两个大数相乘

import javax.swing.text.rtf.RTFEditorKit;

public class LargeNumMult{
	public static void main(String[] args) {
		String a="424242343242";
		String b="65757567001";
		String finalResult = "0";
		for(int i = b.length()-1,h=0; i >= 0; i--,h++){
			int bSingle = Integer.valueOf(b.substring(i, i+1));
			StringBuilder result = new StringBuilder();
			int remainder = 0;
			for(int j = a.length()-1; j >= 0; j--){
				int singleNum = Integer.valueOf(a.substring(j, j+1));
				int singleResult = bSingle*singleNum+remainder;
				result.append(singleResult%10);
				if (j==0) {
					result.append(singleResult/10);
				}
				remainder = singleResult/10;
			}
			StringBuilder singleResult = result.reverse();
			for(int k = 0; k < h ; k++){
				singleResult.append(0);
			}
			finalResult = add(singleResult.toString(), finalResult).toString();
		}	
		System.out.println(finalResult.replaceAll("0*", ""));	
	}
	
	static StringBuilder add(String s1, String s2){
		if (s1.length()>s2.length()) {
			StringBuilder stringBuilder2 = new StringBuilder(s2).reverse();
			for(int i = 0; i=0; i-- ){
			int singleNum1 = Integer.valueOf(s1.substring(i, i+1));
			int singleNum2 = Integer.valueOf(s2.substring(i, i+1));
			int singleResult = singleNum1+singleNum2+addHightPosition;
			addResult.append(singleResult%10);
			addHightPosition = singleResult/10;
			if (i==0) {
				addResult.append(addHightPosition);
			}
		}
		addResult.reverse();
		
		System.out.println("add "+addResult);
		return addResult;
	}
}