1、开发工具和开发环境
开发工具：MyEclipse10，JDK1.6.0_13(32位)，Tomcat7.0（32位），mysql5.7.13
开发环境：WIN10
2、Demo_JSP实现功能
用户登录、用户注册、退出登录。
3、Demo_JSP使用技术
本实例使用了JSP、JDBC来实现用户登录、用户注册和退出登录功能。系统架构图如图一所示：
图一：Demo_JSP系统架构图
下面请看图二（Demo_JSP中JSP文件间逻辑关系图）：
图二：Demo_JSP中JSP文件间逻辑关系图
4、具体实现
（1）在MyEclipse中新建一个Web project项目，并命名为Demo_JSP；
（2）向Demo_JSP项目中导入mysql-connector-java-5.1.6-bin.jar，这个包是实现Java连接数据库功能的包（不会导入包的同学，可以百度哟）；
附：mysql-connector-java-5.1.6-bin.jar百度云下载链接：/s/1i5psdDF 密码：meyg
（3）在Demo_JSP项目中新建以下JSP文件：
1）login.jsp，用户登录的首页界面，代码如下：
<%@ 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>登录界面</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">--></head><body><form name="form1" action="login_action.jsp" method="post"><table width="200" border="1"><tr><td colspan="2">登录窗口</td></tr><tr><td>用户名</td><td><input type="text" name="username" size="10"></td></tr><tr><td>密码</td><td><input type="password" name="password" size="10"></td></tr><tr><td colspan="2"><input type="submit" name="submit" value="登录"> <ahref="register.jsp">注册新用户</a></td></tr></table></form></body></html>
2）login_action.jsp，接收login.jsp页面中用户输入的用户名和密码，通过JDBC实现登录认证，具体代码如下：
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%><%@ include file="inc.jsp"%><%//get parametersString username = request.getParameter("username");String password = request.getParameter("password");//check nullif (username == null || password == null) {response.sendRedirect("login.jsp");}//validateboolean isValid = false;String sql = "select * from userInfo where username='"+username+"' and password='"+password+"'";try {Class.forName(drv).newInstance();Connection conn = DriverManager.getConnection(url, usr, pwd);Statement stm = conn.createStatement();ResultSet rs = stm.executeQuery(sql);if(rs.next())isValid = true;rs.close();stm.close();conn.close();} catch (Exception e) {e.printStackTrace();out.println(e);} finally {}if (isValid) {session.setAttribute("username", username);response.sendRedirect("welcome.jsp");} else {response.sendRedirect("login.jsp");}%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'login_action.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">--></head><body></body></html>
3）inc.jsp，存放数据库连接的地址，具体代码如下：
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%><%String drv = "com.mysql.jdbc.Driver";String url = "jdbc:mysql://localhost:3306/library_system";String usr = "root";String pwd = "root";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'inc.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">--></head><body>This is my JSP page. <br></body></html>
4）welcome.jsp，用户登录成功后的主界面，具体代码如下：
<%@ 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 'welcome.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">--></head><body><table width="100%"><tr><td><img src="images/picture_01.png"></td><td><img src="images/picture_03.jpg" width="600" height="120"></td></tr><tr><td colspan="2"><hr></td></tr><tr><td><table><tr><td><a href="welcome.jsp">Main</a></td></tr><tr><td><a href="menu1.jsp">Menu1</a></td></tr><tr><td><a href="menu2.jsp">Menu2</a></td></tr><tr><td><a href="menu3.jsp">Menu3</a></td></tr><tr><td><a href="menu4.jsp">Menu4</a></td></tr><tr><td><a href="menu5.jsp">Menu5</a></td></tr><tr><td><a href="menu6.jsp">Menu6</a></td></tr><tr><td><a href="menu7.jsp">Menu7</a></td></tr><tr><td><a href="menu8.jsp">Menu8</a></td></tr></table></td><td><form name="form1" action="logout.jsp" method="post"><table width="200" border="1"><tr><td colspan="2">登录成功</td></tr><tr><td>欢迎你，</td><td><%=(String) session.getAttribute("username")%></td></tr><tr><td colspan="2"><input type="submit" name="submit" value="退出"></td></tr></table></form></td></tr></table></body></html>
5）loginout.jsp，用户退出登录，返回登录主界面，具体代码如下：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%session.removeAttribute("username");response.sendRedirect("login.jsp");%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'logout.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">--></head><body></body></html>
6）register.jsp，实现用户注册界面，具体代码如下：
<%@ 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 'register.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">--></head><body><form name="form1" action="register_action.jsp" method="post"><table width="200" border="1"><tr><td colspan="2">注册窗口</td></tr><tr><td>用户名</td><td><input type="text" name="username" size="10"></td></tr><tr><td>密码</td><td><input type="password" name="password1" size="10"></td></tr><tr><td>确认密码</td><td><input type="password" name="password2" size="10"></td></tr><tr><td>Email</td><td><input type="text" name="email" size="10"></td></tr><tr><td colspan="2"><input type="submit" name="submit" value="登录"> <ahref="login.jsp">返回</a></td></tr></table></form></body></html>
7）register_action.jsp，通过JDBC实现注册，并把数据写入数据库，具体代码如下：
<%@ include file="inc.jsp"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><%//get parametersString username = request.getParameter("username");String password1 = request.getParameter("password1");String password2 = request.getParameter("password2");String email = request.getParameter("email");//check nullif (username == null || password1 == null || password2 == null || !password1.equals(password2)) {response.sendRedirect("register.jsp");}//validateboolean isValid = false;String sql = "select * from userInfo where username='"+username+"'";try {Class.forName(drv).newInstance();Connection conn = DriverManager.getConnection(url, usr, pwd);Statement stm = conn.createStatement();ResultSet rs = stm.executeQuery(sql);if(!rs.next()) {sql = "insert into userInfo(username,password,mail) values('"+username+"','"+password1+"','"+email+"')";stm.execute(sql);isValid = true;}rs.close();stm.close();conn.close();} catch (Exception e) {e.printStackTrace();out.println(e);}if (isValid) {response.sendRedirect("login.jsp");} else {response.sendRedirect("register.jsp");}%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><base href="<%=basePath%>"><title>My JSP 'register_action.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">--></head><body></body></html>
5、运行结果展示
（1）在浏览器中输入http://localhost:8080/Demo_JSP/login.jsp，将出现如下图三所示：
图三：登录界面
（2）点击注册新用户，将会出现如下图四所示：
图四：注册界面
（3）注册成功后，会自动返回到登录界面，然后输入用户名和密码，点击登录将出现如下图五所示：
图五：登录后的welcome.jsp界面
附：Demo_JSP项目实例源码百度云下载链接：/s/1mifI8nI 密码：j3wp; 本实例所使用数据库建表sql语句文件下载链接：/s/1eS0n9aM 密码：7ttd
