myeclipse servlet的基本运用

来源：互联网发布：cxax2013车床软件编辑：程序博客网时间：2024/05/24 22:44

1.servlet:以数据为基础，不是独立存在与服务器上的网页文件

2.c/s负荷轻，维护成本高,b/s的负荷重，维护成本低

3.servlet的init(）在执行时已被初始化，只一次； destroy()在服务器正常被关闭时销毁

4.改变初始化时间 <load-on-startup>1</load-on-startup>

5.servlet从前端页面获取数据 String qq=request.getParameter("qq");

LoginSeverlet

package com.jkx.web.servlet;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.jkx.dao.UserDao;import com.jkx.po.User;public class LoginServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html");response.setCharacterEncoding("utf-8");PrintWriter out =response.getWriter();String qq=request.getParameter("qq");String pass=request.getParameter("pass");UserDao userdao=UserDao.getIntance();User user=userdao.getUserByusernameAndPasswoed(qq, pass);if(user!=null)System.out.println("登录成功");elseSystem.out.println("登录失败");out.flush();out.close();}//public void service(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException//{//response.setContentType("text/html");//response.setCharacterEncoding("utf-8");//System.out.println(request.getMethod());//获得传递方式//System.out.println(request.getRequestURI());//System.out.println(request.getContextPath());//String qq=request.getParameter("qq");//String pass=request.getParameter("pass");//System.out.println(qq+"\n"+pass);//PrintWriter out =response.getWriter();//out.println("dddddd 阿萨德<font color='red'>1111</font>");////out.flush();//out.close();//}}

前端代码：

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  <style type="text/css">*{padding:0;margin:0;font-family:"微软雅黑";font-size:14px;}#warp{width:900px;height:800px; margin:0 auto;}#yx{height:390px;width:340px;border:1px solid #0099ff;border-radius:6px;margin:80px auto;}#yx_h{width:340px;height:50px;border-bottom:1px solid #0099ff;background:#00cccc;}#yx_h .span1{display:block;height:50px;width:170px;float:left;line-height:50px;text-align:center;cursor:pointer;font-size:16px;}#yx_h .span1:hover{background:#339999;}#yx_h .span2:hover{background:#339999;}#yx_h .span2{display:block;height:50px;width:170px;float:right;line-height:50px;text-align:center;cursor:pointer;font-size:16px;}#yx_b{width:290px;height:262px;padding:24px;}#yx_b span{width:286px;height:36px;display:block;line-height:36px;}#yx_b span input{width:286px;height:36px;border:1px solid #0099ff;margin-top:20px;display:block;padding-left:10px;}#yx_b span .chbox{width:18px;height:18px;float:left;line-height:20px;}#yx_b span .fot{width:250px;height:36px;display:block;float:right;margin-top:12px;margin-left:10px;font-size:12px;}#yx_b span .sub{color:#fff;font-size:16px;background:#0099ff;cursor:pointer;border-radius:5px;}#yx_b span .sub:hover{background:#3399cc;}#yx_t{width:340px;height:50px;}#yx_t span{width:312px;height:20px;display:inline-block;text-align:right;padding-right:24px;color:#0099cc;}#yx_t span a{text-decoration:none;color:#0099cc;}#yx_t span a:hover{text-decoration:underline;}  </style>  </head>    <body>  <form action="LoginServlet" method="post">    <div id="warp"><div id="yx"><div id="yx_h"><span class="span1">快速登录</span><span class="span2">账号密码登录</span></div><div id="yx_b"><span><input type="text" placeholder="支持QQ号/邮箱/手机号登录" name="qq"/></span><span><input type="password" placeholder="QQ密码" name="pass"/></span><span><input type="checkbox" class="chbox"><span class="fot">下次自动登录</span></span><span><input type="submit" class="sub" value="登     录"/></span></div><div id="yx_t"><span><a href="javascript:;">忘记密码?</a>  |<a href="javascript:;">注册新账号</a> |<a href="javascript:;">意见反馈</a></span></div></div></div></form>  </body></html>

6.PrintWriter out =response.getWriter(); out.println("dddddd");//以文本的形式输出servlet中需要输出的内容
7.response.setContentType("text/html");//不加若有标签则标签一起打印；response.setCharacterEncoding("utf-8");中文乱码问题
8.request.getMethod();//获得传递方式 getContextPath、getRequestURL分别是获得项目名和域名端口号以后的部分，不包含参数，getScheme()获取协议名，getRequestPath等

9.获取网络连接的信息 getRemoteAddr() 返回客户端的ip地址 getRemotePort()返回客户端发出请求的端口等

10.创建servlet，在项目里面新建一个servlet文件→命名后→注意删除红圈部分

11.编写servlet代码

package com.jkx.web.servlet;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class FirstServlet extends HttpServlet {public void destroy() {System.out.println("FirstServlet被销毁");}public void init() throws ServletException {System.out.println("FirstServlet被初始化");}public void service(HttpServletRequest request, HttpServletResponse response){System.out.println("111111-------------------------");}}

13.具体项目请参照http://download.csdn.net/download/qq_28316183/9969872

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