Spring MVC-表单（Form）标签-列表框（Listbox）示例（转载实践）
以下内容翻译自：https://www.tutorialspoint.com/springmvc/springmvc_listbox.htm
说明：示例基于Spring MVC 4.1.6。
以下示例显示如何使用Spring Web MVC框架在表单中使用Listbox。首先，让我们使用Eclipse IDE，并按照以下步骤使用Spring Web Framework开发基于动态窗体的Web应用程序：
| 步骤 | 描述 |
|---|---|
| 1 | 创建一个名为HelloWeb的项目，在一个包com.tutorialspoint下，如Spring MVC - Hello World Example章节所述。 |
| 2 | 在com.tutorialspoint包下创建一个Java类User，UserController。 |
| 3 | 在jsp子文件夹下创建一个视图文件user.jsp，users.jsp。 |
| 4 | 最后一步是创建所有源和配置文件的内容并导出应用程序，如下所述。 |
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; 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
package com.tutorialspoint; 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 "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; } @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 Wicket", "Apache Wicket"); skillList.put("Struts", "Struts"); return skillList; } }
这里第一个服务方法user()，我们已经通过名为“command”的ModelAndView对象中传递了一个空的User对象，因为如果您在JSP中使用<form:form>标签，Spring框架将期望一个名为“command”的对象文件。所以当user()方法被调用时，它返回user.jsp视图。
将在HelloWeb/addUser URL上针对POST方法调用第二个服务方法addUser()。您将根据提交的信息准备您的模型对象。最后，将从服务方法返回“user”视图，这将导致渲染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><form:label path="country">Country</form:label></td> <td> <form:select path="country"> <form:option value="NONE" label="Select"/> <form:options items="${countryList}" /> </form:select> </td> </tr> <tr> <td><form:label path="skills">Skills</form:label></td> <td> <form:select path="skills" items="${skillsList}" multiple="true" /> </td> </tr> <tr> <td colspan="2"> <input type="submit" value="Submit"/> </td> </tr> </table> </form:form> </body> </html>
这里我们使用<form:select />标签，属性multiple = true来呈现HTML列表框。例如
<form:select path="skills" items="${skillsList}" multiple="true" />
它将呈现以下HTML内容。
<select id="skills" name="skills" multiple="multiple"> <option value="Struts">Struts</option> <option value="Hibernate">Hibernate</option> <option value="Apache Wicket">Apache Wicket</option> <option value="Spring">Spring</option> </select> <input type="hidden" name="_skills" value="1"/>
users.jsp
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%> <html> <head> <title>Spring MVC Form Handling</title> </head> <body> <h2>Submitted User Information</h2> <table> <tr> <td>Username</td> <td>${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>${favoriteNumber}</td> </tr> <tr> <td>Country</td> <td>${country}</td> </tr> <tr> <td>Skills</td> <td> <% String[] skills = (String[])request.getAttribute("skills"); for(String skill: skills) { out.println(skill); } %></td> </tr> </table> </body> </html>
完成创建源文件和配置文件后，导出应用程序。右键单击应用程序并使用Export->WAR File选项，并将您的HelloWeb.war文件保存在Tomcat的webapps文件夹中。
现在启动您的Tomcat服务器，并确保您可以使用标准浏览器从webapps文件夹访问其他网页。现在尝试URL http://localhost:8080/HelloWeb/user，如果您的Spring Web应用程序的一切都很好，您应该会看到以下结果：
提交所需信息后，点击提交按钮提交表单。如果您的Spring Web应用程序的一切都很好，您应该会看到以下结果：
Maven示例：
https://github.com/easonjim/5_java_example/tree/master/springmvc/tutorialspoint/test12/
