用string类型进行十进制加法计算

public static int getChar(String n1,int pos){
        int a=0;
        char c_a;
        if(pos<n1.length()){
            c_a = n1.charAt(n1.length()-pos-1);
            a = c_a-'0';//实际上这一步就不叫字符串加减了，顶多算模拟位数相加
        }
        return a;
    }
    public static String addNumericStrings(String n1,String n2){
        String result = "";
        String A = "";
        int len = n1.length()>n2.length()?n1.length():n2.length();
        int a,b;
        int flag = 0;
        char c_a,c_b;
        for(int i=0;i<len;i++){
            a=getChar(n1,i);
            b=getChar(n2,i);
            int v3=flag+a+b;
            if(v3>=10){
                A=String.valueOf(v3-10);
                flag=1;
            }else{
                A=String.valueOf(v3);
                flag = 0;
            }
            result=A+result;
        }
        return result;
    }
    /**
     * @param args
     */
    public static void main(String[] args) {
        String k = addNumericStrings("2986","14");
        System.out.println(k);
    }