无法在 JSP 中的按钮提交操作上加载 servlet答案

【问题标题】：Unable to load servlet on button submit action in JSP无法在 JSP 中的按钮提交操作上加载 servlet
【发布时间】：2015-05-05 20:15:03
【问题描述】：

我有简单的login.jsp 页面：

<form class="form-horizontal" role="form" action="/SchoolERP/Login" method="post">
    <div class="form-group">
        <label for="username" class="control-label col-sm-1">Username:</label>
        <div class="col-sm-5">
            <input type="text" class="form-control" id="username" placeholder="Username">
        </div>
    </div>
    <div class="form-group">
        <label for="password" class="control-label col-sm-1">Password:</label>
        <div class="col-sm-5">
            <input type="password" class="form-control" id="password" placeholder="Password">
        </div>
    </div>
    <div class="col-sm-offset-1 col-sm-5">
        <button type="submit" class="btn btn-default">Submit</button>
    </div>
</form>

我的web.xml 文件包含以下代码：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>SchoolERP</display-name>
  <servlet>
    <servlet-name>SchoolERP</servlet-name>
    <servlet-class>com.rms.school.controllers.ControllerHome</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>SchoolERP</servlet-name>
    <url-pattern>/SchoolERP</url-pattern>
  </servlet-mapping>

  <servlet>
    <servlet-name>Login</servlet-name>
    <servlet-class>com.rms.school.controllers.ControllerLogin</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Login</servlet-name>
    <url-pattern>/SchoolERP/Login</url-pattern>
  </servlet-mapping>

  <welcome-file-list>
    <!-- This welcome filename is linked to above mentioned url-pattern -->
    <welcome-file>SchoolERP</welcome-file>
  </welcome-file-list>

</web-app>

其中ControllerLogin.java如下：

public class ControllerLogin extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        RequestDispatcher rd = request.getRequestDispatcher("jsp/template.jsp");
        request.setAttribute("content_page", "admin/login.jsp");
        request.setAttribute("title", "Login");
        rd.forward(request, response);
    }

}

当我单击 Login.jsp 页面上的提交按钮时，它给出的错误为requested resource /SchoolERP/Login not found。我哪里做错了？

我在 login.jsp 中尝试了各种变体，例如 action="Login"。同样在web.xml 中，我尝试使用Login、/SchoolERP/Login 等。但仍然存在错误。

【问题讨论】：

标签： java forms jsp servlets

【解决方案1】：

终于解决了。我从web.xml 中删除了Login <servlet> 定义，并将注释添加到ControllerLogin servlet 为@WebServlet({"/Login"})。这奏效了。但是我仍然无法理解上面的代码哪里出错了？

【讨论】：