SERVLETS (2).pptxintroduction to servlet with all servlets

UNIT3-SERVLETS
 Building a Web Application in Eclipse,
 Introduction to Servlets: Lifecycle of a
Servlet,The Servlet API, Reading Servlet
parameters, Reading initialization
parameters, Handling HTTP Request &
Responses, writing and deploying
Servlets,
 Session management using Hidden
fields, Cookies and sessions and URL
rewriting, Request Dispatcher,
 Connecting to a database from servlet
using JDBC.

UNDERSTANDING CLIENT AND SERVER SIDE
SCRIPTING
 Web-Site Structure
2
 Steps
1. Request Content(Client)
2. Get response back(Server)
 Additional Steps
 1.x Execute a script in the client side
 2.x: Execute a script in the server side
 Calculate something
 Retrieve data from a database
 3. Execute script in the client side

DEFINITION
 Client Side Scripting
 computer programs on the web
 that are executed client-side, by the user's web browser
 JavaScript
 Jquery
 VBScript
 Server Side Scripting
 computer programs on the web
 that are executed server-side
 usually used to provide interactive web sites
 that interface to databases or other data stores
 PHP
 Perl
 Ruby
 JSP
 Servlets 4

WHAT IS A WEB SERVER?
• A web server is a system that delivers
content(web pages) or services to end
users over the internet.
• The basic objective of the web server is to
store, process and deliver web pages to
the users.
• This intercommunication is done using
Hypertext Transfer Protocol (HTTP).

• Program that understands the HTTP protocol
and generates appropriate responses
– Clients “connect” to the machine
– Clients send a “request”
– Server reads request, generates “response”
– Client interprets response appropriately
WHAT IS A WEB SERVER?

WEB SERVERS
Popular Web Servers
Apache
Windows IIS
IBM Websphere
Apache server is the most common web server
available in the market. Apache is an open
source software that handles almost 70 percent
of all websites available today.

SERVLETS (2).pptxintroduction to servlet with all servlets

PROVIDE HTTP PORT NUMBER :
8080

WHAT IS WEB APPLICATION?
• A web application is an application accessible
from the web. A web application is composed
of web components like Servlet, JSP, Filter etc.
and other components such as HTML. The
web components typically execute in Web
Server and respond to HTTP request.

Disadvantages of CGI
1. If number of clients increases, it takes more time for
sending response.
2. It uses platform dependent language e.g. C, C++, perl.
3. For each request CGI Server receives, It creates new
Operating System Process.
4. If the number of requests from the client increases
then more time it will take to respond to the request.
5. As programs executed by CGI Script are written in
the native languages such as C, C++, perl which are
platform dependent.

Advantages of Servlet
 Performance
 The performance of servlets is superior to CGI because
there is no process creation for each client request.
 Each request is handled by the servlet container process.
 After a servlet has completed processing a request, it stays
resident in memory, waiting for another request.
 Portability
 Like other Java technologies, servlet applications are portable.
 Rapid development cycle
 As a Java technology, servlets have access to the rich Java
library that will help speed up the development process.
 Robustness
 Servlets are managed by the Java Virtual Machine.
 Don't need to worry about memory leak or garbage collection,
which helps you write robust applications.
 Widespread acceptance
 Java is a widely accepted technology.

Life Cycle of Servlet
Initialization
init()
Service
service()
doGet()
doPost()
doDelete()
doHead()
doTrace()
doOptions()
Destruction
destroy()
Concurrent
Threads
of Execution

Life Cycle Methods
• init() :
– Servlet loads and initializes the servlet
• service():
– Servlet handles one or more client Request and
Responses to the client
• destroy():
– Servlet is deactivated or server is terminated
– Memory allocated for the servlet and its object are
garbage collected
Note: All above methods are inherited from GenericServlet class

public void service(ServletRequest
req,ServletResponse res) throws
ServletException,IOException
{
res.setContentType("text/html");
// server responds in HTML format
PrintWriter out=res.getWriter();
}

Sample Servlet Example
import java.io.*;
import javax.servlet.*;
public class ServletExample extends GenericServlet
{
public void service(ServletRequest req,ServletResponse res) throws
ServletException,IOException
{
res.setContentType("text/html"); // server responds in HTML format
PrintWriter out=res.getWriter();
out.println("<html>");
out.println("<body>");
out.println("Hello World...");
out.println("</body>");
out.println("</html>");
}
}

Directory Structure
ROOT
Save
.java program

Web.xml(Deployment Descriptor) is an XML document that
defines everything about your application that a server needs to
know

Web.xml(Deployment Descriptor file)

ServletContext and ServletConfig
Both ServletContext and ServletConfig a
re basically the configuration objects
which are used by the servlet container to
initialize the various parameter of a web
application. But they have some
difference in terms of scope and
availability.
Difference between ServletConfig vs.
ServletContext

• An object of ServletConfig is createdby the web
container for each servlet.
• This object can be used to get configuration
information from web.xml file.
• If the configuration information is modified
from the web.xml file, we don't need to change
the servlet.
• So it is easier to manage the web application if
any specific content is modified from time to
time.

ServletConfig ServletContext
ServletConfig object is one per servlet class. ServletContext object is global to the entire web application.
Object of ServletConfig will be created during the initialization
process of the servlet.
Object of ServletContext will be created at the time of web
application deployment
We have to give the request explicitly in order to create the
ServletConfig object for the first time.
ServletContext object can be available even before giving the
first request.
Scope: As long as a servlet is executing, the ServletConfig object
will be available, it will be destroyed once the servlet execution
is completed.
Scope: As long as a web application is executing, the
ServletContext object will be available, and it will be destroyed
once the application is removed from the server.
ServletConfig object is used while only one servlet requires
information shared by it.
ServletContext object is used while application requires
information shared by it.
getServletConfig() method is used to obtain Servletconfig object. getServletContext() method is used to obtain ServletContext
object.
In web.xml — tag will be appear under tag. In web.xml — tag will be appear under tag.

Reading Initialization paramters
• Sometimes we may have a requirement that a
value keeps changing time to time and so we do
not want to hard code it into a servlet.
• If it is done, we will have to change the value and
again recompile the servlet.
ServletConfig config=getServletConfig();
String name=config.getInitParameter(“uname");

Deployment Descriptor file(Web.xml)
<web-app>
<servlet>
<servlet-name>DemoServlet</servlet-name>
<servlet-class>DemoServlet</servlet-class>
<init-param>
<param-name>uname</param-name>
<param-value>scott</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>DemoServlet</servlet-name>
<url-pattern>/servlet1</url-pattern>
</servlet-mapping>
</web-app>

Reading Init Parameters
web.xml
<web-app>
<servlet>
<servlet-name>Config</servlet-name>
<servlet-class>ConfigDemo</servlet-class>
<init-param>
<param-name>username</param-name>
<param-value>vnrvjiet</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>Config</servlet-name>
<url-pattern>/welcome</url-pattern>
</servlet-mapping>
</web-app>

ConfigDemo.java
// Import required java libraries
import java.io.*;
import javax.servlet.http.*;
// Extend HttpServlet class
public class ConfigDemo extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// Set response content type
response.setContentType("text/html");
// Actual logic goes here.
PrintWriter out = response.getWriter();
//get ServletConfig object.
ServletConfig config=getInitServletConfig();
//get init parameter from ServletConfig object.
String name= config.getParameter("username");
out.println("Welcome "+name);
out.close()
}}

Reading Initialization Parameters in multiple
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class DemoServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
ServletConfig config=getServletConfig();
Enumeration<String> e=config.getInitParameterNames();
String str="";
while(e.hasMoreElements()){
str=e.nextElement();
out.print("<br>Name: "+str);
out.print(" value: "+config.getInitParameter(str));
} out.close(); }
}

Reading Servlet Parameters
<html>
<body>
<form action = "HelloForm" method = "GET">
First Name: <input type = "text" name =
"first_name"> <br />
Last Name: <input type = "text" name =
"last_name" />
<input type = "submit" value = "Submit" />
</form>
</body> </html>

How to read servlet parameters
// Get enumeration of parameter names.
Enumeration e = request.getParameterNames();
// Display parameter names and values.
while(e.hasMoreElements())
{
String pname = (String)e.nextElement();
pw.print(pname + " = ");
String pvalue = request.getParameter(pname);
pw.println(pvalue);
}

// Import required java libraries
import java.io.*;
// Extend HttpServlet class
public class HelloForm extends HttpServlet {
// Method to handle GET method request.
public void doGet(HttpServletRequest request, HttpServletResponse
response)
// Set response content type
out.println("<html>" +"<ul>n" +”<li><b>First Name</b>: "+
request.getParameter("first_name") + "n" +" <li><b>Last Name</b>: " +
request.getParameter("last_name") + "n" +
"</ul>n" +
" </html>"
); }

• The HttpServletRequest Interface
The HttpServletRequest interface
enables a servlet to obtain
information about a client request.
• The HttpServletResponse
Interface The HttpServletResponse
interface enables a servlet to
formulate an HTTP response to a
client.

• The HttpSession interface enables a
servlet to read and write the state
information that is associated with
an HTTP session.. All of these
methods throw an
IllegalStateException if the session
has already been invalidated.

• Why use Session Tracking?
• To recognize the user It is used to
recognize the particular user.
• Session Tracking Techniques
• There are four techniques used in
Session tracking:
• Cookies
• Hidden Form Field
• URL Rewriting
• HttpSession

The names and values of cookies
are stored on the user’s machine.
Some of the information that is
saved for each cookie includes the
following:
• The name of the cookie
• The value of the cookie
• The expiration date of the cookie
• The domain and path of the cookie

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CREATING COOKIE PROGRAM
Index.html
<form method="post" action="validate">
Name:<input type="text" name="user" /><br/>
Password:<input type="text" name="pass" ><br/>
<input type="submit" value="submit"> </form>
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MyServlet.java
import java.io.*;
public class MyServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse
response)
response.setContentType("text/html;charset=UTF-8");
String name = request.getParameter("user");
String pass = request.getParameter("pass");
if(pass.equals("1234"))
{
Cookie ck = new Cookie("username",name);
response.addCookie(ck);
response.sendRedirect("First");
}
}
}
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First.java
import java.io.*;
public class First extends HttpServlet {
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
response.setContentType("text/html ");
Cookie[] cks = request.getCookies();
out.println("Welcome "+cks[0].getValue());
}
}
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<web-app...>
<servlet>
<servlet-name>validate</servlet-name>
<servlet-class>MyServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>validate</servlet-name>
<url-pattern>/validate</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>First</servlet-name>
<servlet-class>First</servlet-class>
</servlet>
<servlet-mapping>
<url-pattern>/First</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
</web-app>
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HTTP SESSION
 A session contains information specific to a particular user across
the whole application. When a user enters into a website (or an
online application) for the first time HttpSession is obtained via
request.getSession(), the user is given a unique ID to identify his
session.
 The HttpSession stays alive until it has not been used for more than
the timeout value specified in tag in deployment descriptor
file( web.xml). The default timeout value is 30 minutes, this is used
if you don’t specify the value in tag. This means that when the user
doesn’t visit web application time specified, the session is
destroyed by servlet container. The subsequent request will not be
served from this session anymore, the servlet container will create
a new session.
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 Commonly used Methods of Servlet HttpSession
 setAttribute(String name, Object value): Binds an object to this session,
using the name specified.
setMaxInactiveInterval(int interval): Specifies the time, in seconds,
between client requests before the servlet container will invalidate this
session.
getAttribute(String name): Returns the object bound with the specified
name in this session, or null if no object is bound under the name.
getAttributeNames(): Returns an Enumeration of String objects containing
the names of all the objects bound to this session.
getId(): Returns a string containing the unique identifier assigned to this
session.
invalidate(): Invalidates this session then unbinds any objects bound to it.
removeAttribute(String name): Removes the object bound with the
specified name from this session.
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sessionemo.html
<html>
<head>
<title>session Demo</title>
</head>
<body>
<form action="servlet1" method="post">
Enter Your Name:<input type="text"
name="userName"/><br/><br/>
<input type="submit" value="SUBMIT"/>
</form>
</body>
</html>
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SetSessionServlet.java
import java.io.*;
public class SetSessionServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse
response){
try{
String name=request.getParameter("userName");
// Create a session object.
HttpSession session = request.getSession(true);
session.setAttribute("uname",name);
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//creating submit button
out.print("<br><form action='servlet2'
method='post'>");
out.print("<input type='submit' value='View the
session'>");
out.print("</form>");
out.close();
}
catch(Exception e){
System.out.println(e);
} }}
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GetSessionServlet.java
import java.io.*;
public class GetSessionServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse
response){
try{
HttpSession session=request.getSession(false);
String name=(String)session.getAttribute("uname");
out.print("Hello!.. Welcome "+name);
out.close(); }catch(Exception e){ System.out.println(e); }
}}
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web.xml
<web-app>
<servlet>
<servlet-name>set</servlet-name>
<servlet-class>SetSessionServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>set</servlet-name>
</servlet-mapping>
<servlet>
<servlet-name>get</servlet-name>
<servlet-class>GetSessionServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>get</servlet-name>
</servlet-mapping>
</web-app>

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HIDDEN FORM FIELD
<form method="post" action="validate">
Name:<input type="text" name="user" /><br/>
Password:<input type="text" name="pass" ><br/>
<input type="submit" value="submit"> </form>
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FIRST.JAVA
import java.io.*;
public class First extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response)
//getting value submitted in form from HTML file
String user = request.getParameter("user");
//creating a new hidden form field
out.println("<form action='Second'>");
out.println("<input type='hidden' name='user' value='"+user+"'>");
out.println("<input type='submit' value='submit' >");
out.println("</form>");
}
}
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SECOND.JAVA
import java.io.*;
public class Second extends HttpServlet {
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
//getting parameter from the hidden field
String user = request.getParameter("user");
out.println("Welcome "+user);
}
}
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WEB.XML
<web-app...>
<servlet>
<servlet-class>First</servlet-class>
</servlet>
<servlet-mapping>
<url-pattern>/First</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>Second</servlet-name>
<servlet-class>Second</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Second</servlet-name>
<url-pattern>/Second</url-pattern>
</servlet-mapping>
<welcome-file-list>
</web-app>
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URL REWRITING
In URL rewriting, we append a token or identifier to the
URL of the next Servlet or the next resource. We can
send parameter name/value pairs using the following
format:
url?name1=value1&name2=value2&??
A name and a value is separated using an equal = sign,
a parameter name/value pair is separated from another
parameter using the ampersand(&). When the user
clicks the hyperlink, the parameter name/value pairs
will be passed to the server. From a Servlet, we can use
getParameter() method to obtain a parameter value.
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SESSION TRACKING
1.On client's first request, the Web Container
generates a unique session ID and gives it back to
the client with response. This is a temporary
session created by web container.
2.The client sends back the session ID with each
request. Making it easier for the web container to
identify where the request is coming from.
3.The Web Container uses this ID, finds the
matching session with the ID and associates the
session with the request.
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INDEX.HTML
<form method="post" action="Validate">
User: <input type="text" name="user" /><br/>
Password: <input type="text" name="pass" ><br/>
<input type="submit" value="submit">
</form>
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VALIDATE.JAVA
import java.io.*;
public class Validate extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse
response)
String name = request.getParameter("user");
String pass = request.getParameter("pass");
if(pass.equals("1234"))
{
//creating a session
HttpSession session = request.getSession();
session.setAttribute("user", name);
response.sendRedirect("Welcome");
}
}
}
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WELCOME.JAVA
import java.io.*;
public class Welcome extends HttpServlet {
protected void doGet(HttpServletRequest
request, HttpServletResponse response)
response.setContentType("text/html”);
HttpSession session = request.getSession();
String user =
(String)session.getAttribute("user");
out.println("Hello "+user);
}}
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WEB.XML
<web-app..>
<servlet>
<servlet-name>Validate</servlet-name>
<servlet-class>Validate</servlet-class>
</servlet>
<servlet>
<servlet-name>Welcome</servlet-name>
<servlet-class>Welcome</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Validate</servlet-name>
<url-pattern>/Validate</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>Welcome</servlet-name>
<url-pattern>/Welcome</url-pattern>
</servlet-mapping>
<welcome-file-list>
</web-app>
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JAVA DATABASE
CONNECTIVITY(JDBC)
• Java Database Connectivity(JDBC) is
an Application Programming Interface(API)
used to connect Java application with Database.
• JDBC is used to interact with various type of
Database such as Oracle, MS Access, My SQL
and SQL Server.
• It allows java program to execute SQL
statement and retrieve result from database.

JDBC IN JAVA
• Jdbc is a part of JDK software so no need to
install separate software for Jdbc API
• Jdbc API consists of two packages
java.sql package
javax.sql package

• JDBC Architecture consists of two layers −
JDBC API: This provides the application-to-JDBC Manager
connection.
JDBC Driver API: This supports the JDBC Manager-to-
Driver Connection.
• The JDBC API uses a driver manager and database-specific
drivers to provide transparent connectivity to heterogeneous
databases.
• The JDBC driver manager ensures that the correct driver is
used to access each data source.

JDBC DRIVER
• JDBC Driver is a software component that
enables java application to interact with the
database.
• Types of drivers
JDBC-ODBC bridge driver
Native-API driver (partially java driver)
Network Protocol driver (fully java driver)
Thin driver (fully java driver)

TYPE 1 : JDBC-ODBC BRIDGE
DRIVER
• The JDBC-ODBC is also known as Type 1 driver.
• The JDBC-ODBC bridge driver converts the JDBC method call into the
ODBC function call.
• This driver is platform dependent.
• Sun provides the JDBC-ODBC Bridge driver by following URL -
“sun.jdbc.odbc.JdbcOdbcDriver”
• Advantage
 Easy to use
 Allow easy connectivity to all database supported by the ODBC
Driver.
• Disadvantage
• Slow execution time
• Dependent on ODBC Driver.

TYPE 2 : NATIVE API DRIVER
(PARTIAL JAVA DRIVER)
• The Native API driver is also known as Type 2 driver.
• It uses the client-side libraries of the database.
• must be installed on each client system.
• This driver converts the JDBC method call into native
call of database.

Advantage
faster as compared to Type-1 Driver
Disadvantage
Requires native library
Type 2 driver is platform
dependent.
It does not support applet
programming.

TYPE 3 : NETWORK PROTOCOL
DRIVER
• The Network protocol driver uses the
three- tier model.
• The middle tier is responsible to
converts JDBC calls directly or
indirectly into vender specific
database protocol.
• This type of driver is very flexible
that is a single driver can actually
provide access to multiple
databases.

Advantage
Does not require any native library to be installed.
Database Independency.
Disadvantage
Slow due to increase number of network call.

TYPE 4 : THIN DRIVER (PURE JAVA
DRIVER)
• It is a pure Java driver which connects all Java
drivers directly to the vendor specific
database protocol.
• This driver provides the highest performance
driver for the database.
• Thin driver is completely written in Java
because of that it is known as 100% pure Java
driver.

JDBC - SQL
SYNTAX
• Create Database
CREATE DATABASE DATABASE_NAME;
Create a Database named EMP ?
CREATE DATABASE EMP;
• Drop Database
DROP DATABASE DATABASE_NAME;
• Create Table
CREATE TABLE table_name ( column_name
column_data_type, column_name
column_data_type, column_name column_data_type ... );

CREATE TABLE Employees ( id INT NOT NULL,
INT NOT NULL,
age
first
last
VARCHAR(255),
VARCHAR(255),
PRIMARY KEY ( id )
);
CREATE AN EMPLOYEE
TABLE?
INSERT Data:
INSERT INTO
...);
table_name VALUES (column1, column2,

INSERT A NEW ROW IN THE EMPLOYEES
DATABASE CREATED EARLIER ?
INSERT INTO Employees VALUES (100, 18, ‘cse', ‘vnr');
SELECT Data
SELECT column_name, column_name, ... FROM
table_name WHERE conditions;
The WHERE clause can use the comparison operators such as =, !
=,
<, >, <=,and >=, as well as the BETWEEN and LIKE operators.

• To select the age, first and last columns
from the Employees table, where id column is
100 ?
•
SELECT
FROM
WHERE
first, last, age
Employees
id = 100;
• UPDATE Data
UPDATE table_name
SET column_name =
value, WHERE
conditions;
column_name = value, ...

• To UPDATE statement changes the age column
of the employee whose id is 100 ?
• UPDATE Employees SET age=20 WHERE id=100;
• DELETE Data
• DELETE FROM table_name WHERE
conditions;
• DELETE statement deletes the record of the
employee whose id is 100 ?
• DELETE FROM Employees WHERE
id=100;

STEPS TO CONNECT A JAVA
APPLICATION
TO DATABASE
1. Register the Driver
2. Create a Connection
3. Create SQL Statement
4. Execute SQL Statement
5. Closing the connection

• Register the Driver
Class.forName() is used to load the driver class
explicitly.
• Example to register with JDBC-ODBC Driver
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
• Create a Connection
getConnection() method of DriverManager class is
used to create a connection.

DRIVERMANAGER CLASS
• Syntax
getConnection(String url)
getConnection(String url, String username, String password)
getConnection(String url, Properties info)
Example establish connection with Oracle Driver
Connection con =
DriverManager.getConnection("jdbc:odbc:DSN","username",
"password");

CREATE SQL
STATEMENT
• The Connection interface provides
the createStatement() method to create SQL
statement.
• Syntax:
public Statement createStatement( ) throws
SQLException
• Example:
Statement stmt = con.createStatement();

EXECUTE SQL QUERIES
• The Statement interface provides
the executeQuery( ) method to execute SQL
statements.
• Syntax:
public ResultSet executeQuery(String
sql) throws SQLException

• Example:
• ResultSet rs = stmt.executeQuery("select * from students");
while (rs.next())
{
System.out.println (rs.getInt(1)+" "+rs.getString(2)+"
"+rs.getFloat(3));
}
• Closing the Connection
• The Connection interface provides close( ) method, used to
close the connection.
• Example:
con.close( );

STATEMENT
INTERFACE IN JDBC
• The Statement interface provides methods to execute queries
with the database.

RESULTSET
INTERFACE IN JDBC
• The object of ResultSet maintains a cursor pointing to a
particular row of data. Initially, cursor points to before the first
row.

HOW TO CREATE JDBC
CONNECTION?

WHAT ARE THE TYPES OF
JDBC STATEMENTS
AVAILABLE?
• There are 3 types of Statements, as given below:
Statement:
It can be used for general-purpose access to the database. It is
useful when you are using static SQL statements at runtime.
PreparedStatement:
It can be used when you plan to use the same SQL statement many
times. The PreparedStatement interface accepts input parameters
at runtime.
CallableStatement:
CallableStatement can be used when you want to access database
stored procedures.

CONNECTION
CON;
PreparedStatement pstmt =
con.prepareStatement("sql command");
Example:
PreparedStatement pstmt =
con.prepareStatement("Insert into emp
value(?,
?)");
The each ? represent the column index number in the table. If
table EMP has id, name columns, then 1st ? refer to id, 2nd ?
refer to name.
Afterthat we need to set the value to each ? by using the
setter method from PreparedStatement interface as follows :
Syntax : setXXX(ColumnIndex, value)

METHODS OF PREPAREDSTATEMENT
INTERFACE

PREPAREDSTATEMENT
INTERFACE
• It represents precompiled SQL statements and
stores it in a PreparedStatement object.
• It increases the performance of the application
because the query is compiled only once.
• The PreparedStatement is easy to reuse with new
parameters.

CREATING
PREPAREDSTATEMENT
OBJECT
• Syntax
Connection con;
PreparedStatement
String sql
=
pstmt = con.prepareStatement("sql command");
"Select * from Student where rollNo= ?";
• PreparedStatement ps
=
con.prepareStatement(sql);

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