Springmvc 简明教程

Spring MVC - RadioButtons Example

以下示例解释了如何在表单中使用 Spring Web MVC 框架中的单选按钮。首先，让我们准备一个能正常工作的 Eclipse IDE，然后按照以下步骤使用 Spring Web 框架开发一个基于动态表单的 Web 应用程序。

The following example explains how to use RadioButtons in forms using the Spring Web MVC framework. To begin with, let us have a working Eclipse IDE in place and follow the subsequent steps to develop a Dynamic Form based Web Application using the 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 chapter.
2	Create Java classes User, UserController under the com.tutorialspointpackage.
3	Create view files user.jsp, users.jsp under the jsp sub-folder.
4	The final step is to create the content of 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;

   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;
   }
}

UserController.java

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.List;

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());
      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;
   }
}

在这里，对于第一个服务方法 user()，我们在 ModelAndView 对象中传递了一个名称为“command”的空白 User 对象，因为如果你在 JSP 文件中使用 <form:form> 标记，Spring 框架会期望一个名称为“command”的对象。因此，当调用 user() 方法时，它会返回 user.jsp 视图。

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 user() method is called, it returns the user.jsp view.

第二个服务方法 addUser() 将针对 HelloWeb/addUser URL 上的 POST 方法进行调用。你将根据提交的信息准备你的模型对象。最后，将在服务方法中返回“users”视图，这会导致呈现 users.jsp。

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

<%@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 colspan = "2">
                  <input type = "submit" value = "Submit"/>
               </td>
            </tr>
         </table>
      </form:form>
   </body>
</html>

在这里，我们使用 <form:radiobuttons /> 标记来呈现 HTML 单选按钮。例如 −

Here, we are using *<form:radiobuttons />*tag to render the HTML radiobuttons. For example −

<form:radiobuttons path = "favoriteNumber" items="${numbersList}" />

它将呈现以下 HTML 内容。

It will render the following HTML content.

<span>
   <input id = "favoriteNumber1" name = "favoriteNumber" type = "radio" value = "1"/>
   <label for = "favoriteNumber1">1</label>
</span>
<span>
   <input id = "favoriteNumber2" name = "favoriteNumber" type = "radio" value = "2"/>
   <label for = "favoriteNumber2">2</label>
</span>
<span>
   <input id = "favoriteNumber3" name = "favoriteNumber" type = "radio" value = "3"/>
   <label for = "favoriteNumber3">3</label>
</span>
<span>
   <input id = "favoriteNumber4" name = "favoriteNumber" type = "radio" value = "4"/>
   <label for = "favoriteNumber4">4</label>
</span>

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>
      </table>
   </body>
</html>

创建源文件和配置文件后，导出应用程序。右键单击应用程序，然后单击 Export → WAR File 选项，并通过 Tomcat 的 webapps 文件夹保存 HelloWeb.war 文件。

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

现在，启动 Tomcat 服务器，确保你可以使用标准浏览器从 webapps 文件夹访问其他网页。尝试以下 URL – http://localhost:8080/HelloWeb/user ，如果 Spring Web 应用程序一切正常，我们将看到以下屏幕。

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

提交所需信息后，单击提交按钮来提交表单。如果你的 Spring Web 应用程序一切正常，我们将看到以下屏幕。

After submitting the required information, click on the submit button to submit the form. We will see the following screen, if everything is fine with your Spring Web Application.