项目结构：
java文件：
public class HelloWorld extends HttpServlet {
public HelloWorld() {
super();
}
public void destroy() {
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println(request.getParameter("uname"));
}
}<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name></display-name>
<servlet>
<servlet-name>HelloWorld</servlet-name>
<servlet-class>test.HelloWorld</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorld</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
</web-app> <body>
<form action="login">
username:<input type="text" name="uname"><br>
password:<input type="password" name="pwd"><br>
<input type="submit">
</form>
</body>
输出截图：
这样一个简单的登录servlet实例就完成啦