Original PDF Flash format microsoft-powerpoint---cf_and_jsp1-robi  


Microsoft Powerpoint Cf_and_jsp1 Robi

CF and JSP/Servlets
Developed originally by Robi Sen
For the CF UnderGround II Seminar, Apr 2001
Edited and enhanced by Charlie Arehart
(Robi had an emergency and couldn’t make it)
Topics Covered
! Overview JSP/Servlets
! Comparison of CF and JSP Tags
! Variables
! Application Scope
! Conditional Processing
! Reusing Common Code
! Sessions
! Database Access
! JSP/Servlet Engine, Tool Vendors
! Leveraging Java in CF Today
! Learning More
What are they?
! JSP/Java Servlets
! Servlets
! Comparable to CGI/ISAPI/NSAPI programming, in Java vs
Perl
! Java class that dynamically extends the function of a Web
Server
! Handle HTTP requests and generate HTTP responses
! JSP
! Tag-based scripting and page-template interface to Java
development, a la CF
! High level abstraction language to servlet standard
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Server
Process
for JSP
What CF has over JSP
! ColdFusion offers:
! Faster learning curve
! More features in language out of the box
! (i.e. cftransaction, cfhttp, cfftp, cached queries,
queries of queries)
! Greater abstraction, high productivity
! Greater maturity as web application
What JSP over CF
! JSP offers:
! Platform Agnostic(Write Once Run Anywhere)
! Scalability and Robustness
! Performance and power
! Access to Enterprise Technologies
! Manageability
! Standardization
! Massive adoption and developer community
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JSP VS CF
! As well as:
! Greater acceptance
! Better reputation
! More developer resources
! And being based on Java
! Object oriented
! Many libraries
Underlying JSP/Servlets is Java
! Not really appropriate to see JSP as “just an
alternative scripting environment”
! Yes, pretty easy to compare simple things
! Really need to understand Java to use effectively
! And to fully leverage the power it brings
! Underlying JSP is servlets
! Some things easier to do in one or the other
! JSP generally favored when creating lots of HTML
on a page
! JSP can be seen as your entrée to servlets
Exploring JSP vs. CF Tags
! CF
! Begin with CF (e.g., <CFOUTPUT>)
! Most have closing tags (e.g.,
<CFOUTPUT>HTML code</CFOUTPUT>
! JSP
! Begin with <% and end with %>
! Contain Java code, expressions, directives,
etc.
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CF Tags vs. JSP Tags
! May help to consider comparing CF and JSP for
performing common tasks
! <CFSET> ≅ <%! %>
! <CFSCRIPT> ≅ <% %>
! <CFOUTPUT> ≅ <%= %>
! <%@ %>
! <CFCONTENT> (set the output MIME type) vs <%@ page
contentType=“text/xml” %>
! <CFAPPLICATION> (turn on session-state management)
Where Files Are Stored
! Will depend on Java App Server
! I’m using Jrun, which supports multiple
servers, and multiple applications—doing
demo in “Demo” server
! Files stored at:
! D:\Program Files\Allaire\JRun\servers\default\demo-app\jsp
! JRUN sets up web server mapping to find files at:
! http://localhost:8100/demo/jsp/filename.jsp
! Have set up mapping in Studio to enable browse
Variables
! Variable Type (string, integer, etc.)
! Type-less in ColdFusion
! Strongly typed in JAVA
! Case Sensitivity
! Ignored in CF
! Enforced in JSP
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Defining Variables
! CF
<CFSET firstName=“John”>
<CFOUTPUT>Hello
#firstName#</CFOUTPUT>
! JSP
<%! String firstName = “John”; %>
Hello <%= firstName %>
Defining Variables
! Can also perform “pure” java statements
within JSP, as a “scriptlet”
! which can be useful in some situations
! though not particularly so, here
<% String fName = "John";
out.println("Hello " + fName); %>
Conditional Processing
! <CFIF>
<CFIF expression>
HTML and CFML tags executed if expression is true
<CFELSE>
HTML and CFML tags executed if expression is false
</CFIF>
! if/else in pure Java (servlet, class,
scriptlet)
<% if(expression) {
// Java code to execute if expression is true
} else {
// Java code to execute if expression is false
} %>
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Conditional Processing
! if/else in JSP
<% if(expression) { %>
HTML and JSP tags executed if expression is true
<% } else { %>
HTML and JSP tags executed if expression is false
<% } %>
Conditional Processing
! Conditional Expressions in CF/JSP
! Really about CF vs Java expressions,
as in:
! IS vs == or .equals()
! IS NOT vs !=
Conditional Processing
! <CFLOOP>
<CFLOOP FROM=“1” TO=“10” INDEX=“i”>
<CFOUTPUT>#i#</CFOUTPUT><BR>
</CFLOOP>
! “for” loop in pure Java
<% for(int i=1; i<=10; i++) {
out.println(i + “<BR>”);
} %>
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Conditional Processing
! “for” loop in JSP
<% for(int i=1; i<=10; i++) { %>
<%= i %><BR>
<% } %>
Reusing Common Code
! CF
! <CFINCLUDE TEMPLATE=“/Templates/header.cfm”>
! JSP
! <%@ include file = "path" ... %>
! or
! <jsp:include page=“/Templates/header.jsp”/>
! More like CF custom tag call
! Goes to other page, executes, and returns
! Passes request object to called page
Redirection
! CF
! <CFLOCATION URL=“/Forms/demo.cfm”>
! Java
!
<% RequestDispatcher aDispatcher =
request.getRequestDispatcher(“/Templates/hea
der.jsp”);
! aDispatcher.include(request, response); %>
! JSP
<jsp:forward page="/Forms/demo.cfm" />
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Comments
! CF
! <!--- comment --->
! Java
!
<% // one line comment;
/* multi
line comment */;%>
! JSP
<%-- comment --%>
Session State Maintenance
! CF
! Cookies
! Application.cfm
! Application variables
! Session variables
Application Scope
! Application Variable
! Shared among all users of application
<CFSET Application.myVariable=“somevalue”>
#Application.myVariable#
! Application object in JSP
! Shared among all users of application
<% application.setAttribute(“myVariable”,
“somevalue”);
out.println(application.getAttribute(“myVariable”)
); %>
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Application Scope
! ServletContext object
! Shared among all users of servlet
<%
getServletContext().setAttribute(“myVar
iable”, “somevalue”);
getServletContext().getAttribute(“myVaria
ble”); %>
Session State Maintenance
! CF “session.” variables
<cfset session.name = “john doe”>
! Servlet HttpSession object
<% HttpSession aSession = request.getSession();
aSession.setAttribute(“name”, “John Doe”); %>
! JSP session object is an instance of the
HttpSession object.
<% session.setAttribute(“name”, “John Doe”);%>
Database Access
! ODBC
! Standard database access method
! Inserts a middle layer (driver) between the
database and the application
! JDBC (Java Database Connectivity)
! Based on ODBC
! Allows access to any tabular data source from
the Java programming language
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Database Access: In CF
! Use CF Administrator to set the DataSource
! Query the database using <CFQUERY>
<CFSET variables.anID = 2>
<CFQUERY NAME=“myquery”
DATASOURCE=“mydatabase”>
select firstname, lastname from mytable
where id = #variables.anID#</CFQUERY>
! Accessing the data from the ResultSet
#myquery.firstname#
#myquery.lastname#
Database Access: In CF
! Displaying the ResultSet
! One Row
<CFOUTPUT>
The name is #myquery.firstname#
#myquery.lastname#
</CFOUTPUT>
! Many Rows
<CFOUTPUT QUERY=“myquery”>
The name is #myquery.firstname#
#myquery.lastname#
</CFOUTPUT>
Database Access: In Java
! Set the DataSource using a GUI tool (e.g., Jrun
Mgt Console )
! In “default server”
! Edit “jdbc data sources”
! Click edit to create a new one
! If already defined on server in odbc
! Enter its name, in “name” (ie, cfexamples)
! Enter sun.jdbc.odbc.JdbcOdbcDriver for “driver”
! Enter “jdbc:odbc:cfexamples” for url
! Enter any other needed info (userid, password)
! “Update”, then “test”
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Database Access: In Java
! In page, import needed libraries
<%@ page import="java.sql.*, javax.sql.*,
javax.naming.*" %>
! Obtain a reference to the DataSource using JNDI
<% InitialContext aContext = new
InitialContext();
DataSource myDataSource = (DataSource)
aContext.lookup(“java:comp/env/jdbc/cfexampl
es”);%>
Database Access: In Java
! Call the DataSource method
getConnection() to establish a connection
Connection con =
myDataSource.getConnection();
Database Access: In Java
! Create/Prepare the Statement
PreparedStatement aStatement =
con.prepareStatement(“select firstname,
lastname from cfexamples where empid = ?”);
aStatement.setInt(1, 2);
! Sets the first parameter (?) to the value 2
! Finds empid=2
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Database Access: In Java
! Execute the query using the Statement
object’s method executeQuery() method or
the CallableStatement object’s execute()
method.
ResultSet rs = aStatement.executeQuery();
! Accessing the data from the ResultSet
rs.getString(1);
rs.getString(2);
Displaying ResultSet: Scriptlets
! One Row
if(rs.next()) {
out.println(“Hello “ +
rs.getString(1) +
“ “ +
rs.getString(2));
}
! Many Rows
while(rs.next()) {
out.println(“Hello “ +
rs.getString(1) +
“ “ +
rs.getString(2));
}
Displaying ResultSet: JSP
! One Row
<% if(rs.next()) { %>
Hello <%= rs.getString(1); %>
<%= rs.getString(2); %>
<% } %>
! Many Rows
<% while(rs.next()) { %>
Hello <%= rs.getString(1); %>
<%= rs.getString(2); %>
<% } %>
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More topics to learn
! Java
! Language, libraries, data types
! Concepts like classes, methods, packages,
public/private/protected/”friendly”, static/final, much
more
! J2EE
! JDBC, Enterprise Java Beans, JINI, JNDI, JMS, etc.
! JSP
! JSP Custom Tags
! JSP Page Directives
! Error Handling …
More topics to learn
! SQL in scripts vs EJB
! Servlets/JSP
! Request/response objects, headers, response
codes
! Integrating servlets and JSP’s
! Battle line among supporters of each
! Best used in tandem, where each best fits
! And much more
Learning More
! Excellent documentation with Jrun
! Several books
! Core Servlets and JSP, Marty Hall
! Professional JSP, Wrox Press
! Pure JSP, James Goodwill
! Java Server Pages Application Development, Scott
Stirling, Ben Forta, et al
! And others
! Thinking in Java, Bruce Eckel
! eckelobjects.com
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Learning More
! Several CFDJ Articles
! Java For Cfers, Ben Forta
! 3 parts, starting November 2000
! ColdFusion & Java: A Cold Cup o’ Joe, Guy
Rish
! 9 parts, starting in Jan 2001
! Also see Java Developer’s Journal
JSP/Servlet Engine Providers
! Allaire Jrun
! 3 person developer edition available free!
! Can install on same server as CF Server
! IBM WebSphere
! BEA WebLogic
! Apache/TomCat
! others
Java Editing Tools
! Jrun Studio
! CF Studio also supports JSP
! Kawa
! Others, from competing JSP engine
providers
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CF 6.0 AKA NEO
! CF, as we know it
! But on top of a Java, rather than C++ platform
! Basically transparent to CF developers
! Strength of JAVA, ease of CF
! Backwards compatibility
! Scalability built on a leading container (JRUN)
! May be made available on other Java Server
vendor platforms (IBM, BEA, etc.)
! Still being debated by Allaire, I understand
Leveraging Java in CF Today
! CFSERVLET
! CFOBJECT
! Java Custom Tags
! TagServlet (from n-ary.com)
! “wolf in sheep’s clothing” trick
! How to look like you’re converting your CF
code to use JSP when you’re really not ☺
Times Up!
! Hope you enjoyed the session
! Send questions to:
! Charlie Arehart
! Carehart@systemanage.com
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