Spring EL regular expression example

Spring EL supports regular expression using a simple keyword “matches“, which is really awesome! For examples,

	@Value("#{'100' matches '\\d+' }")
	private boolean isDigit;

It test whether ‘100‘ is a valid digit via regular expression ‘\\d+‘.

Spring EL in Annotation

See following Spring EL regular expression examples, some mixed with ternary operator, which makes Spring EL pretty flexible and powerful.

Below example should be self-explanatory.

package com.mkyong.core;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("customerBean")
public class Customer {

	// email regular expression
	String emailRegEx = "^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)" +
			"*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";

	// if this is a digit?
	@Value("#{'100' matches '\\d+' }")
	private boolean validDigit;

	// if this is a digit + ternary operator
	@Value("#{ ('100' matches '\\d+') == true ? " +
			"'yes this is digit' : 'No this is not a digit'  }")
	private String msg;

	// if this emailBean.emailAddress contains a valid email address?
	@Value("#{emailBean.emailAddress matches customerBean.emailRegEx}")
	private boolean validEmail;

	//getter and setter methods, and constructor
}

package com.mkyong.core;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("emailBean")
public class Email {

	@Value("[e-mail]")
	String emailAddress;

	//...
}

Output

Customer [isDigit=true, msg=yes this is digit, isValidEmail=true]

Spring EL in XML

See equivalent version in bean definition XML file.

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

	<bean id="customerBean" class="com.mkyong.core.Customer">
	  <property name="validDigit" value="#{'100' matches '\d+' }" />
	  <property name="msg"
		value="#{ ('100' matches '\d+') == true ? 'yes this is digit' : 'No this is not a digit'  }" />
	  <property name="validEmail"
		value="#{emailBean.emailAddress matches '^[_A-Za-z0-9-]+(\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\.[A-Za-z0-9]+)*(\.[A-Za-z]{2,})$' }" />
	</bean>

	<bean id="emailBean" class="com.mkyong.core.Email">
	  <property name="emailAddress" value="[e-mail]" />
	</bean>

</beans>