架構實例之Demo_JSP_JavaBean
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_JavaBean實現功能
用戶登錄、用戶注冊、退出登錄。
3、Demo_JSP_Java_Bean使用技術
本實例使用了JSP、JavaBean和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_Java_Bean系統架構圖
下面請看圖二（系統中JSP與JavaBean之間的邏輯關系圖）：
圖二：系統中JSP與JavaBean之間的邏輯關系圖
4、具體實現
（1）在MyEclipse中新建一個Web project項目，並命名為Demo_JSP_JavaBean；
（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JavaBean文件和JSP文件（PS：其中JSP文件代碼此處只貼出部分代碼，其他JSP文件代碼請參考本人上一篇博客哦(鏈接地址：http://www.cnblogs.com/liuzhen1995/p/5700409.html)）：
1)創建Java類DBAccess，包名取為liu，該類實現數據庫登錄連接的功能，具體代碼如下：
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）在上一步中創建的包下，再創建一個Java類UserBean，該類實現數據庫查詢和寫入功能，具體代碼如下：
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，接受login.jsp頁面中用戶輸入的用戶名和密碼，通過調用JavaBean實現登錄認證，具體代碼如下：
<%@ 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，通過調用JavaBean實現注冊，並把數據寫入數據庫，具體代碼如下：
<%@ 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、運行結果展示
具體運行結果請參考本人上一篇博客哦，運行結果是一模一樣的（鏈接地址：http://www.cnblogs.com/liuzhen1995/p/5700409.html）~~~
附：Demo_JSP_JavaBean項目源碼文件百度雲下載鏈接：http://pan.baidu.com/s/1sl1nd9r 密碼：lrdk； 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
