要求实现方法public String addTwoBigNumber(String s1,string s2) 大数相加，注意处理异常

import java.math.BigInteger;import java.util.Scanner;/** * 要求实现方法public String addTwoBigNumber(String s1,string s2) 大数相加，注意处理异常 * * public class Test{ * public String addTwoBigNumber(String s1,string s2) { * return ""; } * * public static void main(String[]
args) { * Test test = new Test(); * test.addTwoBigNumber("123456789","987654321") * } * } * @author zxy * */public class Num09 {public String addTwoBigNumber(String s1,String s2){String result=null;if(isBigNumber(s1)&&isBigNumber(s2)){BigInteger bi1=new BigInteger(s1);BigInteger
bi2=new BigInteger(s2);result=bi1.add(bi2).toString();}else{System.out.println("输入的 字符不正确，必须都为0-9的数字");return "";}return result;}public static boolean isBigNumber(String str){String regex="^[0-9]*$";if(str.matches(regex)){return true;}else{return false;}}
public static void main(String[] args) {Num09 num=new Num09();String result=num.addTwoBigNumber("123456789","987654321");System.out.println(result);}}