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Servlet入门代码

编程日记 2023/12/09 21:45:20

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1. 第一个Servlet程序

package com.allanlxf.serv.basic;
import javax.servlet.*;
import java.io.*;
public class TimeServlet implements Servlet
{private ServletConfig config;public TimeServlet(){System.out.println("TimeServlet()");}public void init(ServletConfig config) throws ServletException{this.config = config;System.out.println("init(" + config + ")");}public void service(ServletRequest request, ServletResponse response)throws ServletException, IOException{System.out.println(this);System.out.println("service(" + request + "," + response + ")");getServletConfig();PrintWriter out = response.getWriter();out.println("<h1>");out.println(new java.util.Date());out.println("</h1>");out.close();}public void destroy(){System.out.println("destroy");}public String getServletInfo(){return "time servlet by allan version 1.0";}public ServletConfig getServletConfig(){return config;}  
}

2. 编写及布署Servlet类

(1)编写一个类继承自HttpServlet

package com.allanlxf.serv.basic;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class HttpTimeServlet extends HttpServlet
{public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException{response.setContentType("text/html");PrintWriter out = response.getWriter();out.println("<html>");out.println("<head>");out.println("<title>currentTime</title>");out.println("</head>");out.println("<body>");out.println("<h3 align="center">Current Time is</h3>");out.println("<hr>");out.println(new java.util.Date());out.println("</body>");out.println("</html>");out.close();}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException{doGet(request, response);}
}

(2)在Tomcat中布署一个myFirst-app web应用

---Tomcat

---webapps

---myFirst-app

---WEB-INF

---classes

---web.xml

---shoppingCart

(3)配置Web.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app 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"version="2.4"><servlet> <servlet-name>ActionServlet</servlet-name><servlet-class>org.apache.struts.action.ActionServlet</servlet-class><load-on-startup>1</load-on-startup></servlet>  <servlet><servlet-name>time</servlet-name><servlet-class>com.allanlxf.serv.basic.TimeServlet</servlet-class><load-on-startup>1</load-on-startup></servlet><servlet><servlet-name>HttpTimeServlet</servlet-name><servlet-class>com.allanlxf.serv.basic.HttpTimeServlet</servlet-class></servlet><servlet-mapping> <servlet-name>ActionServlet</servlet-name><url-pattern>*.do</url-pattern></servlet-mapping><servlet-mapping><servlet-name>time</servlet-name><url-pattern>/basic/time</url-pattern></servlet-mapping><servlet-mapping><servlet-name>HttpTimeServlet</servlet-name><url-pattern>/basic/http/time</url-pattern></servlet-mapping>
<listener><listener-class>com.chu.shoppingCart.web.shoppingCartListner</listener-class></listener>
</web-app>

3. 常用类介绍

(1)Filter类

public class CharacterEncodingFilter implements Filter
{private FilterConfig config;public void init(FilterConfig config) throws ServletException{        this.config = config;}public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException{String encoding = config.getInitParameter("encoding");if(encoding == null){encoding = "gbk";}request.setCharacterEncoding(encoding);response.setCharacterEncoding(encoding);chain.doFilter(request, response);}public void destroy(){}
}

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