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2023-12-01

以下示例说明如何使用Spring Web MVC框架在表单中使用多个复选框。首先，让我们使用一个有效的Eclipse IDE，并坚持以下步骤，使用Spring Web Framework开发基于动态表单的Web应用程序。

步	描述
1	在Spring MVC - Hello World章节中解释，在cn.xnip包下创建一个名为HelloWeb的项目。
2	在cn.xnippackage下创建Java类User，UserController。
3	在jsp子文件夹下创建视图文件user.jsp，users.jsp。
4	最后一步是创建源文件和配置文件的内容并导出应用程序，如下所述。

User.java

package cn.xnip;
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)/h2>

package cn.xnip;
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;
   }
}

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为“command”的空白User对象，因为如果使用“form:form”，spring框架需要一个名为“command”的对象。 JSP文件中的标记。因此，当调用user()方法时，它将返回user.jsp视图。

将针对HelloWeb/addUser URL上的POST方法调用第二个服务方法addUser() 。您将根据提交的信息准备模型对象。最后，将从service方法返回“users”视图，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 /》标签来呈现HTML复选框。

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

它将呈现以下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>

完成创建源文件和配置文件后，导出应用程序。右键单击您的应用程序，使用Export → WAR File选项并将您的HelloWeb.war文件保存在Tomcat的webapps文件夹中。

现在，启动Tomcat服务器并确保您能够使用标准浏览器从webapps文件夹访问其他网页。尝试使用URL http://localhost:8080/HelloWeb/user ，如果Spring Web Application的一切正常，我们将看到以下屏幕。

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