1、在项目中加入MySQL对应的JDBC的驱动jar包
LoginWeb/WebRoot/WEB-INF/lib/mysql-connector-java-3.2.0-alpha-bin.jar
配置文件
- 代码
-
-
<?xml version="1.0" encoding="UTF-8"?>
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<web-app version="2.5"
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xmlns="http://java.sun.com/xml/ns/javaee"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
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http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
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<servlet>
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<description>This is the description of my J2EE component</description>
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<display-name>This is the display name of my J2EE component</display-name>
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<servlet-name>LoginSvlt</servlet-name>
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<servlet-class>com.qdu.sun.LoginSvlt</servlet-class>
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</servlet>
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<servlet-mapping>
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<servlet-name>LoginSvlt</servlet-name>
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<url-pattern>/LoginSvlt</url-pattern>
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</servlet-mapping>
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<filter>
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<filter-name>FormFilter</filter-name>
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<filter-class>com.qdu.sun.FormFilter</filter-class>
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</filter>
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<filter-mapping>
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<filter-name>FormFilter</filter-name>
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<url-pattern>/*</url-pattern>
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</filter-mapping>
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<welcome-file-list>
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<welcome-file>index.jsp</welcome-file>
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</welcome-file-list>
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</web-app>
2、前台页面login.html
- 代码
-
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<title>登录</title>
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<meta http-equiv="content-type" content="text/html; charset=GBK">
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</head>
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<script type="text/javascript">
- // 验证输入不为空的脚本代码
- function checkForm(form) {
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if(form.username.value == "") {
- alert("用户名不能为空!");
- form.username.focus();
- return false;
- }
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if(form.password.value == "") {
- alert("密码不能为空!");
- form.password.focus();
- return false;
- }
- return true;
- }
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</script>
-
<body>
- 请登录
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<br>
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<form action="LoginSvlt" method="post"
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onsubmit="return checkForm(this);">
- 用户名:
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<input type="text" name="username">
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<br>
- 密码:
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<input type="password" name="password">
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<br>
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<input type="submit" value="登录" name="submit1">
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<input type="reset" value="重置" name="reset1">
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</form>
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</body>
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</html>
3、后台处理LoginSvlt.java登录处理
- 代码
-
- package com.qdu.sun;
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- import java.io.IOException;
- import java.io.PrintWriter;
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- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import javax.servlet.http.HttpSession;
- import java.sql.*;
-
- public class LoginSvlt extends HttpServlet {
-
-
- private String username;
- private String password;
- public LoginSvlt() {
- super();
- }
-
-
-
- public void destroy() {
- super.destroy(); // Just puts "destroy" string in log
- // Put your code here
- }
-
- /**
-
* The doGet method of the servlet. <br>
- *
- * This method is called when a form has its tag value method equals to get.
- *
- * @param request the request send by the client to the server
- * @param response the response send by the server to the client
- * @throws ServletException if an error occurred
- * @throws IOException if an error occurred
- */
-
-
- /**
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* The doPost method of the servlet. <br>
- *
- * This method is called when a form has its tag value method equals to post.
- *
- * @param request the request send by the client to the server
- * @param response the response send by the server to the client
- * @throws ServletException if an error occurred
- * @throws IOException if an error occurred
- */
- public void doPost(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
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username=request.getParameter("username");
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password=request.getParameter("password");
- //先定义变量,后使用和关闭
-
Connection conn = null;//声明数据库连接对象
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Statement stmt = null; //声明数据库表达式对象
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ResultSet rs = null;//声明结果集对象
- try {
- // 载入Mysql的驱动字符串
- Class.forName("com.mysql.jdbc.Driver");
- // 获取数据库的连接
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conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/login", "root", "123456");
- // 获取表达式对象实例
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stmt = conn.createStatement();
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rs=stmt.executeQuery("select * from user where username='"+username+"'and password='"+password+"'");
-
- if(rs.next())
- {
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HttpSession session=request.getSession(true);
- session.setAttribute("username", username);
- response.sendRedirect("welcome.jsp");
- }
- else
- {
- response.sendRedirect("error.jsp");
- }
- } catch (Exception e) {
-
- e.printStackTrace();
- }
- }
-
- /**
-
* Initialization of the servlet. <br>
- *
- * @throws ServletException if an error occurs
- */
- public void init() throws ServletException {
- // Put your code here
- }
-
- }
FormFilter.java中文处理
- 代码
-
- package com.qdu.sun;
-
- import java.io.IOException;
- import javax.servlet.Filter;
- import javax.servlet.FilterChain;
- import javax.servlet.FilterConfig;
- import javax.servlet.ServletException;
- import javax.servlet.ServletRequest;
- import javax.servlet.ServletResponse;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletRequestWrapper;
-
- public class FormFilter implements Filter {
- /**
- * Request.java 对 HttpServletRequestWrapper 进行扩充, 不影响原来的功能并能提供所 有的
- * HttpServletRequest 接口中的功能. 它可以统一的对 Tomcat 默认设置下的中文问题进行解决而只 需要用新的 Request
- * 对象替换页面中的 request 对象即可.
- */
- class Request extends HttpServletRequestWrapper {
- public Request(HttpServletRequest request) {
- super(request);
- }
-
- /**
- * 转换由表单读取的数据的内码. 从 ISO 字符转到 GBK.
- */
- public String toChi(String input) {
- try {
-
byte[] bytes = input.getBytes("ISO8859-1");
- return new String(bytes, "GBK");
- } catch (Exception ex) {
- }
- return null;
- }
-
- /**
- * Return the HttpServletRequest holded by this object.
- */
- private HttpServletRequest getHttpServletRequest() {
- return (HttpServletRequest) super.getRequest();
- }
-
- /**
- * 读取参数 -- 修正了中文问题.
- */
- public String getParameter(String name) {
- return toChi(getHttpServletRequest().getParameter(name));
- }
-
- /**
- * 读取参数列表 - 修正了中文问题.
- */
- public String[] getParameterValues(String name) {
- String values[] = getHttpServletRequest().getParameterValues(name);
- if (values != null) {
-
for (int i = 0; i < values.length; i++) {
- values[i] = toChi(values[i]);
- }
- }
- return values;
- }
- }
-
- public void destroy() {
- }
-
- public void doFilter(ServletRequest request, ServletResponse response,
- FilterChain chain) throws IOException, ServletException {
-
HttpServletRequest httpreq = (HttpServletRequest) request;
- if (httpreq.getMethod().equals("POST")) {
- request.setCharacterEncoding("GBK");
- } else {
-
request = new Request(httpreq);
- }
- chain.doFilter(request, response);
- }
-
- public void init(FilterConfig filterConfig) throws ServletException {
- }
- }
4、成功页面
- 代码
-
-
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
-
<%
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String path = request.getContextPath();
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String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
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%>
-
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<base href="<%=basePath%>">
-
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<title>My JSP 'MyJsp.jsp' starting page</title>
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<meta http-equiv="pragma" content="no-cache">
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<meta http-equiv="cache-control" content="no-cache">
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<meta http-equiv="expires" content="0">
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<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
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<meta http-equiv="description" content="This is my page">
-
-
-
-
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</head>
-
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<body>
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欢迎用户:${sessionScope.username}<br>
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</body>
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</html>
本文转自linzheng 51CTO博客,原文链接:http://blog.51cto.com/linzheng/1080838