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Java : Servlet Tutorials
- History of Web
application
Earlier in client- server computing, each application had its own
client program and it worked as a user interface and need to be
installed on each user's personal computer.
- Introduction
to Web Server
A Web Server is a computer on the World Wide Web that
stores Html documents that can be retrieved via a Web browser. It is a
computer that delivers web pages.
- What
is a Container
Container are nothing but a Java application which controls servlets.
Tomcat is one of the example of a container. It is the container which
calls the servlet's methods like doPost() and doGet().
- Overview of Servlets
What is servlet?
Methods of Servlet
Life Cycle of Servlet
Features of Servlet 2.4
Features of Servlet 2.5
Advantages of Java Servlets
Advantages of Servlets over
CGI
- Quick get to Servlet
Servlets overview
Introduction to Server Side programming
Introduction to Java Servlets
Installing Configuring and Running Servlets
- How to run a
Servlet?
Install the tomcat server in a directory in which you want to install
and set the classpath.for the variable JAVA_HOME in the environment
variable.
- Writing Hello World
We should start understanding the servlets from the beginning. Lets
start by making one program which will just print the "Hello
World" on the browser. Each time the user visits this page it will
display "Hello World" to the user.
- Displaying
Date in Servlet
In this example we are going to show how we can display a current date
and time on our browser. It is very easy to display it on our browser by
using the Date class of the java.util package.
- Simple Counter In Servlet
In this example we are going to know how we can make a
program on counter which will keep track how many times the servlet has been
accessed.
- A
Holistic counter in Servlet
In this program we are going to make a such a servlet which will count
the number it has been accessed and the number of threads created by the
server.
- Counter in
Init() Method
In this program we are going to make a such a servlet which will count
and displays the number of times it has been accessed and by reading the
init parameter to know from where the counting will begin.
- Snooping
the server
To display the name of the server you are using use the method getServerName()
of the ServletRequest interface. To display the server
port number use the method getServerPort().
- Snooping Headers
In this program we are going to going to make a servlet
which will retrieve all the Http request header.
- Dice Roller
We are going to make one program on the dice roller in
which the number in the dice will be selected randomly.
- Getting Init Parameter Names
Whenever the container makes a servlet it always reads it deployment
descriptor file i.e. web.xml. Container creates name/value pairs for the
ServletConfig object. Once the parameters are in ServletConfig they will
never be read again by the Container.
- Passing
Parameter Using Html Form
This is a very simple example in which we are going to display the name
on the browser which we have entered from the Html page.
- Multiple
values for a single parameter
In our program it may be that we may have multiples values for a single
parameter like in checkboxes.
- Time Updater in Servlet
In this program we are going to make one program on
servlet which will keep on updating the time in every second and the result will
be displayed to you.
- Send Redirect in Servlet
In this example we are going to make one html in which
we will submit the user name and his password. The controller will check if the
password entered by the user is correct or not.
- Session Tracking
As we know that the Http is a stateless
protocol, means that it can't persist the information. It always treats each
request as a new request. In Http client makes a connection to the server, sends
the request., gets the response, and closes the connection.
- To Determine whether the Session is New or Old
In this program we are going to make one servlet on
session in which we will check whether the session is new or old.
- Pre- Existing Session
In this example we are going to find out whether the
session is pre- existing or not.
- Get Session Id
In this example we are going to make a program in which we will find the
session id which was generated by the container.
Connection with the Database
- Inserting
Data In Database table using Statement
In this program we are going to insert the data in the database from our
java program in the table stored in the database.
- Retrieving Data from the table using Statement
In this program we are going to fetch the data from the
database in the table from our java program.
- Inserting data from the HTML page to the database
In this program we are going to make program in which
we are going to insert the values in the database table from the html form.
- Retrieving Data from the table using PreparedStatement
In this program we are going to fetch the data from the
database in the table from our java program using PreparedStatement.
- Getting Columns Names using Servlets
Consider a situation where there is a need to know
about the name of the columns without touching our database. As we are the
programmers so why we need to worry about the database.
- Getting Number of Columns
Consider a situation where there is a need to know
about the number of columns in the table without touching our database. As we
are the programmers so why we should worry about the database.
- Getting Number of Rows
Consider a situation where we want to know about the
number of rows in the particular database table without touching our database.
We want to find out the number of rows without going touching our
back- end.
- Deleting Rows From Table
Consider a situation where we have entered some wrong
data and in later situation it starts giving problem to the organization.
- Deleting
All Rows From the database Table
Consider a situation where we have entered some wrong
data and in later situation it starts giving problem to an organization or
may become useless after sometime . Rather than go
through with that data its better to delete that data.
- How to add a column in a table
Consider a situation where the requirement
of the client gets changed and you have asked to modify the structure of
the table. In reality it is the work of the database administrator but
as a Java programmer you should know how you can modify the structure of
the table.
- How to delete a table in mysql
Consider a situation where we need to
delete a table from a database.
- changing column name
consider a scenario where we have a table
and it consists some data and a situation arises where there is a need
to change the name of the column.
- insert into statement in sql
using servlets
In this tutorial we are going to learn how
we can insert a value from a html form in the table stored in the
database.
- join tables
mysql using servlets
In this program we are going to join the
two table by using the servlets and the result will be displayed in the
browser.
- Natural
Left Join using servlets
In this program we are going to join the two table by
using the servlets and the result will be displayed in the browser. This join
will be natural left join.
- Natural
Right Join using servlets
In this program we are going to join the two table by
using the servlets and the result will be displayed in the browser. This join
will be natural right join.
- Difference
between Servlet 2.4 and Servlet 2.5
In this tutorial you will know the difference between Servlet 2.4
and Servlet 2.5
- Get
And Post Method of Http
The Get is one the simplest Http method. Its main job is to ask the
server for the resource. The Post method is more powerful request. By
using Post we can request as well as send some data to the server.
- Servlets Links
Servlets are the Java platform technology of choice for extending and
enhancing Web servers. Servlets provide a component-based,
platform-independent method for building Web-based applications, without
the performance limitations of CGI programs. And unlike proprietary
server extension mechanisms (such as the Netscape Server API or Apache
modules), servlets are server- and platform-independent.
- Select Color
In this program we are going to selected the various
color and on the basis of the selection the output will be displayed to the
user.
- sendRedirect
In send Redirect whenever the client makes any request
it goes to the container, there the container decides whether the concerned
servlet can handle the request or not.
- Send Redirect in Servlet
When we want that someone else should handle the
response of our servlet, then there we should use sendRedirect() method.
- Random
Redirector
In this program we are going to make such a servlet which will be
responsible to select a site randomly from the list of sites you have
entered. Note that the selection of the site will be randomly.
- Servlet
Context
ServletContext is a interface which helps
us to communicate with the servlet container. There is only one ServletContext
for the entire web application and the components of the web application can
share it.
- Servlet
Context Listener
ServContextListener is a interface which
contains two methods: public void
contextInitialized(ServletContextEvent event) and
public void
contextDestroyed(ServletContextEvent event).
- ServletContextListener
example
ServletContextListener is notified when the
context is initialized. It will be notified when the context is
destroyed. It closes the database connection.
- ServletContextAttributeListener
The listener ServletContextAttributeListener
is an interface and extends the java.util.EventListener class. This
listener come into existence when this interface receives notifications of
changes to the attribute list on the servlet context of a web application.
- HttpSessionListener
HttpSessionListener is an interface
which extends java.util.EventListener class. The main purpose of
this listener is to notify whenever there is a change in the list of
active sessions in a web application..
- HttpSessionListener
example
Before going into the details of the SessionListener
we should firstly know about the sessions. Whenever a client makes a
request for any resources to the server, the server receives the request
and processes the request and sends back the response.
- HttpSessionAttributeListener
The listener HttpSessionAttributeListener
is an interface and extends the java.util.EventListener class. This
listener will be called by the container whenever there there will be change to
the attribute list on the servlet session of a web application.
- HttpSessionAttributeListener
Example
This listener is used when we want to know when a attribute has been added in a
session, when a attribute has been removed and when it is replaced by another
attribute.
- httpsessionbindinglistener
HttpSessionBindingListener is a interface
which extends java.util.EventListener interface. The purpose of
the this interface is to notify an object when it is bound to or unbound from a
session.
- httpsessionbindinglistener
example
This interface has two methods: valueBound(HttpSessionBindingEvent
event) and valueUnBound(HttpSessionBindingEvent event).
- ServletRequestAttributeListener
This listener is used when we want to know when a
attribute has been added in a request, when a attribute has been removed and
when it is replaced by another attribute.
- Inserting Image in a database Table
Consider a case where we want that along with the name
of the person and its information, his image should also come with all these
things.
- say hello in spanish
In this program we are going to display
"hello" in spanish along with the date.
- Accessing Date In Servlet
In this example, we are
going to show how we can display a creation date of the session and last accessed date or time and
id on our browser. It is very easy to display it on our browser by using the Date
class of the java.util package.
- Post Message In servlet
In this example, we are going to implement posting
massage to servlet. In the following program, you will learn how to post massage.
- Show Parameter In Servlet
In this section, you will
learn how to send and put all parameter names into the table. The
following program uses two methods, which is described below.
Quick Introduction to Java Servlet
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Current Comments
2 comments so far (post your own) View All Comments Latest 10 Comments:although the matter is simple and sophisticated and eay to read but there is lack of explanations of all the matters in the website.it could have been more fine if the topic criteria is more widely displayed and explained.
Posted by yogesh on Tuesday, 02.19.08 @ 11:25am | #48971
I am really looking for more things from you
Posted by bala on Saturday, 04.21.07 @ 17:58pm | #14681