Transcript powerpoint document

The J2EE BookShop
A detailed walk through of the J2EE
BookShop
Functional Requirements - repetition
The Bookshop is a web shop where the
customer can do the following
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Customers should log into the system
Customers should be able to browse through all
available books
Customers should be able to view detailed
information about a particular book
Functional Requirments - repetition
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Customers should be able to add and remove
books from their shopping cart
When customers want to checkout their order,
they should supply shipping information
When checking out, the order should be written in
the ORDER table and the different books in the
ORDER_ITEMS table
Technical Requirments - repetition
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Use MVC, Model View Controller
The result return from beans or servlet should
be XML that’s transformed to HTML with
XSLT (use the JSTL tag library). Never print
HTML in the beans or the Servlets. Output in
JSPs are acceptable
Try use a Custom tag, for example to return
the shopping cart
Fundamental design ideas
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The book shop uses these fundamental
design ideas
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Model View Controller (MVC) is used as the base
All requests should be handled by a single
controller servlet
Standard J2EE Security is used to secure the site
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We don’t implement the security, we only tell the system
to use it
All dynamic content should be returned to the
view as XML
All XML is transformed into XHTML with XSLT
Fundamental design ideas
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Static layout can be performed in the JSP
pages for simplicity
Only control logic in the controller servlet
All business logic in Java Beans
All presentation logic in JSPs and XSLT
The shopping cart is accessed through a
Custom Tag
Fundamental design ideas
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Environment variables (like JDBC Url and the
different JSP pages) should be configurable
at deploy time, i.e. should be defined in
web.xml
web.xml
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One servlet
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Named Shop and mapped as /shop
se.upright.education.uu.pvk.assignmenttwo.servle
ts.ShopServlet
Five init-param entries
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JDBC_URL
CHECKOUT_PAGE
SHOW_PAGE
THANKYOU_PAGEDETAIL_PAGE
web.xml
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Three Tag Libraries
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JSTL – core
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JSTL – xml
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c.tld
x.tld
BookShop
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bookshop.tld
web.xml
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The URL-pattern /* is secured
Only users in the role tomcat is allowed
Form-login is used
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login.jsp is the login form
login_error.jsp is the error page in case of a login
failure
web.xml
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<security-constraint>
<web-resource-collection>
<web-resource-name>TheShop</web-resource-name>
<url-pattern>/*</url-pattern>
</web-resource-collection>
<auth-constraint>
<role-name>tomcat</role-name>
</auth-constraint>
<user-data-constraint>
<transport-guarantee>NONE</transport-guarantee>
</user-data-constraint>
</security-constraint>
<login-config>
<auth-method>FORM</auth-method>
<form-login-config>
<form-login-page>/login.jsp</form-login-page>
<form-error-page>/login_error.jsp</form-error-page>
</form-login-config>
</login-config>
Database access
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All database access is handled by two beans
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BookListBean
OrderBean
The book list is only fetched once and then
added to the application context
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Bad performance to get the list for each request
Unnecessary memory usage if each user have a
book list of their own
Read-only data
BookBean
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A JavaBean that represent one book
All properties of the book available with
getXXX() and setXXX() methods
getXml() returns the book in XML format
BookListBean
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The implementation of the book list
A Collection with BookBeans is the actual list
When created, the BookListBean() connects
to the database and fetches all books
getXml() returns the entire book list as XML
getXml() uses BookBean.getXml() to build it’s
XML representation
ShoppingBean
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The implementation of the shopping cart
Each user should have his own instance of
the shopping cart
addBook(book, quantity) adds a book to the
cart
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If the exists in the cart, only increase the quantity
removeBook(id, quantity) removes a book
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If the quantity to remove is more or equal to the
present, remove the book, otherwise decrease the
quantity in the cart
ShoppingBean
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getCart() returns the Collection that holds the
actual cart
getXml() returns the shopping cart as XML
clear() removes all books from the cart
OrderBean
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Used to create a new order based on the shopping
cart and the shipping information entered by the
user
The order is written to the ORDER-table
The different books are written to the ORDER_ITEM
table
Explicit transaction handling is used
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Inserting an order is one operation
Each book is one operation
All operations in one transaction, i.e. write the order and all
books, or write nothing
ShopingCartTag
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The implementation of the Custom tag to
output the shopping cart
Uses ShoppingBean.getXml() to get the cart
XML – the book
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<book>
<id>1</id>
<title>Javaprogramming</title>
<authorname>Fredrik</authorname>
<authorsurname>Alund</authorsurname>
<price>23</price>
<pages>234</pages>
<description>Bla bla bla</description>
</book>
XML – the book list
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<booklist>
<book>
<id>1</id>
<title>Javaprogramming</title>
<authorname>Fredrik</authorname>
<authorsurname>Alund</authorsurname>
<price>23</price>
<pages>234</pages>
<description>Bla bla bla</description>
</book>
<book>
<id>2</id>
<title>Javaprogramming2</title>
<authorname>Kalle</authorname>
<authorsurname>Svensson</authorsurname>
<price>234</price>
<pages>100</pages>
<description>Bla bla bla</description>
</book>
</booklist>
XSL files
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booklist_xsl.xslt
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bookdetail_xsl.xslt
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Format the details about a particular book
BookBean.getXml()
shoppingcart_xsl.xslt
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Format the book list
BookListBean.getXml()
The shopping cart shown in the show page
ShoppingBean.getXml()
shoppingcart_checkout_xsl.xslt
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The shopping cart shown in the checkout page
ShoppingBean.getXml()