Spring MVC Custom Validation

The Spring MVC framework allows us to perform custom validations. In such case, we declare own annotations. We can perform validation on the basis of own business logic.

Spring MVC Custom Validation Example

In this example, we use both pre-defined annotations as well as custom annotations to validate user input.

1. Add dependencies to pom.xml file.

pom.xml

<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.1.1.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper -->
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-jasper</artifactId>
    <version>9.0.12</version>
</dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>  
    <groupId>javax.servlet</groupId>  
    <artifactId>servlet-api</artifactId>  
    <version>3.0-alpha-1</version>  
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>
 <!-- https://mvnrepository.com/artifact/org.hibernate.validator/hibernate-validator -->
<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.13.Final</version>
</dependency>

2. Create the bean class

Employee.java

package com.javatpoint;

import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import com.javatpoint.customvalidation.Password;

public class Employee {
	private String name;
	//Custom annotation
	@Password
	private String password;
	//Predefined annotation
	@Min(value=18, message="must be equal or greater than 18")
	@Max(value=45, message="must be equal or less than 45")
	private int age;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}	
}

3. Create the controller class

EmployeeController.java

 package com.javatpoint;

import javax.validation.Valid;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class EmployeeController {
	
	@RequestMapping("/hello")
	public String showForm(Model theModel) {
		
		theModel.addAttribute("emp", new Employee());
		
		return "viewpage";
	}
	
	@RequestMapping("/helloagain")
	public String processForm(
			@Valid @ModelAttribute("emp") Employee emp,
			BindingResult br) {
				
		if (br.hasErrors()) {
			return "viewpage";
		}
		else {
			return "final";
		}
	}
}

4. Create the validator annotation

Password.java

package com.javatpoint.customvalidation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import javax.validation.Constraint;
import javax.validation.Payload;

@Constraint(validatedBy = PasswordConstraintValidator.class)
@Target( { ElementType.METHOD, ElementType.FIELD } )
@Retention(RetentionPolicy.RUNTIME)
public @interface Password {
	//error message
		public String message() default "must contain jtp";
	//represents group of constraints	
		public Class<?>[] groups() default {};
	//represents additional information about annotation
		public Class<? extends Payload>[] payload() default {};
}

5. Create the validator class

PasswordConstraintValidator.java

package com.javatpoint.customvalidation;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class PasswordConstraintValidator implements ConstraintValidator<Password,String> {

	public boolean isValid(String s, ConstraintValidatorContext cvc) {
		
		boolean result=s.contains("jtp");
		return result;
	}
}

6. Provide the entry of controller in the web.xml file

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>SpringMVC</display-name>
   <servlet>  
    <servlet-name>spring</servlet-name>  
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  
    <load-on-startup>1</load-on-startup>    
</servlet>  
<servlet-mapping>  
    <servlet-name>spring</servlet-name>  
    <url-pattern>/</url-pattern>  
</servlet-mapping>  
</web-app>

7. Define the bean in the xml file

spring-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="
		http://www.springframework.org/schema/beans
    	http://www.springframework.org/schema/beans/spring-beans.xsd
    	http://www.springframework.org/schema/context
    	http://www.springframework.org/schema/context/spring-context.xsd
    	http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">
	<!-- Provide support for component scanning -->
	<context:component-scan base-package="com.javatpoint" />
	<!--Provide support for conversion, formatting and validation -->
	<mvc:annotation-driven/>
	<!-- Define Spring MVC view resolver -->
     <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"></property>
        <property name="suffix" value=".jsp"></property>     
     </bean>
</beans>

8. Create the requested page

index.jsp

<html>
<body>
<a href="hello">Click here...</a>
</body>
</html>

9. Create the other view components

viewpage.jsp

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<head>
	<style>
		.error {color:red}
	</style>
</head>
<body>
	<form:form action="helloagain" modelAttribute="emp">
		Username: <form:input path="name" />		
		<br><br>
		
		Password (*): <form:password path="password" />
		<form:errors path="password" cssClass="error" />
		<br><br>
		
		Age (*): <form:input path="age" />
		<form:errors path="age" cssClass="error" />
		<br><br>
		<input type="submit" value="Submit" />
	</form:form>
</body>
</html>

final.jsp

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<body>
Username: ${emp.name}<br><br>
Password: ${emp.password}<br><br>
Age: ${emp.age}
<br><br>
</body>
</html>

Output: