web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>servlet-test</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>MySer</servlet-name> <servlet-class>test1.MySer</servlet-class> </servlet> <servlet-mapping> <servlet-name>MySer</servlet-name> <url-pattern>/servlet/MySer</url-pattern> </servlet-mapping> </web-app>
mySer
package test1; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class MySer extends HttpServlet{ /** * */ private static final long serialVersionUID = 1L; @Override protected void service(HttpServletRequest request, HttpServletResponse response) throws IOException,ServletException{ System.out.println("fa"); if(request.getMethod().equals("POST")){ doPost(request, response); } //一个servlet默认会执行service方法，service方法中会转向doget或者dopost(doget,dopost如果被子类覆盖， //那个就执行子类的。如果你在子类中覆盖了service 方法，那么是否执行doget或者dopost ，就成为service方法 //的代码问题了) } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); System.out.println("get"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ System.out.print("post"); request.setAttribute("msg", "登陆成功"); request.getRequestDispatcher("/success.jsp").forward(request, response);
//response.sendRedirect("/success.jsp");
//重定向是客户端发出的请求，所以是response请求，url地址栏改变
//请求转发是服务端发出的，所以是request请求，url地址栏不变
} }
index.jsp
<?xml version="1.0" encoding="utf-8" ?> <%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Insert title here</title> </head> <body> <form action="/servlet/MySer" name="f" method="post"> <input type="text" value="" name="usename"/> <input type="password" value="" name="password"/> <input type="submit" value="dengl"/> </form> </body> </html>
需要把 javax.servlet. servlet-api.jar 放到lib下。
记得把Java build path - source 的 output folder 设置为 项目名/webapp/WEB-INF/classes下