数字正则表达式

import java.util.regex.Pattern
      import java.util.regex.Matcher

        public boolean isNumeric(String str)
      {
            Pattern pattern = Pattern.compile("[0-9]*");
            Matcher isNum = pattern.matcher(str);
            if( !isNum.matches() )
            {
                  return false;
            }
            return true;
      }