day13-Servlet03

时间2025-05-04 23:39:51分类IT科技浏览3117

导读：Servlet03 11.练习...

Servlet03

11.练习

快捷键-可以快速地在访问的文件件切换

ctrl+alt+向左箭头：回到上次访问的位置

ctrl+alt+向右箭头：回到下一步访问的位置

11.1CatServlet

首先创建项目servlet ，配置好Tomcat ，添加web应用支持。在web目录下面的WEB-INF目录下创建lib目录，在Tomcat安装包的lib目录中找到servlet-api ，并添加到idea的web目录下面的WEB-INF/lib目录，选择引用为库文件

在src目录下创建目录，编写CatServlet类：

package servlet; import javax.servlet.*; import javax.servlet.http.HttpServletRequest; import java.io.IOException; public class CatServlet implements Servlet { public int count = 0; @Override public void init(ServletConfig servletConfig) throws ServletException { } @Override public ServletConfig getServletConfig() { return null; } @Override public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException { count++;//每次访问service方法，count累加 System.out.println("该servlet访问次数=" + count); //获取请求的方式 HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest; String method = httpServletRequest.getMethod(); if (method.equals("GET")) { doGet(); } else if (method.equals("POST")) { doPost(); } } public void doGet() { System.out.println("CatServlet doGet()..."); } public void doPost() { System.out.println("CatServlet doPost()..."); } @Override public String getServletInfo() { return null; } @Override public void destroy() { } }

在web.xml文件中进行Servlet配置：

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <servlet> <servlet-name>CatServlet</servlet-name> <servlet-class>servlet.CatServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>CatServlet</servlet-name> <url-pattern>/cat</url-pattern> </servlet-mapping> </web-app>

在WEB-INF目录下编写一个html ，用于测试

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>login</title> </head> <body> <form action="http://localhost:8080/servlet/cat" method="get"> name: <input type="text"/><br/><br/> <input type="submit" value="login"/> </form> </body> </html>

点击启动Tomcat ，在浏览器中输入地址：http://localhost:8080/servlet/login.html

点击login按钮，成功跳转到CatServlet中：

后台输出：（如果表单方式改变了，仍然调用的是旧的访问方法，点击保存html，并刷新浏览器页面即可解决）

11.2DogServlet

在11.1的项目框架上进行编程

首先在src目录下创建DogServlet类

package servlet; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; public class DogServlet extends HttpServlet { private int getCount = 0; private int postCount = 0; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { getCount++; System.out.println("getCount=" + getCount); System.out.println("DogServlet-访问doGet()"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { postCount++; System.out.println("postCount=" + postCount); System.out.println("DogServlet-访问doPost()"); } }

注意：这里没有重写service方法，因此当浏览器请求DogServlet时，会去父类HttpServlet类中去找调用的service方法，在HttpServlet类中的service方法会根据请求类型如get 、post去调用当前运行类型（即DogServlet）的doPost 、doGet方法，因此在自己创建的Servlet中不用判断请求方式

在web.xml文件中配置该Servlet:

<servlet> <servlet-name>DogServlet</servlet-name> <servlet-class>servlet.DogServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>DogServlet</servlet-name> <url-pattern>/dog</url-pattern> </servlet-mapping>

修改之前的login.html文件

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>login</title> </head> <body> <form action="http://localhost:8080/servlet/dog" method="post"> name: <input type="text"/><br/><br/> <input type="submit" value="login"/> </form> </body> </html>

点击redeploy Tomcat ，在浏览器输入地址http://localhost:8080/servlet/login.html ，点击login按钮，成功跳转到DogServlet

将login.html文件中表单提交方式反复该为post或者get ，多次访问，后台输出如下：

（如果表单方式改变了，仍然调用的是旧的访问方法，点击保存html ，并刷新浏览器页面即可解决）

11.3PigServlet

在11.1的项目框架上进行编程

在src目录下编写PigServlet

package servlet; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet(urlPatterns = {"/pig1", "/pig2"},loadOnStartup = 1) public class PigServlet extends HttpServlet { private int getCount = 0; private int postCount = 0; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { getCount++; System.out.println("PigServlet-访问doGet()-get访问次数=" + getCount); System.out.println("客户端地址="+req.getRemoteAddr()); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { postCount++; System.out.println("PigServlet-访问doPost()-post访问次数=" + postCount); System.out.println("客户端地址="+req.getRemoteAddr()); } }

修改login.html文件

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>login</title> </head> <body> <form action="http://localhost:8080/servlet/pig1" method="get"> name: <input type="text"/><br/><br/> <input type="submit" value="login"/> </form> </body> </html>

点击redeploy Tomcat，在浏览器输入地址http://localhost:8080/servlet/login.html ，点击login按钮，成功跳转到PigServlet

将login.html文件中表单提交方式反复改为post或者get，多次访问，后台输出如下：