public static void main(String args[]) {
Pattern pattern = Pattern.compile("^[-+]?(([0-9]+)([.]([0-9]+))?|([.]([0-9]+))?)$");
Matcher isNum = pattern.matcher("1");
if (!isNum.matches()) {
System.out.println("不是数字");
}else{
System.out.println("是数字");
}
}