Springmvc 简明教程

Spring MVC - Checkboxes Example

以下示例介绍了如何在表单中使用多个复选框，方法是使用 Spring Web MVC 框架。首先，让我们提供一个可用的 Eclipse IDE，并严格按照以下步骤使用 Spring Web 框架开发基于动态表单的 Web 应用程序。

The following example explains how to use Multiple Checkboxes in forms using the Spring Web MVC framework. To start with, let us have a working Eclipse IDE in place and stick to the following 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;

   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;
   }
}

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"}));
	  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());
      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;
   }
}

在这里，对于第一个服务方法 user() ，我们在 ModelAndView 对象中传递了一个空白 User 对象，名称为“command”，这是因为如果你在 JSP 文件中使用 <form:form> 标记，则 Spring 框架需要一个名为“command”的对象。因此，当调用 user() 方法时，它将返回 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 the user() method is called, it returns the user.jsp view.

第二个服务方法 addUser() 将相对于 HelloWeb/addUser URL 上的 POST 方法调用。你将根据提交的信息准备模型对象。最后，“users”视图将从服务方法返回，这将导致呈现 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 colspan = "2">
                  <input type = "submit" value = "Submit"/>
               </td>
            </tr>
         </table>
      </form:form>
   </body>
</html>

在这里，我们使用 <form:checkboxes /> 标记呈现 HTML 复选框。

Here, we are using <form:checkboxes /> tag to render HTML checkboxes.

<form:checkboxes items = "${webFrameworkList}" path = "favoriteFrameworks" />

它会呈现以下 HTML 内容。

It will render following HTML content.

<span>
   <input id = "favoriteFrameworks1" name = "favoriteFrameworks" type = "checkbox" value = "Spring MVC" checked = "checked"/>
   <label for = "favoriteFrameworks1">Spring MVC</label>
</span>
<span>
   <input id = "favoriteFrameworks2" name = "favoriteFrameworks" type = "checkbox" value = "Struts 1"/>
   <label for = "favoriteFrameworks2">Struts 1</label>
</span>
<span>
   <input id = "favoriteFrameworks3" name = "favoriteFrameworks" type = "checkbox" value = "Struts 2" checked = "checked"/>
   <label for = "favoriteFrameworks3">Struts 2</label>
</span>
<span>
   <input id = "favoriteFrameworks4" name = "favoriteFrameworks" type = "checkbox" value = "Apache Wicket"/>
   <label for = "favoriteFrameworks4">Apache Wicket</label>
</span>
<input type = "hidden" name = "_favoriteFrameworks" value = "on"/>

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

在您创建了源文件和配置文件以后，导出您的应用程序。右键单击您的应用程序，使用 Export → WAR File 选项，并保存在Tomcat的webapps文件夹中。

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 your HelloWeb.war file in Tomcat’s webapps folder.

现在，启动Tomcat服务器，并确保您能通过标准浏览器访问webapps文件夹中的其它网页。尝试一个URL http://localhost:8080/HelloWeb/user ，如果Spring Web应用程序正常，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 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 Application.

spring checkboxes

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.

spring checkboxes result