Servlet的传统配置方式
在JavaWeb开发中, 每次编写一个Servlet都需要在web.xml文件中进行配置,如下所示:
<servlet> <servlet-name>LoginServlet</servlet-name> <servlet-class>com.sponge.LoginServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>LoginServlet</servlet-name> <url-pattern>/login</url-pattern> </servlet-mapping>
每开发一个Servlet,都要在web.xml中配置Servlet才能够使用,这实在是很头疼的事情,所以Servlet3.0之后提供了注解(annotation),使得不再需要在web.xml文件中进行Servlet的部署描述,简化开发流程。
Servlet基于注解的配置方式
在直接在servlet类名上面写以下注解,能达到同样的效果:
@WebServlet("/login")
package com.sponge.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet("/login") public class LoginServlet extends HttpServlet { private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("doGet"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("doPost"); } }