About Jerome Versrynge
This post provides a simple example of a HTML form validation. It is based on the Spring MVC With Annotations example. The code is available on GitHub in the Spring-MVC-Form-Validation directory.
Data
For this example we will use a bean and JSR303 validation annotations:
public class MyUser { @NotNull @Size(min=1,max=20) private String name; @Min(0) @Max(120) private int age; public MyUser(String name, int age) { this.name = name; this.age = age; } public MyUser() { name = ''; age = 0; } // Setters & Getters} Pages
Our form will contain input elements, but also the possibility to display error messages:
<%@page contentType='text/html' pageEncoding='UTF-8'%><%@ taglib prefix='form' uri='http://www.springframework.org/tags/form' %><!doctype html><html><head> <meta http-equiv='Content-Type' content='text/html; charset=UTF-8'> <title>My User Form!</title></head><body> <form:form method='post' action='myForm' commandName='myUser'> <table> <tr> <td>Name: <font color='red'><form:errors path='name' /></font></td> </tr> <tr> <td><form:input path='name' /></td> </tr> <tr> <td>Age: <font color='red'><form:errors path='age' /></font></td> </tr> <tr> <td><form:input path='age' /></td> </tr> <tr> <td><input type='submit' value='Submit' /></td> </tr> </table> </form:form></body></html>
Our success page is:
<%@page contentType='text/html' pageEncoding='UTF-8'%><%@taglib prefix='form' uri='http://www.springframework.org/tags/form'%><%@ taglib prefix='c' uri='http://java.sun.com/jsp/jstl/core' %><!doctype html><html><head> <meta http-equiv='Content-Type' content='text/html; charset=UTF-8'> <title>Form Processed Successfully!</title></head><body> Form processed for <c:out value='${myUser.name}' /> ! <br /> <a href='<c:url value='/'/>'>Home</a></body></html> Our home page:
<%@page contentType='text/html' pageEncoding='UTF-8'%><%@ taglib prefix='c' uri='http://java.sun.com/jsp/jstl/core' %><!doctype html><html lang='en'><head> <meta charset='utf-8'> <title>Welcome !!!</title></head><body> <h1> Spring Form Validation !!! </h1><a href='<c:url value='/myForm'/>'>Go to the form!</a></body></html>
Controller
Notice that we need to use @ModelAttribute to make sure an instance of MyUser is always available in the model. In the validateForm(), we need to use @ModelAttribute to move the content of the form to the MyUser project.
@Controllerpublic class MyController { @RequestMapping(value = '/') public String home() { return 'index'; } @ModelAttribute('myUser') public MyUser getLoginForm() { return new MyUser(); } @RequestMapping(value = '/myForm', method = RequestMethod.GET) public String showForm(Map model) { return 'myForm'; } @RequestMapping(value = '/myForm', method = RequestMethod.POST) public String validateForm( @ModelAttribute('myUser') @Valid MyUser myUser, BindingResult result, Map model) { if (result.hasErrors()) { return 'myForm'; } model.put('myUser', myUser); return 'success'; }} Maven Dependencies
We need the following dependencies. The Hibernate validator dependency is necessary to process JSR303 annotations:
<dependency> <groupId>javax.validation</groupId> <artifactId>validation-api</artifactId> <version>1.0.0.GA</version> <type>jar</type></dependency><dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-validator</artifactId> <version>4.3.0.Final</version></dependency>
Running The Example
Once compiled, the example can be run with
mvn tomcat:run. Then, browse:
http://localhost:8383//spring-mvc-form-validation/.
If the end user enters invalid values, error messages will be displayed:
Reference: Spring MVC Form Validation (With Annotations) from our JCG partner Jerome Versrynge at the Technical Notes blog.
Source : http://www.javacodegeeks.com/2013/04/spring-mvc-form-validation-with-annotations-2.html
