Spring MVC Annotation (JSR-303) Bean Validation With @Valid Example

Validating a (spring) bean is a mandatory thing in every IT individual project, let us see how to validate a bean in spring MVC JSR-303.  Please check this tutorial before you read this article [ https://www.java4s.com/spring-mvc/spring-mvc-annotation-jsr-303-validation-tutorial/ ].  In order to work with JSR-303 you should have validation-api-1.0.0.GA.jar,hibernate-validator-4.2.0.Final.jar in your class path. You can download these files from maven repository, dont confuse hibernate-validator-4.2.0.Final.jar is a reference implementation for JSR-303 :-).  However i provided the download links for the above jar files in the previous article.

You can do validations upto some extent with a single jar file, either validation-api-1.0.0.GA.jar or hibernate-validator-4.2.0.Final.jar  but with combination we can do better validations 🙂

Files Required

• index.jsp
• web.xml
• Java4sController.java
• java4s-servlet.xml
• loginPage.jsp
• UserDetails.java
• success.jsp
• failure.jsp
• props.properties

Directory Structure

index.jsp

<font face="verdana" size="2">
   <a href="displayForm.html">Login..</a>
</font>

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/j2ee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" id="WebApp_ID" version="2.4">
<servlet>
   <servlet-name>java4s</servlet-name>
   <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
   <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
   <servlet-name>java4s</servlet-name>
   <url-pattern>/</url-pattern>
</servlet-mapping>

<welcome-file-list>
   <welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

Java4sController.java

package java4s;

import javax.validation.Valid;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class Java4sController {    

        @RequestMapping(value="displayForm", method=RequestMethod.GET)
        public String helloWorld(UserDetails ud) {
            return "loginPage";            
        }

        @RequestMapping("/login")
        public String loginCheck(@Valid UserDetails userDetails, BindingResult result, ModelMap model) {
            if (result.hasErrors()) {
                return "loginPage";
            } else {
                model.addAttribute("lfobj", userDetails);
                return "success";
            }
        }

}

java4s-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:p="http://www.springframework.org/schema/p"
    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-3.2.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">

<context:component-scan base-package="java4s" />

    <mvc:annotation-driven />

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>

    <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
       <property name="basename" value="props" />
    </bean>

</beans>

loginPage.jsp

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>

<html>
<head>
     <title>Spring3Example</title>
<style>
  .error {
      color: #EF1313;
      font-style: italic;
  }
</style>
</head>
<body>

<form:form action="login.html" commandName="userDetails">
<table>
<tr>
    <td><font face="verdana" size="2px">User</font></td>
    <td>:</td>
    <td>
    <font face="verdana" size="2">
    <form:input path="user" /> <form:errors path="user"></form:errors>
    </font>
    </td>
</tr>
<tr>
    <td><font face="verdana" size="2px">Email</font></td>
    <td>:</td>
    <td>
    <font face="verdana" size="2">
    <form:input path="email" /> <form:errors path="email"></form:errors>
    </font>
    </td>
</tr>
<tr>
    <td><font face="verdana" size="2px">Phone</font></td>
    <td>:</td>
    <td>
    <font face="verdana" size="2">
    <form:input path="phone" /> <form:errors path="phone"></form:errors>
    </font>
    </td>
</tr>
<tr>
    <td><font face="verdana" size="2px">Blog</font></td>
    <td>:</td>
    <td>
    <font face="verdana" size="2">
    <form:input path="blog" /> <form:errors path="blog"></form:errors>
    </font>
    </td>
</tr>
<tr>
    <td>
    <input type="submit" value="Submit" />
    </td>
</tr>
</table>
</form:form>
</body>
</html>

UserDetails.java

package java4s;

import javax.validation.constraints.Size;

import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.NotEmpty;
import org.hibernate.validator.constraints.URL;

public class UserDetails{

        @NotEmpty
        private String user;

        @NotEmpty
        @Email
        private String email;        

        @NotEmpty(message = "Phone should not be blank.")
        @Size(min = 10,max = 10)
        private String phone;

        @NotEmpty(message = "Enter your blog URL")
        @URL
        private String blog;

        public String getUser() {
            return user;
        }

        public void setUser(String user) {
            this.user = user;
        }

        public String getEmail() {
            return email;
        }

        public void setEmail(String email) {
            this.email = email;
        }

        public String getPhone() {
            return phone;
        }

        public void setPhone(String phone) {
            this.phone = phone;
        }

        public String getBlog() {
            return blog;
        }

        public void setBlog(String blog) {
            this.blog = blog;
        }

}

success.jsp

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<html>
<head>
<style>
       table td{font-family:verdana;font-size: 12px;}
</style>
</head>

<body>
<font face="verdana" size="2">Welcome Mr. <b>${lfobj.user}</b>,<br>
Validations Success..!<br><br>
<u>You Entered</u><br>
</font>

<table>
    <tr><td>Email</td><td>${lfobj.email}</td></tr>
    <tr><td>Phone</td><td>${lfobj.phone}</td></tr>
    <tr><td>Website</td><td>${lfobj.blog}</td></tr>
</table>
</body>
</html>

failure.jsp

<html>
<font face="verdana" size="2">
<b>Login Failed..!</b><br>
    Please enter 'java4s' as user name and 'pass' as password.
</font>
</html>

props.properties

NotEmpty.userDetails.user = User Name is required
NotEmpty.userDetails.email = Email is required

Email.userDetails.email = Enter valid email Id
URL.userDetails.blog = Enter valid URL

Explanation

• Run the application > index.jsp file will be executed
• I am calling displayForm.html from index.jsp, so DispatcherServlet passes the request to Java4sController.java
• In Java4sController line number 14, mapping will be verified, and helloWorld(UserDetails ud) method will be executed and it will return string value ‘loginPage‘ from that method, in other words loginPage.jsp page will be executed
• So loginPage.jsp > line number 15, once we click on submit button ‘login.html’ action will be called
• Again come to Java4sController.java line number  19, mapping will be verified, and flow moves to loginCheck(@valid -,-,-) method, there in the first parameter i am using @Valid annotation, and calling the bean as @Valid UserDetails userDetails
• Now come to UserDetails.java > validations will be executed > if have any errors container adds those errors to BindingResult object [2nd parameter of loginCheck(-,-,-) method of Java4sController class ]
• Finally check the error(s) and open either success or failure page, that’s it

Notes:

1. In Java4sController line number 15, is it necessary to take our bean class as parameter in helloWorld(UserDetails ud) ?
A] Yes we should, the reason being before we call loginPage.jsp [in line number 16 of Java4sController] we need to set the fields to their default or empty in the jsp before it loads, so i am taking UserDetails bean as parameter, so just wait….!!!! check loginPage.jsp line number 15, i have written commandName=”userDetails“,

Did you observe…?

My Bean name is UserDetails
and i took commandName in loginPage.jsp [line number 15] as userDetails

In jsp, i have taken commandName value same as my bean name but first character is lower 🙂 which is default notation while creating object in java.  So when ever we call loginPage.jsp, fields will automatically get mapped[assigned to empty or null], hope you understood my pain ;), this is very important step, there might be a chance of getting Run time exception if we ignore this step.

2. Can we write helloWorld(UserDetails ud) method of Java4sController without passing UserDetails object ?
A] Of course we can 🙂
We can change helloWorld(-) method….

@RequestMapping(value="displayForm", method=RequestMethod.GET)
        public String helloWorld(UserDetails ud) {
            return "loginPage";            
}

to

@RequestMapping(value="displayForm", method=RequestMethod.GET)
         public String helloWorld(ModelMap model) {
      UserDetails ud = new UserDetails();
       ud.setUser("");
       ud.setPass("");
      model.addAttribute("userDetails",ud);
      return "loginPage";            
}

But make sure, key in model.addAttribute(“userDetails“,ud) should match with commandName=”userDetails” in jsp, that’s it.

Output

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• Spring MVC Annotation (JSR-303) Validation Tutorial
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::. About the Author .::
		Sivateja Kandula - Java/J2EE Full Stack Developer Founder of Java4s - Get It Yourself, A popular Java/J2EE Programming Blog, Love Java and UI frameworks. You can sign-up for the Email Newsletter for your daily dose of Java tutorials.