常用正则

//检测用户名合法性
public void checkUserName() {
    String regex = "([a-z]|[A-Z]|[\\u4e00-\\u9fa5])+";
    Pattern p = Pattern.compile(regex);
    Matcher m = p.matcher("张三");
    System.out.println("checkUserName : "+m.matches());
}

//检测15或18位身份证  15位是第一代身份证，18位是第二代身份证，末位可能是x
public void checkIdCard15Or18() {
    String regex = "(^\\d{18}$)|(^\\d{15}$)|(^\\d{17}(\\d|X|x)$)";
    Pattern p = Pattern.compile(regex);
    Matcher m = p.matcher("11222111222122122X");
    System.out.println("checkIdCard : "+m.matches());
}

//检测是否是数字
public void checkIsNumber() {
    String regex = "(^-?[1-9]\\d*$)|(^-?([1-9]\\d*\\.\\d*|0\\.\\d*[1-9]\\d*|0?\\.0+|0)$)";
    Pattern p = Pattern.compile(regex);
    Matcher m = p.matcher("1234.21");
    System.out.println("checkIsNumber : "+m.matches());
}