字符串数字转换成整型(不用Integer.valueOf()方法)

/** * 把一个字符串数字转换成整型，禁止使用Integer.valueOf(i)方法 * @author alen * */ public class ChangeStr { public static int Convert(String str) throws Exception { int a = 0,i = 0; char[] cStr = str.toCharArray(); //判断是否是负数 if (cStr.length > 0 && cStr[0] == '-') { i = 1; } for (; i < cStr.length; i++) { if ('0' > cStr[i] || cStr[i] > '9') { throw new NumberFormatException(); } a = a * 10 + Character.digit(cStr[i], 10); } if (cStr.length > 0 && cStr[0] == '-') { a = -a; } return a; } /** * @param args * @throws Exception */ public static void main(String[] args) throws Exception { // TODO Auto-generated method stub Convert("23456"); } }