In this example, we will learn how to create a dropdown box in Spring MVC using Springs tag library. We will use the <form:select> and <form:options> for creating a drop-down. Here we will create a simple Spring MVC form with a country dropdown and we will add validation support to check if it is not empty.
In Spring MVC we will use <form:select> and <form:options> tag to render a dropdown
<form:select path="country">
<form:option value="" label="...." />
<form:options items="${countryList}"/>
</form:select>
Which produces the below HTML code.
<select id="country" name="country">
<option value="">....</option>
<option value="India">India</option>
<option value="Australia">Australia</option>
<option value="England">England</option>
</select>
Folder Structure :
- Create a Dynamic Web Project SpringMVCFormHandling and create a package for our src files “com.javainterviewpoint“
- Place the Spring 3 jar files under WEB-INF/Lib
commons-logging-1.1.1.jar
log4j-1.2.16.jar
slf4j-api-1.7.5.jar
slf4j-log4j12-1.7.5.jar
hibernate-validator-4.2.0.Final.jar
spring-aspects-3.2.4.RELEASE.jar
spring-beans-3.2.4.RELEASE.jar
spring-context-3.2.4.RELEASE.jar
spring-core-3.2.4.RELEASE.jar
spring-expression-3.2.4.RELEASE.jar
spring-web-3.2.4.RELEASE.jar
spring-webmvc-3.2.4.RELEASE.jar
validation-api-1.1.0.Final.jar
jstl-1.1.2.jar - Create the Java classes MVC_Controller.java and RegistrationBean.java under com.javainterviewpoint folder.
- Place the SpringConfig-servlet.xml and web.xml under the WEB-INF directory
- View files SpringMVC_DropDownExample.jsp and dropdown_Success.jsp are put under the sub directory under WEB-INF/Jsp
Controller
Dropdown_Controller.java
- The DispatcherServlet mapping which we make in the web.xml will delegate the all the request to our Dropdown_Controller as we have annotated it with @Controller annotation.
- We use the @RequestMapping annotation to map each of the requests which we get to individual methods. Our controller has three methods getCountry(),initializeForm() and processForm().
- The getCountry() method returns a list of country which will be used by view for populating the country dropdown.
- The initializeForm() will take the user to the “SpringMVC_DropdownExample” which is our view component with form backing object DropdownBean.
- The processForm() method will get called when the user submits the form. The DropdownBean object “db” will be validated as we have annotated it with @Valid annotation and the validation results will be added to the BindingResult. Based on the result we will re-direct the user back to the “SpringMVC_DropdownExample” or “dropdown_Success” page.
package com.javainterviewpoint;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.validation.Valid;
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;
@Controller
public class Dropdown_Controller
{
ModelAndView mav = null;
@ModelAttribute("countryList")
public List getCountry()
{
List countryList = new ArrayList();
countryList.add("India");
countryList.add("Australia");
countryList.add("England");
return countryList;
}
@RequestMapping("/DropdownExample")
public String dispForm(Map model)
{
DropdownBean db = new DropdownBean();
model.put("db",db);
return "SpringMVC_DropdownExample";
}
@RequestMapping("/processCountry")
public String processForm(@Valid @ModelAttribute("db") DropdownBean db1,BindingResult result)
{
if(result.hasErrors())
{
System.out.println("Validation Failed");
return "SpringMVC_DropdownExample";
}
else
{
System.out.println("Validated Successfully");
return "dropdown_Success";
}
}
}
Model
DropdownBean.java
Here DropdownBean act as a Model which has a country property. We have added the annotation @NotEmpty to validate if the user has selected a value in the dropdown. The custom validation messages are added in the props.properties file.
package com.javainterviewpoint;
import org.hibernate.validator.constraints.NotEmpty;
public class DropdownBean
{
@NotEmpty
String country;
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
}
View
SpringMVC_DropdownExample.jsp
Our view component has a dropdown field generated using the Spring form tag library. The dropdown gets its value from our controller class. @ModelAttribute(“countryList”) of our controller will be called and it will return a list of Country when <form:options items=”${countryList}”/> is called.<form:errors> tag displays the error message which occurs during the validation
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
<!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>Insert title here</title>
<style>
.error {
color: #ff0000;
}
.commonerrorblock {
color: #000;
background-color: #ffEEEE;
border: 3px solid #ff0000;
}
</style>
</head>
<body>
<form:form method="post" action="processCountry" commandName="db">
<form:errors path="*" element="div" cssClass="commonerrorblock"/>
<table>
<tr>
<td>Country</td>
<td>
<form:select path="country">
<form:option value="" label="...." />
<form:options items="${countryList}"/>
</form:select>
</td>
<td>
<form:errors path="country" cssClass="error"/>
</td>
</tr>
<tr>
<td></td><td><input type="submit"></td>
</tr>
</table>
</form:form>
</body>
</html>
props.properties
NotEmpty.db.country = Please select a Country!!
dropdown_Success.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>Insert title here</title>
</head>
<body>
Country Selected : ${db.country}
</body>
</html>
Configurations
web.xml
The web.xml has everything about the application that a server needs to know, which is placed under the WEB-INF directory. <servlet-name> contains the name of the SpringConfiguration, when the DispatcherServlet is initialized the framework will try to load a configuration file “[servlet-name]-servlet.xml” under the WEB-INF directory.
<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>SpringMVCFormHandling</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>SpringConfig</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>SpringConfig</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
SpringConfig-servlet.xml
- The SpringConfig-servlet.xml is also placed under the WEB-INF directory.
- <context:component-scan> will let the Spring Container to search for all the annotation under the package “com.javainteriviewpoint”.
- <mvc:annotation-driven/> annotation will activate the @Controller, @RequestMapping, @Valid etc annotations.
- The view is resolved through “org.springframework.web.servlet.view.InternalResourceViewResolver” which searches for the jsp files under the /WEB-INF/Jsp/ directory.
- Resource Bundle is accessed through the “org.springframework.context.support.ResourceBundleMessageSource” through its property “basename” which has the value “props”, and hence our property file should “props.properties”
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" 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 http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <context:component-scan base-package="com.javainterviewpoint" /> <mvc:annotation-driven /> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/Jsp/" /> <property name="suffix" value=".jsp" /> </bean> <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource"> <property name="basename" value="props"></property> </bean> </beans>
Lets run our application
Now lets run our application, do a clean build and deploy the application in the Server
Hit on the url “http://localhost:8080/SpringMVCFormHandling/DropdownExample”
Submit the form without selecting a value in the dropdown.
Upon successful validation, success page will be returned
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