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。

Step

Description

1

按照 Spring MVC - Hello World 章节中的说明，使用 com.tutorialspoint 作为包，创建一个名为 HelloWeb 的项目。

2

在 com.tutorialspointpackage 下创建 Java 类 User 和 UserController。

3

在 jsp 子文件夹下创建视图文件 user.jsp 和 users.jsp。

4

最后一步是创建源文件和配置文件的内容，然后按如下所述导出应用程序。

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。

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。

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。

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

它会呈现以下 HTML 内容。

<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。

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。

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。

spring checkboxes result