http://wiki4.caucho.com/Java_EE_Tutorial_covering_JSP_2.2,_and_Servlets_3.0 This tutorial focuses on using Servlet's and JSP the right way. Servlet and JSP have evolved over the years, and now there is often more than one way to do things. For example, this tutorial uses EL and JSTL not JSP scriptlets, it uses JSPs in a Model 2/MVC style not in a model 1 style, etc. Consider it a tutorial that focuses only on the best practices and not the legacy ways to do things. There are other tutorials on this subject, but this tutorial is going to be different in that it is going to put all code into github, and you can follow along with Eclipse. Also instead of focusing on JSF, we are going to focus on JSP and Servlets as the main view technology. Java EE, JSP and Servlets have added a lot of features that are in other frameworks, making those other frameworks less relevant then they were before Java EE garnered these extra abilities. Even is you decide to use JSF, Struts, Stripes, Spring MVC, JSF, etc., this tutorial should help you have a better understanding of the JSP/Servlets core that they build on. We are going to start by building a simple bookstore. We will progressively add more features to the bookstore and as we do we will use more of Java EE/CDI, JSP and Servlets. For this tutorial, I am going to use Resin 4.0.x, but you could use any Java EE 6 Web Profile compliant application server.

1. Java
EE
Servlet/JSP
Tutorial
Second cookbook, getting started with Model 2: Servlet and JSP
Implementing the Edit/Update, Add
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2. Cookbook:
Intro
to
Serlvets
and
JSP
• This cookbook in the Java EE Servlet /JSP tutorial
covers building CRUD Operations in a Model 2
architecture
• This is a continuation of Building a simple listing in
JSP using Java EE and Servlets (Part 1).
• This
is
part
2,
must
do
part
1
first
• Part
1
Slides
• Covers
working
with
Servlet
doGet/doPost
methods,
JSTL,
redirec8on
versus
forwarding
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3. Redux:
About
tutorial
• Very
liNle
knowledge
of
HTML,
Java
and
JSP
is
assumed
• HTML
and
Java
not
covered
length,
but
pointers
in
the
right
direc8on
• Focus
is
Java
Servlets
and
JSP
(Java
Server
Pages)
• Use
whatever
IDE
you
would
like,
but
direc8ons
focus
on
Eclipse
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4. Redux:
App
you
are
building
Sorting
Remove
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5. Outline
• 1 Java EE Servlet Tutorial: Implementing a basic CRUD listing
• 2 Adding a link to the book listing to edit a book
• 2.1 Adding an edit book link to book-list.jsp listing
• 3 Adding a link to the book listing to add a book
• 3.1 Adding an add book link to book-list.jsp listing
• 4 Servlet doGet to load a Book form
• 4.1 BookEditorServlet.java doGet
• 4.2 BookEditorServlet.java doGet() delegate to book-form.jsp page
• 4.3 BookEditorServlet.java doGet() delegate to book-form.jsp page
• 5 Rendering the book form HTML
• 5.1 book-form.jsp Renders form to update or add a Book
• 5.2 book-form.jsp using JSTL c:choose to display update or add status
• 5.3 book-form.jsp using JSTL c:if to hidden id field for edit/update operation
• 6 Creating a doPost method to handle the form submission
• 6.1 BookEditorServlet.java doPost
• 7 Quick review of what we have so far
• 7.1 ./WebContent/WEB-INF/pages/book-form.jsp full listing
• 7.2 ./WebContent/WEB-INF/pages/book-list.jsp full listing
• 7.3 ./src/META-INF/beans.xml full listing
• 7.4 ./src/com/bookstore/Book.java
• 7.5 ./src/com/bookstore/BookRepositoryImpl.java full listing (testing only)
• 7.6 ./src/com/bookstore/BookRepository.java full listing
• 7.7 ./src/com/bookstore/web/BookEditorServlet.java
• 7.8 ./src/com/bookstore/web/BookListServlet.java
• 8 Technical debt
• 9 Cookbooks and Tutorials
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6. Where
we
leX
off
in
last
example
• BookListServlet
uses
a
BookRepository
object
(DAO)
to
load
a
list
of
books
• BookListServlet
then
delegated
to
book-­‐list.jsp
to
render
the
book
lis8ng
with
JSTL
and
Unified
EL
• In
this
cookbook,
• add
a
link
to
the
book
lis9ng
for
edi9ng
a
book
• add
a
link
so
that
the
end
user
can
add
a
new
book
to
the
lis9ng
• Create
backend
Servlets
to
handle
new
links
on
book
lis9ng
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7. Model
2
MVC
Model View Controller
•BookListingServlet
•Book •book-form.jsp •BookEditorServlet
•BookRepositoryImpl •book-list.jsp
•BookRepository
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8. Add
a
new
link
to
book-­‐lis8ng.jsp
• Add
link
to
edit
opera8on
• Edit
opera8on
pulls
up
form
with
details
of
Book
8tle
that
is
clicked
• Uses
<a
href=””
• Uses
expression
pageContext.request.contextPath/book
to
address
new
Edit
Servlet
• Servlet
created
later,
id
parameter
implies
edit
opertaion
• EL
expression
pageContext.request.contextPath
refers
to
the
URI,
web
app
(war
file)
is
mapped
to
in
Servlet
container
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9. Edit
Link
on
Title
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10. What
gets
rendered
• The
following
links
with
URI
(/bookstore)
of
webapp
get
rendered
when
book-­‐
lis8ng.jsp
loads
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11. Adding
a
“add
a
book”
link
to
book
lis8ng
• Now
that
links
are
going
to
URI
/book,
• You
need
a
Servlet
that
handles
links
• For
add
opera9on
and
edit
opera9on
• New
BookEditorServlet
will
handle
both
add
and
edit
book
func8ons
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12. Add
Link
Above
Table
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13. BookEditorServlet
• @WebServlet("/book")
maps
BookEditorServlet
to
the
URI
/
book
• Common
to
load
a
form
from
a
doGet
method,
and
to
handle
the
form
submission
via
doPost
• Follows
REST
and
HTTP
principles
GET
opera8ons
reads
data,
• later
POST
data
modifies
data
• doGet
method
uses
id
being
empty
or
not
to
• determine
if
this
is
a
load
"Add
Book
Form"
or
• load
"Update
Book
Form"
opera9on
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14. BookEditorServlet
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15. BookEditorServlet.doGet
loads
edit/add
form
Add Link
Edit Link
doGet is load form operation
book-form.jsp
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16. Model
2
and
BookEditorServlet.doGet
• In
Model
2,
Servlets
(controllers/ac8ons)
prepares
model
data
for
the
view
• This
includes
date
formagng
Notice “book” is mapped into request scope
“book” will get used from book-form.jsp
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17. Model
2
and
BookEditorServlet.doGet
(cont)
• To
render
the
HTML
form,
the
servlet
delegates
to
book-­‐form.jsp
book-form.jsp
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18. book-­‐form.jsp
(1
of
3)
• book-­‐form.jsp
renders
form
to
edit
book
• If
book.id
present
then
edit
opera8on,
otherwise
add
opera8on
• JSTL
c:choose,
c:otherwise
to
display
correct
9tle
based
on
Update
(Edit)
or
Add
opera9on
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19. book-­‐form.jsp
(2
of
3)
• Uses
Unified
EL
to
render
values
and
then
just
plain
HTML
for
form
fields
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20. book-­‐form.jsp
(3
of
3)
• hidden
id
property
is
rendered
if
edit
(Update)
opera8on
• Cancel
buNon
takes
them
back
to
lis8ng
(/book/
is
lis8ng).
• Submit
buNon
POST
form
to
BookEditorServlet.doPost
(defined
next)
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21. BookEditorServlet.doPost()
• if
id
request
parameter
is
null
then
BookEditorServlet.doPost
calls
bookRepo.addBook,
• otherwise
it
calls
bookRepo.updateBook
•
Then,
doPost
redirects
to
/book/
• redirect
means
an
extra
hit
to
the
server,
• basically
telling
browser
to
load
another
link
• Not
forward
like
before
because
of
bookmarking
• Remember
URL
/book/
(ending
in
slash)
represents
a
collec9on
of
books,
while
/book
(no
slash)
represents
a
single
book
• If
doPost
did
a
forward,
then
browser
would
show
wrong
link
for
lis9ng
• Use
sendRedirect
instead
of
a
forward
for
bookmarking
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22. BookEditorServlet.doPost()
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23. BookEditorServlet.doPost
book-form.jsp
BookListServlet
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24. Review
of
CRUD
lis8ng
• Book
Form
• Servlet
that
loads
Book
(doGet)
form
• ./WebContent/WEB-­‐INF/pages/book-­‐form.jsp
and
handles
Book
form
submissions
(doPost).
• Book
Lis8ng
• ./WebContent/WEB-­‐INF/pages/book-­‐list.jsp
./src/com/bookstore/web/
BookEditorServlet.java
• Needed
for
Java
EE
dependency
injec8on
(CDI)
• ./src/META-­‐INF/beans.xml
• Servlet
that
looks
up
a
list
of
books
and
displays
the
lis8ng
• Domain/model
object
./src/com/bookstore/web/
• ./src/com/bookstore/Book.java
BookListServlet.java
• Repository
implementa8on
using
Java
collec8ons
(just
for
tes8ng)
• ./src/com/bookstore/BookRepositoryImpl.java
• Interface
to
Book
Repository
so
we
can
swap
it
out
with
JDBC,
JPA,
JCache
and
MongoDB
version
later
• ./src/com/bookstore/BookRepository.java
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