架構實例之Demo_JSP
1、開發工具和開發環境
開發工具： MyEclipse10，JDK1.6.0_13(32位)，Tomcat7.0（32位），mysql5.7.13
開發環境：WIN10
2、Demo_JSP實現功能
用戶登錄、用戶注冊、退出登錄。
3、Demo_JSP使用技術
本實例使用了JSP、JDBC來實現用戶登錄、用戶注冊和退出登錄功能。系統架構圖如圖一所示：
圖一：Demo_JSP系統架構圖
下面請看圖二（Demo_JSP中JSP文件間邏輯關系圖）：
圖二：Demo_JSP中JSP文件間邏輯關系圖
4、具體實現
（1）在MyEclipse中新建一個Web project項目，並命名為Demo_JSP；
（2）向Demo_JSP項目中導入mysql-connector-java-5.1.6-bin.jar，這個包是實現Java連接數據庫功能的包（不會導入包的同學，可以百度喲）；
附：mysql-connector-java-5.1.6-bin.jar百度雲下載鏈接：http://pan.baidu.com/s/1i5psdDF 密碼：meyg
（3）在Demo_JSP項目中新建以下JSP文件：
1）login.jsp，用戶登錄的首頁界面，代碼如下：
<%@ 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>登錄界面</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">登錄窗口</td>
</tr>
<tr>
<td>用戶名</td>
<td><input type="text" name="username" size="10"></td>
</tr>
<tr>
<td>密碼</td>
<td><input type="password" name="password" size="10"></td>
</tr>
<tr>
<td colspan="2"><input type="submit" name="submit" value="登錄"> <a
href="register.jsp">注冊新用戶</a></td>
</tr>
</table>
</form>
</body>
</html>
2）login_action.jsp，接收login.jsp頁面中用戶輸入的用戶名和密碼，通過JDBC實現登錄認證，具體代碼如下：
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%>
<%@ include file="inc.jsp"%>
<%
//get parameters
String username = request.getParameter("username");
String password = request.getParameter("password");
//check null
if (username == null || password == null) {
response.sendRedirect("login.jsp");
}
//validate
boolean 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，存放數據庫連接的地址，具體代碼如下：
<%@ 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，用戶登錄成功後的主界面，具體代碼如下：
<%@ 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">登錄成功</td>
</tr>
<tr>
<td>歡迎你，</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，用戶退出登錄，返回登錄主界面，具體代碼如下：
<%@ 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，實現用戶注冊界面，具體代碼如下：
<%@ 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">注冊窗口</td>
</tr>
<tr>
<td>用戶名</td>
<td><input type="text" name="username" size="10"></td>
</tr>
<tr>
<td>密碼</td>
<td><input type="password" name="password1" size="10"></td>
</tr>
<tr>
<td>確認密碼</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="登錄"> <a
href="login.jsp">返回</a></td>
</tr>
</table>
</form>
</body>
</html>
7）register_action.jsp，通過JDBC實現注冊，並把數據寫入數據庫，具體代碼如下：
<%@ include file="inc.jsp"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%
//get parameters
String username = request.getParameter("username");
String password1 = request.getParameter("password1");
String password2 = request.getParameter("password2");
String email = request.getParameter("email");
//check null
if (username == null || password1 == null || password2 == null || !password1.equals(password2)) {
response.sendRedirect("register.jsp");
}
//validate
boolean 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、運行結果展示
（1）在浏覽器中輸入http://localhost:8080/Demo_JSP/login.jsp，將出現如下圖三所示：
圖三：登錄界面
（2）點擊注冊新用戶，將會出現如下圖四所示：
圖四：注冊界面
（3）注冊成功後，會自動返回到登錄界面，然後輸入用戶名和密碼，點擊登錄將出現如下圖五所示：
圖五：登錄後的welcome.jsp界面
附：Demo_JSP項目實例源碼百度雲下載鏈接：http://pan.baidu.com/s/1mifI8nI 密碼：j3wp; 本實例所使用數據庫建表sql語句文件下載鏈接：http://pan.baidu.com/s/1eS0n9aM 密碼：7ttd
