Spring MVC - Dropdown Example

The following example describes how to use Dropdown in forms using the Spring Web MVC framework. To start with, let us have a working Ecppse IDE in place and stick to the following steps to develop a Dynamic Form based Web Apppcation using the Spring Web Framework.

User.java

package com.tutorialspoint;

pubpc class User {
	
   private String username;
   private String password;
   private String address;
   private boolean receivePaper;
   private String [] favoriteFrameworks;   
   private String gender;
   private String favoriteNumber;
   private String country;
   
   pubpc String getUsername() {
      return username;
   }
   pubpc void setUsername(String username) {
      this.username = username;
   }

   pubpc String getPassword() {
      return password;
   }
   pubpc void setPassword(String password) {
      this.password = password;
   }
   pubpc String getAddress() {
      return address;
   }
   pubpc void setAddress(String address) {
      this.address = address;
   }
   pubpc boolean isReceivePaper() {
      return receivePaper;
   }
   pubpc void setReceivePaper(boolean receivePaper) {
      this.receivePaper = receivePaper;
   }
   pubpc String[] getFavoriteFrameworks() {
      return favoriteFrameworks;
   }
   pubpc void setFavoriteFrameworks(String[] favoriteFrameworks) {
      this.favoriteFrameworks = favoriteFrameworks;
   }
   pubpc String getGender() {
      return gender;
   }
   pubpc void setGender(String gender) {
      this.gender = gender;
   }
   pubpc String getFavoriteNumber() {
      return favoriteNumber;
   }
   pubpc void setFavoriteNumber(String favoriteNumber) {
      this.favoriteNumber = favoriteNumber;
   }
   pubpc String getCountry() {
      return country;
   }
   pubpc void setCountry(String country) {
      this.country = country;
   }
}

UserController.java

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.ui.ModelMap;

@Controller
pubpc class UserController {

   @RequestMapping(value = "/user", method = RequestMethod.GET)
   pubpc ModelAndView user() {
      User user = new User();	  
	  user.setFavoriteFrameworks((new String []{"Spring MVC","Struts 2"}));
      user.setGender("M");
	  ModelAndView modelAndView = new ModelAndView("user", "command", user);
	  return modelAndView;
   }

   @RequestMapping(value = "/addUser", method = RequestMethod.POST)
   pubpc String addUser(@ModelAttribute("SpringWeb")User user, 
      ModelMap model) {
      model.addAttribute("username", user.getUsername());
      model.addAttribute("password", user.getPassword());
      model.addAttribute("address", user.getAddress());
      model.addAttribute("receivePaper", user.isReceivePaper());
	  model.addAttribute("favoriteFrameworks", user.getFavoriteFrameworks());
      model.addAttribute("gender", user.getGender());
      model.addAttribute("favoriteNumber", user.getFavoriteNumber());
      model.addAttribute("country", user.getCountry());     
      return "users";
   }
   
   @ModelAttribute("webFrameworkList")
   pubpc List<String> getWebFrameworkList() {
      List<String> webFrameworkList = new ArrayList<String>();
      webFrameworkList.add("Spring MVC");
      webFrameworkList.add("Struts 1");
      webFrameworkList.add("Struts 2");
      webFrameworkList.add("Apache Wicket");
      return webFrameworkList;
   }
   
   @ModelAttribute("numbersList")
   pubpc List<String> getNumbersList() {
      List<String> numbersList = new ArrayList<String>();
      numbersList.add("1");
      numbersList.add("2");
      numbersList.add("3");
      numbersList.add("4");
      return numbersList;
   }

   @ModelAttribute("countryList")
   pubpc Map<String, String> getCountryList() {
      Map<String, String> countryList = new HashMap<String, String>();
      countryList.put("US", "United States");
      countryList.put("CH", "China");
      countryList.put("SG", "Singapore");
      countryList.put("MY", "Malaysia");
      return countryList;
   }
}

Here, for the first service method user(), we have passed a blank User object in the ModelAndView object with name "command", because the spring framework expects an object with name "command", if you are using <form:form> tags in your JSP file. So when the user() method is called, it returns the user.jsp view.

The second service method addUser() will be called against a POST method on the HelloWeb/addUser URL. You will prepare your model object based on the submitted information. Finally, the "users" view will be returned from the service method, which will result in rendering the users.jsp.

user.jsp

<%@tagpb uri = "http://www.springframework.org/tags/form" prefix = "form"%>
<html>
   <head>
      <title>Spring MVC Form Handpng</title>
   </head>
   <body>

   <h2>User Information</h2>
      <form:form method = "POST" action = "/HelloWeb/addUser">
         <table>
            <tr>
               <td><form:label path = "username">User Name</form:label></td>
               <td><form:input path = "username" /></td>
            </tr>
            <tr>
               <td><form:label path = "password">Age</form:label></td>
               <td><form:password path = "password" /></td>
            </tr>  
            <tr>
               <td><form:label path = "address">Address</form:label></td>
               <td><form:textarea path = "address" rows = "5" cols = "30" /></td>
            </tr>  
            <tr>
               <td><form:label path = "receivePaper">Subscribe Newsletter</form:label></td>
               <td><form:checkbox path = "receivePaper" /></td>
            </tr> 
            <tr>
               <td><form:label path = "favoriteFrameworks">Favorite Web Frameworks</form:label></td>
               <td><form:checkboxes items = "${webFrameworkList}" path = "favoriteFrameworks" /></td>       
            </tr>
            <tr>
               <td><form:label path = "gender">Gender</form:label></td>
               <td>
                  <form:radiobutton path = "gender" value = "M" label = "Male" />
                  <form:radiobutton path = "gender" value = "F" label = "Female" />
               </td>
            </tr>
            <tr>
               <td><form:label path = "favoriteNumber">Favorite Number</form:label></td>
               <td>
                  <form:radiobuttons path = "favoriteNumber" items = "${numbersList}" />        	
               </td>
            </tr>
            <tr>
               <td><form:label path = "country">Country</form:label></td>
               <td>
                  <form:select path = "country">
                     <form:option value = "NONE" label = "Select"/>
                     <form:options items = "${countryList}" />
                  </form:select>     	
               </td>
            </tr>   	  
            <tr>
               <td colspan = "2">
                  <input type = "submit" value = "Submit"/>
               </td>
            </tr>
         </table>  
      </form:form>
   </body>
</html>

Here, we are using <form:select /> , <form:option /> and <form:options /> tags to render HTML select. For example −

<form:select path = "country">
   <form:option value = "NONE" label = "Select"/>
   <form:options items = "${countryList}" />
</form:select>     	

It will render following HTML content.

<select id = "country" name = "country">
   <option value = "NONE">Select</option>
   <option value = "US">United States</option>
   <option value = "CH">China</option>
   <option value = "MY">Malaysia</option>
   <option value = "SG">Singapore</option>
</select>  

users.jsp

<%@tagpb uri = "http://www.springframework.org/tags/form" prefix = "form"%>
<html>
   <head>
      <title>Spring MVC Form Handpng</title>
   </head>
   <body>
      <h2>Submitted User Information</h2>
      <table>
         <tr>
            <td>Username</td>
            <td>${username}</td>
         </tr>
         <tr>
            <td>Password</td>
            <td>${password}</td>
         </tr>    
         <tr>
            <td>Address</td>
            <td>${address}</td>
         </tr>  
         <tr>
            <td>Subscribed to Newsletter</td>
            <td>${receivePaper}</td>
         </tr>    
         <tr>
            <td>Favorite Web Frameworks</td>
            <td> <% String[] favoriteFrameworks = (String[])request.getAttribute("favoriteFrameworks");
               for(String framework: favoriteFrameworks) {
                  out.println(framework);
               }
            %></td>
         </tr>     	 
         <tr>
            <td>Gender</td>
            <td>${(gender=="M"? "Male" : "Female")}</td>
         </tr>
         <tr>
            <td>Favourite Number</td>
            <td>${favoriteNumber}</td>
         </tr>   
         <tr>
            <td>Country</td>
            <td>${country}</td>
         </tr>   	  
      </table>  
   </body>
</html>

Once you are done with creating source and configuration files, export your apppcation. Right cpck on your apppcation, use the Export → WAR File option and save your HelloWeb.war file in Tomcat s webapps folder.

Now, start the Tomcat server and make sure you are able to access other webpages from webapps folder using a standard browser. Try a URL – http://localhost:8080/HelloWeb/user and we will see the following screen, if everything is fine with the Spring Web Apppcation.

After submitting the required information, cpck on the submit button to submit the form. You should see the following screen, if everything is fine with your Spring Web Apppcation.