public class StringToInt {        public static int stringToInt (String str){        char[] num = str.toCharArray();//得到各个字符的char        int result = 0;        for(int i = 0; i < num.length; i++){            if(num[i]>57||num[i]<48){//0~9对应的Ascall码                System.out.println("数据格式错误，转换失败！！！");                throw new NumberFormatException();            }else{                result+=(num[i]-48)*(Math.pow(10, num.length-i-1));            }        }        return result;    }        public static void main(String[] args) {        String str = "612345";        //String str="612346a";//错误格式测试        int sum=stringToInt(str);        System.out.println(sum);    }    }