题目：
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.
思路：
正则表达式
package others; public class ValidNumber { public boolean isNumber(String s) { return s.matches("^\\s*[+-]?(\\d+|\\d*\\.\\d+|\\d+\\.\\d*)([eE][+-]?\\d+)?\\s*$"); } public static void main(String[] args) { // TODO Auto-generated method stub ValidNumber v = new ValidNumber(); System.out.println(v.isNumber("3.1")); System.out.println(v.isNumber("- 8.9")); System.out.println(v.isNumber("2.")); System.out.println(v.isNumber("abc")); System.out.println(v.isNumber("e10")); System.out.println(v.isNumber("5e10")); } }
原文：http://www.cnblogs.com/shuaiwhu/p/5087614.html