Following example shows how to use Spring native validation (check out related core tutorial) in a MVC application. We need to implement Validator interface and perform validation programmatically. This is an alternative to JSR 349/303 annotation based validations (last example).
Example
A Java Bean
public class User {
private Long id;
private String name;
private String password;
private String emailAddress;
.............
}
Implementing Validator
package com.logicbig.example;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
import java.util.regex.Pattern;
public class UserValidator implements Validator {
private static final Pattern EMAIL_REGEX =
Pattern.compile("^[\\w\\d._-]+@[\\w\\d.-]+\\.[\\w\\d]{2,6}$");
@Override
public boolean supports(Class<?> clazz) {
return clazz == User.class;
}
@Override
public void validate(Object target, Errors errors) {
ValidationUtils.rejectIfEmpty(errors, "name", "user.name.empty");
ValidationUtils.rejectIfEmpty(errors, "password", "user.password.empty");
ValidationUtils.rejectIfEmpty(errors, "emailAddress", "user.email.empty");
User user = (User) target;
if (user.getName() != null && user.getName().length() < 5 ||
user.getName().length() > 20) {
errors.rejectValue("name", "user.name.size");
}
if (user.getPassword() != null && user.getPassword().contains(" ")) {
errors.rejectValue("password", "user.password.space");
}
if (user.getPassword() != null && user.getPassword().length() < 5 &&
user.getPassword().length() > 15) {
errors.rejectValue("password", "user.password.size");
}
if (user.getEmailAddress() != null && !EMAIL_REGEX.matcher(user.getEmailAddress()).matches()) {
errors.rejectValue("emailAddress", "user.email.invalid");
}
}
}
Message Source
src/main/resources/ValidationMessages_en.propertiesuser.name.empty=User Name cannot be empty.
user.name.size=User Name must be of more than 5 and less than 20 characters.
user.password.empty=User Password cannot be empty.
user.password.size=User Password length must of between 6 and 15.
user.password.space=Password must not have spaces.
user.email.empty=User Email cannot be empty.
user.email.invalid=Email is not valid.
Spring Controller
@Controller
@RequestMapping("/register")
public class UserRegistrationController {
@Autowired
private UserService userService;
@RequestMapping(method = RequestMethod.GET)
public String handleGetRequest (Model model) {
model.addAttribute("user", new User());
return "user-registration";
}
@RequestMapping(method = RequestMethod.POST)
public String handlePostRequest (@ModelAttribute("user") User user,
BindingResult bindingResult, Model model) {
new UserValidator().validate(user, bindingResult);
if (bindingResult.hasErrors()) {
return "user-registration";
}
userService.saveUser(user);
return "registration-done";
}
}
JSP Form
src/main/webapp/WEB-INF/views/user-registration.jsp<%@taglib uri="http://www.springframework.org/tags/form" prefix="frm"%>
<html>
<head>
<style>
span.error {
color: red;
display: inline-block;
}
</style>
</head>
<body>
<h3> Registration Form <h3>
<br/>
<frm:form action="register" method="post" commandName="user">
<pre>
Name <frm:input path="name" />
<frm:errors path="name" cssClass="error" />
Email address <frm:input path="emailAddress" />
<frm:errors path="emailAddress" cssClass="error" />
Password <frm:password path="password" />
<frm:errors path="password" cssClass="error" />
<input type="submit" value="Submit" />
</pre>
</frm:form>
</body>
</html>
Java Config
@EnableWebMvc
@Configuration
public class MyWebConfig {
@Bean
public MessageSource messageSource() {
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
messageSource.setBasenames("ValidationMessages");
return messageSource;
}
@Bean
public UserRegistrationController userRegistrationController() {
return new UserRegistrationController();
}
@Bean
public UserService userService() {
return new InMemoryUserService();
}
@Bean
public ViewResolver viewResolver () {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/views/");
viewResolver.setSuffix(".jsp");
return viewResolver;
}
}
To try examples, run embedded tomcat (configured in pom.xml of example project below):
mvn tomcat7:run-war Output
Submitting invalid values:
Example ProjectDependencies and Technologies Used: - spring-webmvc 4.2.4.RELEASE: Spring Web MVC.
- spring-test 4.2.4.RELEASE: Spring TestContext Framework.
- javax.servlet-api 3.0.1 Java Servlet API
- junit 4.12: JUnit is a unit testing framework for Java, created by Erich Gamma and Kent Beck.
- JDK 1.8
- Maven 3.3.9
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