架构实例之Demo_JSP_JavaBean
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_JavaBean实现功能
用户登录、用户注册、退出登录。
3、Demo_JSP_Java_Bean使用技术
本实例使用了JSP、JavaBean和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_Java_Bean系统架构图
下面请看图二（系统中JSP与JavaBean之间的逻辑关系图）：
图二：系统中JSP与JavaBean之间的逻辑关系图
4、具体实现
（1）在MyEclipse中新建一个Web project项目，并命名为Demo_JSP_JavaBean；
（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：http://pan.baidu.com/s/1i5psdDF 密码：meyg
（3）在Demo_JSP项目中新建以下JavaBean文件和JSP文件（PS：其中JSP文件代码此处只贴出部分代码，其他JSP文件代码请参考本人上一篇博客哦(链接地址：http://www.cnblogs.com/liuzhen1995/p/5700409.html)）：
1)创建Java类DBAccess，包名取为liu，该类实现数据库登录连接的功能，具体代码如下：
package liu; import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement; public class DBAccess { private String drv = "com.mysql.jdbc.Driver"; private String url = "jdbc:mysql://localhost:3306/library_system"; private String usr = "root"; private String pwd = "root"; private Connection conn = null; private Statement stm = null; private ResultSet rs = null; public boolean createConn() {
boolean b = false;
try {
Class.forName(drv).newInstance();
conn = DriverManager.getConnection(url, usr, pwd);
b = true;
} catch (SQLException e) {
} catch (ClassNotFoundException e) {
} catch (InstantiationException e) {
} catch (IllegalAccessException e) {
}
return b;
} public boolean update(String sql) {
boolean b = false;
try {
stm = conn.createStatement();
stm.execute(sql);
b = true;
} catch (Exception e) {
System.out.println(e.toString());
}
return b;
} public void query(String sql) {
try {
stm = conn.createStatement();
rs = stm.executeQuery(sql);
} catch (Exception e) {
}
} public boolean next() {
boolean b = false;
try {
if(rs.next())b = true;
} catch (Exception e) {
}
return b;
} public String getValue(String field) {
String value = null;
try {
if(rs!=null)value = rs.getString(field);
} catch (Exception e) {
}
return value;
} public void closeConn() {
try {
if (conn != null)
conn.close();
} catch (SQLException e) {
}
} public void closeStm() {
try {
if (stm != null)
stm.close();
} catch (SQLException e) {
}
} public void closeRs() {
try {
if (rs != null)
rs.close();
} catch (SQLException e) {
}
} public Connection getConn() {
return conn;
} public void setConn(Connection conn) {
this.conn = conn;
} public String getDrv() {
return drv;
} public void setDrv(String drv) {
this.drv = drv;
} public String getPwd() {
return pwd;
} public void setPwd(String pwd) {
this.pwd = pwd;
} public ResultSet getRs() {
return rs;
} public void setRs(ResultSet rs) {
this.rs = rs;
} public Statement getStm() {
return stm;
} public void setStm(Statement stm) {
this.stm = stm;
} public String getUrl() {
return url;
} public void setUrl(String url) {
this.url = url;
} public String getUsr() {
return usr;
} public void setUsr(String usr) {
this.usr = usr;
}
}
2）在上一步中创建的包下，再创建一个Java类UserBean，该类实现数据库查询和写入功能，具体代码如下：
package liu;
public class UserBean {
public boolean valid(String username, String password) {
boolean isValid = false;
DBAccess db = new DBAccess();
if(db.createConn()) {
String sql = "select * from userInfo where username='"+username+"' and password='"+password+"'";
db.query(sql);
if(db.next()) {
isValid = true;
}
db.closeRs();
db.closeStm();
db.closeConn();
}
return isValid;
}
public boolean isExist(String username) {
boolean isExist = false;
DBAccess db = new DBAccess();
if(db.createConn()) {
String sql = "select * from userInfo where username='"+username+"'";
db.query(sql);
if(db.next()) {
isExist = true;
}
db.closeRs();
db.closeStm();
db.closeConn();
}
return isExist;
}
public void add(String username, String password, String email) {
DBAccess db = new DBAccess();
if(db.createConn()) {
String sql = "insert into userInfo(username,password,mail) values('"+username+"','"+password+"','"+email+"')";
db.update(sql);
db.closeStm();
db.closeConn();
}
}
}
3）login_action.jsp，接收login.jsp页面中用户输入的用户名和密码，通过调用JavaBean实现登录认证，具体代码如下：
<%@ page import="liu.UserBean" %>
<%
//get parameters
String username = request.getParameter("username");
String password = request.getParameter("password"); //check null
if (username == null || password == null) {
response.sendRedirect("login.jsp");
} //validate
UserBean userBean = new UserBean();
boolean isValid = userBean.valid(username, password); 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>
4）register_action.jsp，通过调用JavaBean实现注册，并把数据写入数据库，具体代码如下：
<%@ page import="liu.UserBean" %>
<%
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
UserBean userBean = new UserBean();
boolean isExist = userBean.isExist(username);
if(!isExist) {
userBean.add(username, password1, email);
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
具体运行结果请参考本人上一篇博客哦，运行结果是一模一样的（链接地址：http://www.cnblogs.com/liuzhen1995/p/5700409.html）~~~
附：Demo_JSP_JavaBean项目源码文件百度云下载链接：http://pan.baidu.com/s/1sl1nd9r 密码：lrdk； 本实例所使用数据库建表sql语句文件下载链接：http://pan.baidu.com/s/1eS0n9aM 密码：7ttd