Jsp+Servlet+Tomcat+Mysql+JDBC+MVC模式简单实用范例

it2025-12-23 12

这里用到的软件分别如下：

Tomcat：apache-tomcat-6.0.29.zip

Mysql：mysql-essential-5.1.50-win32.msi

JDBC：mysql-connector-java-5.1.13-bin.jar

Myeclipse：myeclipse-8.6.0-win32.exe

这里要做的配置如下：

mysql默认安装，建立root账户，密码root

mysql-connector-java-5.1.13-bin.jar放到Web应用的WEB-INF/lib/目录下或者是tomcat的lib/目录下

这里要制作的效果如下：

登录页面：

注销页面：

这里用到的关键代码如下：

SQL:

create database test; use test; CREATE TABLE test. user ( pid varchar ( 45 ) default NULL , username varchar ( 45 ) NOT NULL , password varchar ( 45 ) NOT NULL ) DEFAULT CHARSET = GB2312; INSERT user (pid, username, password) VALUES ( ' 1 ' , ' root ' , ' root ' ); INSERT user (pid, username, password) VALUES ( ' 2 ' , ' admin ' , ' admin ' );

首页（视图）：

1 < body > 2 <% if ( null ! = session.getAttribute( " username " )) { %> 3 欢迎您回来： <% = session.getAttribute( " username " ) %> 4 < a href ="servlet/ServletLogout" > 注销 </ a >< br /> 5 < br /> 6 <% } else { %> 7 < form action ="servlet/ServletLogin" method ="POST" > 8 < input type ="text" name ="username" />< br /> 9 < input type ="password" name ="password" />< br /> 10 < input type ="submit" value ="登录" /> 11 </ form > 12 <% } %> 13 在线会员人数： <% = application.getAttribute( " onlineMember " ) %> < br /> 14 当前在线人数： <% = application.getAttribute( " onlineNumber " ) %> < br /> 15 历史访问人数： <% = application.getAttribute( " totalNumber " ) %> < br /> 16 </ body >

1 public void doGet(HttpServletRequest request, HttpServletResponse response) 2 throws ServletException, IOException { 3 4 HttpSession session = request.getSession(); 5 ServletContext application = this .getServletContext(); 6 7 if ( null == session.getAttribute( " username " )) { 8 try { 9 // 获得表单数据 10 String username = request.getParameter( " username " ); 11 String password = request.getParameter( " password " ); 12 13 // 建立数据库连接 14 Connection conn = DBUtil.getConnection(); 15 16 // 定义查询语句 17 String sql = " select * from user where `username`=? and `password`=? " ; 18 PreparedStatement pstmt = conn.prepareStatement(sql); 19 pstmt.setString( 1 , username); 20 pstmt.setString( 2 , password); 21 22 // 查询获得结果集 23 ResultSet rs = pstmt.executeQuery(); 24 if (rs.next()) { 25 session.setAttribute( " username " , rs.getString( " username " )); 26 // session.setAttribute("password", rs.getString("password")); 27 int olMember = ((Integer) application.getAttribute( " onlineMember " )).intValue(); 28 application.setAttribute( " onlineMember " , olMember + 1 ); 29 } 30 31 // 关闭结果集，查询语句，数据库连接 32 rs.close(); 33 pstmt.close(); 34 conn.close(); 35 } catch (InstantiationException e) { 36 // TODO Auto-generated catch block 37 e.printStackTrace(); 38 } catch (IllegalAccessException e) { 39 // TODO Auto-generated catch block 40 e.printStackTrace(); 41 } catch (ClassNotFoundException e) { 42 // TODO Auto-generated catch block 43 e.printStackTrace(); 44 } catch (SQLException e) { 45 // TODO Auto-generated catch block 46 e.printStackTrace(); 47 } 48 } 49 50 // 返回上一个页面 51 response.sendRedirect(request.getHeader( " Referer " )); 52 }

注销（控制器）：

数据库（模型）：

1 public class DBUtil { 2 private static String username = " root " ; 3 private static String password = " root " ; 4 private static String driver = " com.mysql.jdbc.Driver " ; 5 private static String url = " jdbc:mysql://localhost:3306/test " ; 6 7 // 得到数据库连接 8 public static Connection getConnection() throws InstantiationException, IllegalAccessException, ClassNotFoundException, SQLException { 9 Class.forName(driver).newInstance(); 10 return DriverManager.getConnection(url, username, password); 11 } 12 13 }

Web配置页面：

1 <? xml version="1.0" encoding="UTF-8" ?> 2 < web-app version ="2.5" xmlns ="http://java.sun.com/xml/ns/javaee" 3 xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation ="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" > 5 < listener > 6 < listener-class > listener.WebListener </ listener-class > 7 </ listener > 8 < servlet > 9 < servlet-name > ServletWebInitializer </ servlet-name > 10 < servlet-class > servlet.ServletWebInitializer </ servlet-class > 11 < load-on-startup > 1 </ load-on-startup > 12 </ servlet > 13 < servlet > 14 < servlet-name > ServletLogin </ servlet-name > 15 < servlet-class > servlet.ServletLogin </ servlet-class > 16 </ servlet > 17 < servlet > 18 < servlet-name > ServletLogout </ servlet-name > 19 < servlet-class > servlet.ServletLogout </ servlet-class > 20 </ servlet > 21 22 < servlet-mapping > 23 < servlet-name > ServletWebInitializer </ servlet-name > 24 < url-pattern > /servlet/ServletWebInitializer </ url-pattern > 25 </ servlet-mapping > 26 < servlet-mapping > 27 < servlet-name > ServletLogin </ servlet-name > 28 < url-pattern > /servlet/ServletLogin </ url-pattern > 29 </ servlet-mapping > 30 < servlet-mapping > 31 < servlet-name > ServletLogout </ servlet-name > 32 < url-pattern > /servlet/ServletLogout </ url-pattern > 33 </ servlet-mapping > 34 < welcome-file-list > 35 < welcome-file > index.jsp </ welcome-file > 36 </ welcome-file-list > 37 </ web-app >

Web初始化：

1 public void init() throws ServletException { 2 // Put your code here 3 ServletContext app = this .getServletContext(); 4 app.setAttribute( " onlineMember " , new Integer( 0 )); // 在线会员人数 5 app.setAttribute( " onlineNumber " , new Integer( 0 )); // 当前在线人数 6 app.setAttribute( " totalNumber " , new Integer( 0 )); // 历史访问人数 7 }

Web监听器：

1 public class WebListener implements HttpSessionListener { 2 3 public WebListener() { 4 // TODO Auto-generated constructor stub 5 } 6 7 public void sessionCreated(HttpSessionEvent se) { 8 // TODO Auto-generated method stub 9 10 ServletContext app = se.getSession().getServletContext(); 11 int olCount = ((Integer)app.getAttribute( " onlineNumber " )).intValue(); 12 app.setAttribute( " onlineNumber " , olCount + 1 ); 13 14 int ttlCount = ((Integer)app.getAttribute( " totalNumber " )).intValue(); 15 app.setAttribute( " totalNumber " , ttlCount + 1 ); 16 } 17 18 public void sessionDestroyed(HttpSessionEvent se) { 19 // TODO Auto-generated method stub 20 ServletContext app = se.getSession().getServletContext(); 21 int olCount = ((Integer)app.getAttribute( " onlineNumber " )).intValue(); 22 app.setAttribute( " onlineNumber " , olCount - 1 ); 23 } 24 25 }

总结如下：

1. 如果要在Web应用中初始化一些值，那么可以采用在web.xml加入1个或者多个特殊的servlet，并设置对应的servlet配置：

<servlet> <servlet-name>ServletWebInitializer</servlet-name> <servlet-class>servlet.ServletWebInitializer</servlet-class> <load-on-startup>x</load-on-startup>（x>=1，顺序越小启动优先级越高) </servlet>

将要初始化的内容写在这些特殊的servlet的init()方法内：

public void init() throws ServletException

2. 如果在一个新会话的开始，或者一个会话的结束时要进行某些计算，比如统计在线人数，那么可以在web.xml加入1个或者多个监听器：

<listener> <listener-class>listener.WebListener</listener-class> </listener>

对应的计算放在sessionCreated和sessionDestroyed里面：

public class WebListener implements HttpSessionListener

public void sessionCreated(HttpSessionEvent se)

public void sessionDestroyed(HttpSessionEvent se)

3. mysql数据库采用jdbc连接的步骤如下：

// 建立数据库连接 Connection conn = DBUtil.getConnection(); // 定义查询语句 String sql = "select * from user where `username`=? and `password`=?"; PreparedStatement pstmt = conn.prepareStatement(sql); // 查询获得结果集 ResultSet rs = pstmt.executeQuery();

// 关闭结果集，查询语句，数据库连接 rs.close(); pstmt.close(); conn.close();

4. jsp页面除了少量的if语句，基本上都是输出语句，将数据计算放到对应的JavaBean或者控制器内部完成。

完整程序下载页面：http://u.115.com/file/f8930734df

转载于:https://www.cnblogs.com/nysanier/archive/2011/04/20/2022705.html

最新回复(0)

Jsp+Servlet+Tomcat+Mysql+JDBC+MVC模式 简单实用范例

Jsp+Servlet+Tomcat+Mysql+JDBC+MVC模式简单实用范例