以下示例显示如何在使用Spring Web MVC框架的表单中使用列表框(Listbox)。首先使用Eclipse IDE来创建一个WEB工程，实现一个让用户可选择自己所善长的技术(多选)的功能。并按照以下步骤使用Spring Web Framework开发基于动态表单的Web应用程序：
- 创建一个名称为 Listbox 的动态WEB项目。
- 在
com.zaixian.springmvc包下创建两个Java类User，UserController。 - 在
jsp子文件夹下创建两个视图文件：user.jsp，userlist.jsp。 - 最后一步是创建所有源和配置文件的内容并运行应用程序，详细如下所述。
完整的项目文件目录结构如下所示 -
User.java 的代码如下所示 -
package com.zaixian.springmvc;
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;
private String [] skills;
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;
}
public String[] getSkills() {
return skills;
}
public void setSkills(String[] skills) {
this.skills = skills;
}
}
UserController.java 的代码如下所示 -
package com.zaixian.springmvc;
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());
model.addAttribute("skills", user.getSkills());
return "userlist";
}
@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 Hadoop");
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;
}
@ModelAttribute("skillsList")
public Map<String, String> getSkillsList()
{
Map<String, String> skillList = new HashMap<String, String>();
skillList.put("Hibernate", "Hibernate");
skillList.put("Spring", "Spring");
skillList.put("Apache Hadoop", "Apache Hadoop");
skillList.put("Struts", "Struts");
return skillList;
}
}
这里的第一个服务方法user()，我们已经在ModelAndView对象中传递了一个名称为“command”的空User对象，因为如果在JSP文件中使用<form:form>标签，spring框架需要一个名称为“command”的对象。 所以当调用user()方法时，它返回user.jsp视图。
第二个服务方法addUser()将根据URL => Listbox/addUser 上的POST方法请求时调用。根据提交的信息准备模型对象。 最后从服务方法返回“userlist”视图，这将呈现userlist.jsp视图。
user.jsp 的代码如下所示 -
<%@ page contentType="text/html; charset=UTF-8"%>
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<head>
<title>Spring MVC表单处理(列表框)</title>
</head>
<body>
<h2>用户信息</h2>
<form:form method="POST" action="/Listbox/addUser">
<table>
<tr>
<td><form:label path="username">用户名：</form:label></td>
<td><form:input path="username" /></td>
</tr>
<tr>
<td><form:label path="password">密码：</form:label></td>
<td><form:password path="password" /></td>
</tr>
<tr>
<td><form:label path="address">地址：</form:label></td>
<td><form:textarea path="address" rows="5" cols="30" /></td>
</tr>
<tr>
<td><form:label path="receivePaper">是否订阅：</form:label></td>
<td><form:checkbox path="receivePaper" /></td>
</tr>
<tr>
<td><form:label path="favoriteFrameworks">喜欢的框架/技术：</form:label></td>
<td><form:checkboxes items="${webFrameworkList}"
path="favoriteFrameworks" /></td>
</tr>
<tr>
<td><form:label path="gender">性别：</form:label></td>
<td><form:radiobutton path="gender" value="M" label="男" /> <form:radiobutton
path="gender" value="F" label="女" /></td>
</tr>
<tr>
<td><form:label path="favoriteNumber">喜欢的数字：</form:label></td>
<td><form:radiobuttons path="favoriteNumber"
items="${numbersList}" /></td>
</tr>
<tr>
<td><form:label path="country">所在国家：</form:label></td>
<td><form:select path="country">
<form:option value="NONE" label="请选择..." />
<form:options items="${countryList}" />
</form:select></td>
</tr>
<tr>
<td><form:label path="skills">技术：</form:label></td>
<td><form:select path="skills" items="${skillsList}"
multiple="true" /></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="提交" /></td>
</tr>
</table>
</form:form>
</body>
</html>
这里使用<form:select /> 及其属性 multiple=true标签来呈现HTML列表多选框。 例如 -
<form:select path="skills" items="${skillsList}" multiple="true" />
它将呈现以下HTML内容。
<select id="skills" name="skills" multiple="multiple">
<option value="Struts">Struts</option>
<option value="Hibernate">Hibernate</option>
<option value="Apache Wicket">Apache Hadoop</option>
<option value="Spring">Spring</option>
</select>
<input type="hidden" name="_skills" value="1"/>
userlist.jsp 的代码如下所示 -
<%@ page contentType="text/html; charset=UTF-8"%>
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<head>
<title>Spring MVC表单处理(列表框)</title>
</head>
<body>
<h2>提交用户信息 -</h2>
<table>
<tr>
<td>用户名：</td>
<td>${username}</td>
</tr>
<tr>
<td>密码：</td>
<td>${password}</td>
</tr>
<tr>
<td>地址：</td>
<td>${address}</td>
</tr>
<tr>
<td>是否订阅：</td>
<td>${receivePaper}</td>
</tr>
<tr>
<td>喜欢的技术/框架：</td>
<td>
<%
String[] favoriteFrameworks = (String[]) request.getAttribute("favoriteFrameworks");
for (String framework : favoriteFrameworks) {
out.println(framework);
}
%>
</td>
</tr>
<tr>
<td>性别：</td>
<td>${(gender=="M"? "男" : "女")}</td>
</tr>
<tr>
<td>喜欢的数字：</td>
<td>${favoriteNumber}</td>
</tr>
<tr>
<td>国家：</td>
<td>${country}</td>
</tr>
<tr>
<td>技术：</td>
<td>
<%
String[] skills = (String[]) request.getAttribute("skills");
for (String skill : skills) {
out.println(skill);
}
%>
</td>
</tr>
</table>
</body>
</html>
完成创建源和配置文件后，发布应用程序到Tomcat服务器。
现在启动Tomcat服务器，现在尝试访问URL => http://localhost:8080/Listbox/user ，如果Spring Web应用程序没有问题，应该看到以下结果：
提交所需信息后，点击提交按钮提交表单。 如果Spring Web应用程序没有问题，应该看到以下结果：
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