前言：Servlet3.0帶來了註解的功能，這大大降低了配置xml所花費的時間和精力。以下介紹兩個註解：@WebServlet, @WebFilter
一、@WebServlet註解
1. 說明：該註解用來配置Servlet，其將會在服務器啓動時被tomcat容器處理，容器將根據具體的屬性配置將相應的類部署爲 Servlet。
2. 參數的說明：
3. 實例：
1 package servlet;
2
3 import javax.servlet.ServletException;
4 import javax.servlet.annotation.WebInitParam;
5 import javax.servlet.annotation.WebServlet;
6 import javax.servlet.http.HttpServlet;
7 import javax.servlet.http.HttpServletRequest;
8 import javax.servlet.http.HttpServletResponse;
9 import java.io.IOException;
10
11 @WebServlet(
12 displayName = "LoginServlet" ,
13 name = "UserServlet",
14 urlPatterns = { "/servlet/LoginServlet" },
15 loadOnStartup = 1,
16 initParams = { @WebInitParam(name = "username", value = "Jack") }
17 )
18 public class LoginServlet extends HttpServlet {
19 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
20 doGet(request, response);
21 }
22
23 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
24 String username = request.getParameter("username");
25 String password = request.getParameter("password");
26 if ("admin".equals(username) && "admin".equals(password)) {
27 request.getSession().setAttribute("username", "admin");
28 request.getSession().setAttribute("password", "admin");
29 response.sendRedirect("../sucess.jsp");
30 } else {
31 response.sendRedirect("../failed.jsp");
32 }
33 }
34 }
二、@WebFilter
1. 說明：該註解用來配置過濾器。
2. 參數的說明：
3. 實例：
1 @WebFilter(filterName = "LoginFilter", urlPatterns = "/*", //對所有url進行過濾
2 initParams = {@WebInitParam(name = "url", value = "index.jsp;LoginServlet;error.jsp"), @WebInitParam(name = "encoding", value = "UTF-8")})