The Alphanumericals are a combination of alphabetical [a-zA-Z] and numerical [0-9] characters, a total of 62 characters, and we can use regex [a-zA-Z0-9]+ to matches alphanumeric characters. If we want regex matches non-alphanumeric characters, prefix it with a negate symbol ^, meaning we want any characters that are not alphanumeric. ^[^a-zA-Z0-9]+$ Regex explanation ^ # […]
The Alphanumericals are a combination of alphabetical [a-zA-Z] and numerical [0-9] characters, 62 characters. We can use below regex to match alphanumeric characters: ^[a-zA-Z0-9]+$ Regex explanation ^ # start string [a-z] # lowercase letters from a to z [A-Z] # uppercase letters from A to Z [0-9] # digits from 0 to 9 + # […]
This article shows how to use regex + code to validate a date format, support single and leading zero month and day format (1 or 01), check for the 30 or 31 days of the month, and leap year validation. Below are the requirements for a valid date. Year format, 1900, 2099 regex Month format, […]
This article focus on how to validate an IP address (IPv4) using regex and Apache Commons Validator. Here is the summary. IPv4 regex explanation. Java IPv4 validator, using regex. Java IPv4 validator, using commons-validator-1.7 JUnit 5 unit tests for the above IPv4 validators. IPv4 regex final version. ^(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\.(?!$)|$)){4}$ # Explanation ( [0-9] # 0-9 | […]
This article shows how to use regex to validate a username in Java. Username requirements Username consists of alphanumeric characters (a-zA-Z0-9), lowercase, or uppercase. Username allowed of the dot (.), underscore (_), and hyphen (-). The dot (.), underscore (_), or hyphen (-) must not be the first or last character. The dot (.), underscore […]
This article shows how to use regex to validate a password in Java. Secure Password requirements Password must contain at least one digit [0-9]. Password must contain at least one lowercase Latin character [a-z]. Password must contain at least one uppercase Latin character [A-Z]. Password must contain at least one special character like ! @ […]
The format of an email address is local-part@domain. Look at this email address [email protected] local-part = mkyong @ = @ domain = example.com The formal definitions of an email address are in RFC 5322 and RFC 3696. However, this article will not follow the above RFC for email validation. The official email "local-part" is too […]
This article shows how to use regex to validate a hex color code. Regex for hex color code. ^#([a-fA-F0-9]{6}|[a-fA-F0-9]{3})$ Regex explanation ^ # start of the line # # start with a number sign `#` ( # start of (group 1) [a-fA-F0-9]{6} # support z-f, A-F and 0-9, with a length of 6 | # […]
This article shows how to use regex to remove spaces in between a String. A string with spaces in between. String text = "Hello World Java."; We want to remove the spaces and display it as below: Hello World Java. 1. Java regex remove spaces In Java, we can use regex \\s+ to match whitespace […]
