Transcript ECE356 - Databases - University of Waterloo

ECE356 – Database Systems
Lab 1 – Building a Web Project with
NetBeans
Tiuley Alguindigue
Lab Instructor – University of Waterloo, E & CE Dept.
Fall 2013
Lab 1 - Learning objectives
1.
2.
3.
4.
5.
6.
7.
Starting NetBeans
Creating a Web project
Adding JSPs, servlets, and beans to a project
Model-View-Controller architecture
Using JSPs and beans to process HTML forms
Adding MySQL JDBC driver to project
Connecting to MySQL from a bean
Starting NetBeans
• Install Netbeans 7.2.1
– http://netbeans.org/downloads/
– Download the “Java EE option” from the available
“NetBeans IDE Download Bundles”.
– Select the “Apache Tomcat” option for your web
server during the installation.
Starting NetBeans
• For lab computers
– NetBeans is installed with the Glassfish option
– Make sure the environment variable JAVA_HOME
is set to the directory where the JDK is installed
(under C:\Program Files\Java\ )
Note: The procedure for setting JAVA_HOME on a Windows box is to
right click on "My Computer", select Properties, Advanced (or
Advanced System Settings), Environment Variables, and then either
Edit or New.
Starting NetBeans
• Create a Web Project
– File/New Project
Create a Web Project
Create a Web Project
Create a Web Project
Create a Web Project
Create a Web Project
• Run your first Web Project
• Displays a web page with “Hello World!”
Adding JSPs, servlets, and beans to a
project
• Modify this web project so that:
– It will allow the user to enter some data in
another JSP.
– It will execute a servlet that will connect to a
MySQL database running in the eceweb server.
– It will use java classes to store data entered by
the user and also to store the status of the
connection with the database as required by the
Model-View-Controller architecture.
Adding JSP
• Add a JSP called user_data_form.jsp under
the folder “Web Pages”
• Add html commands to create a form such as
the one shown in the next slide.
• Use the following command when specifying
your form html tag:
<form method="post" action="UserDataServlet">
Note: UserDataServlet is a servlet that you will build in the next step of
this lab.
Adding JSP
Adding JSP
• Modify index.jsp to allow the user to access
the page that you have just created. After
your changes index.jsp must contain code to
display the page shown in the next slide.
Your first JSP
index.jsp
Adding a Servlet
• Test your web project
• You will now add the servlet
UserDataServlet.java which defines the action
performed when the user clicks on the
“submit” button of your form.
Add a new package
Add servlet under this package
Add servlet under this package
Add servlet under this package
UserDataServlet.java
Uses a class called UserData ( called a JavaBean) to store the values entered in the form. We have
provided this class here.
The java code in this servlet will:
1. Get the parameters entered in the form and store them in the corresponding fields in object
of type UserData.
Hint: see documentation for class HttpServletRequest, method getParameter()
2. Save the object UserData to the session request
Hint: see documentation for class HttpSession , method setAttribute()
3. Display the values entered in the form using a jsp called user_data_thanks.jsp (provided here)
Hint: see documentation for getServletContext().getRequestDispatcher(..).forward(..);
Testing your jsps, forms and servlet
• Add the user_data_thanks.jsp (provided here)
to the folder ‘Web Pages”
• Add the user_data_thanks2.jsp (provided
here) to the folder ‘Web Pages”
• Add the UserData.java class (provided here) to
the source package “ece356”
• Test your web project
Testing your jsps, forms and servlet
user_data_thanks.jsp
Testing your jsps, forms and servlet
user_data_thanks2.jsp
Model-View-Controller architecture
• Your web project uses the MVC software
architecture model:
– JSP to receive and present data to the user (View)
– Servlet to implement navigation and business
logic (Controller)
– JavaBean – use to encapsulate related properties
in a single java object (Model)
– Data Access Object (DAO) - object that provides
an abstract interface to a database(Model)
Adding MySQL JDBC driver to project
• The next part of this lab is to add an option to
connect to the MySQL database in the server
• MySQL provides connectivity for client
applications developed in the Java
programming language through a JDBC driver,
which is called MySQL Connector/J.
• You will need to add to your web project the
library for the MySQL Connector/J
Adding MySQL JDBC driver to project
Add a new Library, select the “MySQL JDBC Driver” from the list of available libraries
MySQL JDBC driver added to project
Your “Projects” tab should now show the MySQL JDBC Driver jar file.
Add option to connect to the MySQL
database in the server
• Modify index.jsp:
– Add a link that allows the user to connect to the
database
– When this link is clicked, your web application will
execute the servlet DBTestServlet.java (you will
write this servlet in the next part of this lab)
– Next slide shows index.jsp after these
modifications
Your first page
index.jsp
Add a new Servlet DBTestServlet.java
• Add a new Servlet to package ece356 named
DBTestServlet.java. Make sure to choose the
option “Add information to deployment
descriptor (web.xml)” on the second panel.
• You will later edit this servlet and add the java
code needed to connect to the DB as part of
the method processRequest()
UserDBAO.java
• Servlet DBTestServlet uses the services of a data access
object(DAO) called to UserDBAO.java to interact with the
database. The code for UserDBAO.java is provided here.
• Modify the method TestConnection() in the UserDBAO.java
so that the database, user id, and password corresponds to
your course database in the eceweb server. Ie. If your uw
userid is pthomas, your parameters should look as follows:
public static final String url =
"jdbc:mysql://eceweb.uwaterloo.ca:3306/";
public static final String user = “user_pthomas";
public static final String pwd = “your_password"; // specify your
password here, initially same as userid
DBTestServlet
processRequest()
• Modify method processRequest() in
DBTestServlet.java to connect to the database.
– Add call to TestConnection method in
UserDBAO.java:
UserDBAO.testConnection();
– The statement above may throw an exception
when the attempt to connect is not successful.
Your code should handle this exception.
DBTestServlet
processRequest()
• Handling exceptions – setting the value of variable with
name of jsp to be displayed:
String url;
try {
// Call static method using class name
UserDBAO.testConnection();
// Set the name of jsp to be displayed if
// connection succeds
url = "/dbtest.jsp";
} catch (Exception e) {
// Save the exception info in th e request object so it can be displayed.
request.setAttribute("exception", e);
// Set the name of jsp to be displayed if
// connection fails
url = "/error.jsp";
}
DBTestServlet
processRequest()
Displaying the suitable jsp from the servlet
(name of jsp is now stored in variable “url”):
getServletContext().getRequestDispatcher(url).forward(request, response);
Adding jsps displayed after connection
when connection is successful
• Add jsp name dbtest.jsp
Adding jsp displayed after connection
when connection is not successful
• Add jsp name error.jsp
Adding jsps displayed after connection
• Add jsp name error.jsp (provided here)
– Use request.getAttribute() to get the value of
attribute “exception” (this attribute was saved to
the response object in DBTestServlet)
– Prints error message and stack trace in this
attribute
Summary
What we have learned:
• Created a Web project with NetBeans
• The project, using Model-View-Controller
architecture, demonstrates how to:
– Use JSPs and a HTML form to collect data from the
user.
– Use a JavaBean class to represent user data.
– Store and Access data from JavaBean in JSPs and
servlets.
– Connect to a database from a servlet, using a DAO
object to interface with the database.
Further self study
•
•
•
•
Java Programming
HTML
JSP Programming
Model View Controller(MVC) architectural
pattern as it applies to JSP programming
References
Sample Code for this lab was written by Prof. Wojciech
Golab
Java, JSP and JDBC
The Java Tutorials
The Java Tutorial - Trail: JDBC(TM) Database Access
Introduction to Java Server Pages(JSP)
Web Application Development
The Java EE 6 Tutorial
Tutorial - Creating a Simple Web Application Using a MySQL
Database (using NetBeans)
References
• Reference for html
www.w3schools.com
• Reference for MVC and JSPs:
http://netbeans.org/kb/docs/javaee/ecommerce/de
sign.html?print=yes
• Ref for DAO :
http://en.wikipedia.org/wiki/Data_access_object