Android 常用正则表达式

String validateFormat = "[a-zA-Z][a-zA-Z0-9]{5,19}";

public static boolean validatePwd(String password) {
boolean flag = false;
String validateFormat = "[a-zA-Z][a-zA-Z0-9]{5,19}";//验证密码6-20 第一个必须为字母
Pattern pattern = Pattern.compile(validateFormat);
Matcher matcher = pattern.matcher(password);
return matcher.matches();
}