Java for LintCode 颠倒整数

public int reverseInteger(int n) {
Boolean isNeg = n >= 0 ? false : true;
StringBuilder sb = new StringBuilder(n+"");
if (isNeg)
sb.delete(0, 1);
sb = sb.reverse();
long res = 0;
for (int i = 0; i < sb.length(); i++)
res = res * 10 + sb.charAt(i) - '0';
if (res > Integer.MAX_VALUE)
return 0;
return isNeg ? -(int) res : (int) res;
}