• 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/

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  • 原文地址:https://www.cnblogs.com/EasonJim/p/7476126.html
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