Validate if a given string is numeric.
Some examples:"0" => true" 0.1 " => true"abc" => false"1 a" => false"2e10" => true
Note: It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one.
解题思路：
本题边界条件颇多"1.", ".34","1.1e+.1"也是正确的。解题方法是先trim一下，然后按照e进行划分，然后分别对e前后进行判断JAVA实现如下：
public boolean isNumber(String s) {
s = s.trim();
String[] splitArr = s.split("e");
if (s.length() == 0 || s.charAt(0) == 'e'
|| s.charAt(s.length() - 1) == 'e' || splitArr.length > 2)
return false;
for (int k = 0; k < splitArr.length; k++) {
String str = splitArr[k];
boolean isDecimal = false;
if (str.charAt(0) == '-' || str.charAt(0) == '+')
str = str.substring(1);
if (str.length() == 0)
return false;
for (int i = 0; i < str.length(); i++) {
if ('0' <= str.charAt(i) && str.charAt(i) <= '9')
continue;
else if (str.charAt(i) == '.' && !isDecimal) {
if (k == 0 && str.length() > 1)
isDecimal = true;
else
return false;
} else
return false;
}
}
return true;
}