			for(int k = 0; k < String.valueOf(a.length).length() * 4 + 8; k++){
				sb.append(" ");
			}
				a[i][j] = (i+1)*(j+1);
				System.out.print(sb.replace(0,((j+1)+" * "+(i+1)+" = "+a[i][j]).length(),(j+1)+" * "+(i+1)+" = "+a[i][j]));
				sb = new StringBuffer("");
			}
			System.out.println();
		}
	}
	
	//判断回文数（平方回文）
	public void m2(){		
		int n = 0;
		for (int i = 1; i <= 1.0e4 ; i++ ) {
			String s = String.valueOf(i);
			if (new StringBuffer(s).reverse().toString().equalsIgnoreCase(s) && m3(i)) {	
				System.out.println(i);
			}					
		}
		//System.out.println();
	}

	//判断完全平方数
	public boolean m3(int n){
		double fsqrt = java.lang.Math.sqrt(n);
		return (int) fsqrt == fsqrt;
	}

	//递归求n!
	public int f(int n){
		int result;
		if (n == 1) return 1;
			result = f(n - 1) * n;
			return result;
	} 

	public static void main(String [] args){	
		Multiplication mp = new Multiplication();
		//mp.m1(); 
		mp.m2();
		System.out.println(mp.f(9));
	}
}