Programming for beginners: Spring web mvc: Bind Date type

In this post, I am going to show you how to bind Date type to java model object. If Date is with the format ‘yyyy/mm/dd’, then spring automatically binds the request parameter to java Date object.

In this post, you are going to learn below things.

a. How to bind the Date of format ‘yyyy/mm/dd’

b. How to bind the Date of different format.

How to bind the Date of format ‘yyyy/mm/dd’

I am going to develop a student registration form. Student must provide below information to register himself.

Information	Type
userName	String
age	int
hobbies	Collection
dateOfBirth	java.util.Date

public class Student {

private String userName;

private int age;

private List<String> hobbies;

private Date dateOfBirth;

.....

}

There is nothing special about date mapping. Use the @ModelAttribute annotation on method argument of Student object, spring takes care of data binding for you.

@RequestMapping("/registerMe")

public ModelAndView getHelloMessage(@ModelAttribute("studentInfo") Student student, BindingResult bindingResult) {

.....

}

Find the below working application.

HelloWorldController.java

package com.sample.myApp.controllers;

import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

import com.sample.myApp.model.Student;

@Controller
public class HelloWorldController {

 @RequestMapping("/registration")
 public String getRegistrationpage() {
  return "registration";
 }

 @RequestMapping("/registerMe")
 public ModelAndView getHelloMessage(@ModelAttribute("studentInfo") Student student, BindingResult bindingResult) {
  if (bindingResult.hasErrors()) {
   ModelAndView modelAndView = new ModelAndView("registration");
   return modelAndView;
  }

  ModelAndView modelAndView = new ModelAndView("welcome");

  modelAndView.addObject("message", "Dear User, your details are registered");

  return modelAndView;
 }

}

Student.java

package com.sample.myApp.model;

import java.util.Date;
import java.util.List;

public class Student {
 private String userName;
 private int age;
 private List<String> hobbies;
 private Date dateOfBirth;

 public Date getDateOfBirth() {
  return dateOfBirth;
 }

 public void setDateOfBirth(Date dateOfBirth) {
  this.dateOfBirth = dateOfBirth;
 }

 public String getUserName() {
  return userName;
 }

 public void setUserName(String userName) {
  this.userName = userName;
 }

 public int getAge() {
  return age;
 }

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

 public List<String> getHobbies() {
  return hobbies;
 }

 public void setHobbies(List<String> hobbies) {
  this.hobbies = hobbies;
 }

}

Create registration.jsp, hello.jsp files under WEB-INF/jsp folder.

registration.jsp

<%@taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<html>
<head>
<title>User Information Page</title>
</head>

<body>
 <h2 style="color:red;"><form:errors path="studentInfo.*" /></h2>

 <form method="post" action="/springdemo/registerMe" id="f1">
  <table>
   <tr>
    <td>User Name :</td>
    <td><input type="text" name="userName" value="" /></td>
   </tr>
   <tr>
    <td>Age :</td>
    <td><input type="text" name="age" value="" /></td>
   </tr>
   <tr>
    <td>Hobbies :</td>
    <td><select multiple name="hobbies">
      <option value="cricket">Cricket</option>
      <option value="chess">Chess</option>
      <option value="football">Football</option>
      <option value="tennis">Tennis</option>
    </select></td>
   </tr>
   
   <tr>
    <td>Date Of Birth</td>
    <td><input type="text" name="dateOfBirth" value="" /></td>
   </tr>
   <tr>
    <td><input type="submit" name="submit" value="submit"
     style="font-size: 18px;" /></td>
   </tr>
  </table>
 </form>

</body>
</html>

welcome.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
 pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Hello World Spring Web MVC</title>
</head>
<body>
 <h1>${message}</h1>

 <h3>
  User Name : ${studentInfo.userName} <br /> 
  Age : ${studentInfo.age} <br />
  Hobbies: ${studentInfo.hobbies} <br />
  Date Of Birth: ${studentInfo.dateOfBirth}
 </h3>
</body>
</html>

Create web.xml, HelloWorld-servlet.xml files under WEB-INF folder.

web.xml

<web-app id="WebApp_ID" version="2.4"
 xmlns="http://java.sun.com/xml/ns/j2ee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
   http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

 <display-name>Spring MVC Hello WorldApplication</display-name>

 <servlet>
  <servlet-name>HelloWorld</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <load-on-startup>1</load-on-startup>
 </servlet>

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

</web-app>

HelloWorld-servlet.xml

<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:context="http://www.springframework.org/schema/context"
 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
   http://www.springframework.org/schema/context 
   http://www.springframework.org/schema/context/spring-context-3.0.xsd">

 <context:component-scan
  base-package="com.sample.myApp" />

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

</beans>

Create index.jsp file under webapp folder.

index.jsp

<%@taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<html>
<head>
<title>Welcome Page</title>
</head>

<body>
 <h3>Dear Student, click on below button to register yourself</h3>
 <form method="post" action="/springdemo/registration" id="f1">
  <input type="submit" name="submit" value="submit"
   style="font-size: 18px;" />
 </form>
</body>
</html>

Project structure looks like below.

Run the application on server. You can able to get below kind of screen.

Click on submit button, it navigates you to the registration page.

Fill the registration form, fill the date in ‘YYYY/MM/DD’ format. Click on submit button.

You can able to see successful message like below.

Now go back to the registration page again and enter the date in ‘YYYY@@MM@@DD’ format.

Click on submit button, you can able to see below kind of data bind error.

It is because, spring doesn’t know how to bind the string of format ‘YYYY@@MM@@DD’ to date type.

How to bind the Date of different format?

By using custom property editors, we can customize the data binding process.

For example, below method customize the date format. I am using spring CustomDateEditor class to support custom date format.

@InitBinder

public void customizeBinding(WebDataBinder dataBinder) {

SimpleDateFormat dateFormat = new SimpleDateFormat("YYYY@@MM@@DD");

dataBinder.registerCustomEditor(Date.class, "dateOfBirth", new CustomDateEditor(dateFormat, false));

}

Update HelloWorldController class like below.

HelloWorldController.java

package com.sample.myApp.controllers;

import java.sql.Date;
import java.text.SimpleDateFormat;

import org.springframework.beans.propertyeditors.CustomDateEditor;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

import com.sample.myApp.model.Student;

@Controller
public class HelloWorldController {

 @InitBinder
 public void customizeBinding(WebDataBinder dataBinder) {
  SimpleDateFormat dateFormat = new SimpleDateFormat("YYYY@@MM@@DD");
  dataBinder.registerCustomEditor(Date.class, "dateOfBirth", new CustomDateEditor(dateFormat, false));
 }

 @RequestMapping("/registration")
 public String getRegistrationpage() {
  return "registration";
 }

 @RequestMapping("/registerMe")
 public ModelAndView getHelloMessage(@ModelAttribute("studentInfo") Student student, BindingResult bindingResult) {
  if (bindingResult.hasErrors()) {
   ModelAndView modelAndView = new ModelAndView("registration");
   return modelAndView;
  }

  ModelAndView modelAndView = new ModelAndView("welcome");

  modelAndView.addObject("message", "Dear User, your details are registered");

  return modelAndView;
 }

}

Re deploy the application on server. Now enter the date in ‘YYYY@@MM@@DD’ format.

Click on submit button. You can able to see successful message.

In my next post, I am going to explain about property editors.

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Sunday, 25 November 2018

Spring web mvc: Bind Date type

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