Dynamic generation page (Dynamically Retrieve data information from the database), Database Dynamic

Dynamic generation page (Dynamically Retrieve data information from the database), Database Dynamic

The course design is a little annoying, so I simply wrote the following code to dynamically display the products added to the shopping cart to the front-end page.

The first is my head. jsp. The "My directory" here uses a servlet name named "selectUserCart" instead of a direct link.

The user, books, and userAccout classes used in my project basically record the basic information and implement the setXxx () and getXxx () methods.

<% @ 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"> 
Then there are two classes I have used:
Search for the tool class of my shopping cart: myCartUtil. java
<Pre name = "code" class = "java"> package myCart; import java. SQL. connection; import java. SQL. preparedStatement; import java. SQL. resultSet; import java. SQL. SQLException; import java. util. arrayList; import bookConnUtil. DBUtil; import bookConnUtil. books; public class myCartUtil {public static ArrayList <mycart> list = new ArrayList <mycart> (); public static ArrayList <books> booklist = new ArrayList <books> (); public Static String msg; public static int countbook = 0; // public static mycart [] cart = new mycart [10]; public static int count = 0; public static boolean insertIntoMyCart (String username, String bookname, String pianduanName) throws SQLException {String cartInsert = "insert into userAccount valus (?,?,?) "; Boolean flag = false; Connection conn = null; PreparedStatement stmt = null; try {conn = DBUtil. getConnection (DBUtil. CONNECTION_ SQL); stmt = conn. prepareStatement (cartInsert); stmt. setString (1, username); stmt. setString (2, bookname); stmt. setString (3, pianduanName); int count = stmt.exe cuteUpdate (); if (count> 0) {flag = true;} else {flag = false;} catch (Exception e) {System. out. println ("sorry, your program failed"); e. printStackTrac E ();} finally {conn. close (); stmt. close ();} return flag;} public static boolean selectUserCart (String userName) throws SQLException {boolean flag = false; String cartSelect = "select username, bookname, pianduanName, imagePath, price from userAccount where username =? "; Connection conn = null; ResultSet rs = null; PreparedStatement stmt = null; try {conn = DBUtil. getConnection (DBUtil. CONNECTION_ SQL); stmt = conn. prepareStatement (cartSelect); stmt. setString (1, userName); rs = stmt.exe cuteQuery (); while (rs. next () {mycart cart = new mycart (); cart. setUserName (rs. getString (1); cart. setBookName (rs. getString (2); cart. setPianduanName (rs. getString (3); cart. setImagePath (rs. getString (4); cart. setPrice (rs. getInt (5); list. add (cart); count ++;} System. out. println ("++" + count + "++ "); if (count = 0) {msg = "null";} else {msg = "full";} flag = true;} catch (Exception e) {System. out. println ("sorry, your program failed"); e. printStackTrace ();} finally {conn. close (); stmt. close ();} return flag;} public static boolean selectAllBooks () throws SQLException {boolean flag = false; String cartSelect = "select bookId, bookName, pianduanName, imagesPath, price from books "; Connection conn = null; ResultSet rs = null; PreparedStatement stmt = null; try {conn = DBUtil. getConnection (DBUtil. CONNECTION_ SQL); stmt = conn. prepareStatement (cartSelect); rs = stmt.exe cuteQuery (); while (rs. next () {books book = new books (); book. setBookID (rs. getString (1); book. setBookName (rs. getString (2); book. setPianduanName (rs. getString (3); book. setImagePath (rs. getString (4); book. setPrice (rs. getInt (5); booklist. add (book );
<Span style = "white-space: pre "> </span> // I am not doing well, so I want to use this mark to do better. Please implement countbook ++ on your own;} System. out. println ("++" + count + "++ "); if (count = 0) {msg = "null";} else {msg = "full";} flag = true;} catch (Exception e) {System. out. println ("sorry, your program failed"); e. printStackTrace ();} finally {conn. close (); stmt. close () ;}return flag ;}}

The following is the database connection class:


<Pre name = "code" class = "java"> package bookConnUtil; import java. SQL. connection; import java. SQL. driverManager; import java. SQL. SQLException; public class DBUtil {public static final int CONNECTION_MYSQL = 2; public static final int CONNECTION_ SQL = 1; public static final int CONNECTION_ODBC = 0; public DBUtil () {} public static Connection getConnection (int connection_type) throws Exception {switch (connection_type) {Case CONNECTION_ODBC: return getConnectionODBC (); case CONNECTION_ SQL: return getConnectionSQL (); case CONNECTION_MYSQL: return getConnectionMYSQL ();} return null ;} /***** ������������/private static Connection getConnectionODBC () throws Exception {Connection conn = null; try {Class. forName ("sun. jdbc. odbc. jdbcOdbcDriver "); System. out. println ("abc"); conn = DriverManager. getConnection ("jdbc: odbc: mybook", "sa", "123" ); System. out. println ("connection successful");} catch (Exception e) {e. printStackTrace (); throw e;} return conn;} private static Connection getConnectionSQL () throws Exception {Connection conn = null; String connectionUrl = "jdbc: sqlserver: // localhost: 1433; databaseName = user; "; try {Class. forName ("com. microsoft. sqlserver. jdbc. SQLServerDriver "); conn = DriverManager. getConnection (connectionUrl, "sa", "123"); System. out. println ("connection successful" );} Catch (Exception e) {e. printStackTrace (); throw e;} return conn;} private static Connection getConnectionMYSQL () throws Exception {String connectionUrl = "jdbc: mysql: // localhost: 3306/user "; string username = "root"; String password = "mysql"; Connection conn = null; try {Class. forName ("com. mysql. jdbc. driver "); conn = DriverManager. getConnection (connectionUrl, username, password); System. out. println ("connection successful ");} Catch (Exception e) {e. printStackTrace (); throw e;} return conn;} public static void close (Connection conn) throws Exception {if (conn! = Null) {try {conn. close () ;}catch (SQLException e) {e. printStackTrace (); throw e ;}}}}

The following shows the user shopping cart search class:

<Pre name = "code" class = "java"> package myCart; import java. io. IOException; import java. SQL. SQLException; import javax. servlet. servletException; import javax. servlet. http. httpServlet; import javax. servlet. http. httpServletRequest; import javax. servlet. http. httpServletResponse; import javax. servlet. http. httpSession; import bookConnUtil. bookDAO; public class selectUserCart extends HttpServlet {/*****/private static final long serialVersionUID = 1L; public int count = myCartUtil. count; protected void doGet (HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stubHttpSession session = req. getSession (); String username = (String) session. getAttribute ("username"); try {// System. out. println ("the query process has not been executed here"); boolean flag = myCartUtil. selectUserCart (username); if (flag = true) {/* for (mycart message: myCartUtil. list) {for (int I = 0; I <3; I ++) {String A = message. getUserName () ;}} * // session. setAttribute ("count", countNum); if (myCartUtil. msg. equals ("null") {session. setAttribute ("null", myCartUtil. msg);} else {session. setAttribute ("full", myCartUtil. msg);} req. getRequestDispatcher ("selectMyAcccount. jsp "). forward (req, resp);} else {req. getRequestDispatcher ("error.html "). forward (req, resp) ;}} catch (SQLException e) {// TODO Auto-generated catch blocke. printStackTrace ();}}}

My directory implementation code:

<Pre name = "code" class = "html"> <% @ 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"> 








 
Copyright Disclaimer: This article is an original article by the blogger and cannot be reproduced without the permission of the blogger.