一个判断字数类型的类

public class JMath {

   /**
     * support Numeric format:<br>
     * "33" "+33" "033.30" "-.33" ".33" " 33." " 000.000 " 2e4 0.36e-4
     * @param str String
     * @return boolean
     */
   public static boolean isNumeric(String str) {
       int begin = 0;
       boolean once = true;
       boolean once2 = true;
       if (str == null || str.trim().equals("")) {
           return false;
       }
       str = str.trim();
       if (str.startsWith("+") || str.startsWith("-")) {
           if (str.length() == 1) {
               // "+" "-"
               return false;
           }
           begin = 1;
       }
       for (int i = begin; i < str.length(); i++) {
           if (!Character.isDigit(str.charAt(i))) {
               if (str.charAt(i) == '.' && once) {
                   // '.' can only once
                   once = false;
               }else if(String.valueOf(str.charAt(i)).toLowerCase().equals("e") && once2 && i>begin && i<str.length()-1)
               {
                once2=false;
               }
               else {
                   return false;
               }
           }
       }
       if (str.length() == (begin + 1) && !once) {
           // "." "+." "-."
           return false;
       }
       return true;
   }

   /**
     * support Integer format:<br>
     * "33" "003300" "+33" " -0000 "
     * @param str String
     * @return boolean
     */
   public static boolean isInteger(String str) {
       int begin = 0;
       if (str == null || str.trim().equals("")) {
           return false;
       }
       str = str.trim();
       if (str.startsWith("+") || str.startsWith("-")) {
           if (str.length() == 1) {
               // "+" "-"
               return false;
           }
           begin = 1;
       }
       for (int i = begin; i < str.length(); i++) {
           if (!Character.isDigit(str.charAt(i))) {
               return false;
           }
       }
       return true;
   }

   /**
     * use Exception
     * support Numeric format:<br>
     * "33" "+33" "033.30" "-.33" ".33" " 33." " 000.000 "
     * @param str String
     * @return boolean
     */
   public static boolean isNumericEx(String str) {
       try {
           Double.parseDouble(str);
           return true;
       }
       catch (NumberFormatException ex) {
           return false;
       }
   }

   /**
     * use Exception
     * support less than 11 digits(<11)<br>
     * support Integer format:<br>
     * "33" "003300" "+33" " -0000 " "+ 000"
     * @param str String
     * @return boolean
     */
   public static boolean isIntegerEx(String str) {
       str = str.trim();
       try {
           Integer.parseInt(str);
           return true;
       }
       catch (NumberFormatException ex) {
           if (str.startsWith("+")) {
               return isIntegerEx(str.substring(1));
           }
           return false;
       }
   }

   /**
    * using Regular Expression
    *
    * support Integer format:<br>
    * "33" "003300" " -0000 "
    *
    * Date: Jul 30, 2008
    *
    * @param str
    * @return
    */
   public static boolean isIntegerRegex(String str) { 
 
     Pattern pattern = Pattern.compile("^[+\\-]?\\d+$");
     Matcher matcher = pattern.matcher(str.trim());
     return matcher.matches();
   }

   /**
    * using Regular Expression
    *
    * support Numeric format:<br>
    * "33" "+33" "033.30" "-.33" ".33" " 000.000 "
    * @param str String
    * @return boolean
    */
   public static boolean isNumericRegex(String str) {

     Pattern pattern = Pattern.compile("^[+\\-]?((\\d*\\.\\d+)|(\\d+))$");
     Matcher matcher = pattern.matcher(str.trim());
     return matcher.matches();
   }

 }