Spring MVC - Dropdown Example

The following example show how to use Dropdown in forms using Spring Web MVC framework. To start with it, let us have working Eclipse IDE in place and follow the following steps to develop a Dynamic Form based Web Application using Spring Web Framework:

Step	Description
1	Create a project with a name HelloWeb under a package com.tutorialspoint as explained in the Spring MVC - Hello World Example chapter.
2	Create a Java classes User, UserController under the com.tutorialspoint package.
3	Create a view files user.jsp, users.jsp under jsp sub-folder.
4	The final step is to create the content of all the source and configuration files and export the application as explained below.

User.java

package com.tutorialspoint;

public 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;
   
   public String getUsername() {
      return username;
   }
   public void setUsername(String username) {
      this.username = username;
   }

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

   @RequestMapping(value = "/user", method = RequestMethod.GET)
   public 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)
   public 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")
   public 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")
   public 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")
   public 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 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 user() method is called it returns user.jsp view.
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 a "users" view will be returned from the service method, which will result in rendering users.jsp
user.jsp

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<head>
   <title>Spring MVC Form Handling</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're 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

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<head>
    <title>Spring MVC Form Handling</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 application. Right click on your application and use Export > WAR File option and save your HelloWeb.war file in Tomcat's webapps folder.
Now start your Tomcat server and make sure you are able to access other web pages from webapps folder using a standard browser. Now try a URL http://localhost:8080/HelloWeb/user and you should see the following result if everything is fine with your Spring Web Application:
After submitting required information click on submit button to submit the form. You should see the following result if everything is fine with your Spring Web Application: