Cookies

Cookies

10/31/2012 R.V.S.Lalitha.,M.Tech(Ph.D) 1

Cookie
• Class Name: javax.servlet.http.Cookie
• Super class: java.lang.Object
• Immediate subclasses: None
• Interfaces implemented: java.lang.Cloneable


Purpose
• The Cookie provides an easy way for servlets to
read, create and manipulate HTTP-style cookies,
which allow servlets to store small amounts of data
on the client.
• Cookies are generally used for session tracking
or storing small amounts of user-specific
configuration information.


Class summary
public class Cookie implements java.lang.Cloneable {
//constructor
public Cookie(String name,String value)l
//instance methods
public Object Clone();
public String getComment();
public String getDomain();
public String getMaxAge();
public String getName();
public String getPath();
public String getSecure();
public String getValue();
public String getVersion();

Class summary
public void setComment(String purpose);
public void setDomain(String pattern);
public void setMaxAge(int Expiry);
public void setPath(String uri);
public void setSecure(boolean flag);
public void setDomain(String pattern);
public void setValue(String newValue);
public void setVersion(int v);
}


Class summary
• Cookie()
Constructs a new cookie with a initial name and value
• clone()
To return a copy of object(duplicate cookie)
• getComment()
Returns comments associated with cookie
• getDomain()
Returns domain limitation associated with cookie
• getMaxAge()
Returns max age allowed for this cookie
• getPath
Returns path limitation for this servlet
• getSecure()
Returns true if the cookie requires a secure connection, false
otherwise

• getName()
Returns name of the cookie
• getValue()
Returns value of the cookie in String format
• getVersion()
Returns version of the cookie
• setComment()
Sets the comment field of the cookie
• setDomain()
Specifies domain restriction pattern
• setMaxAge()
Specifies the maximum age of the cookie
• setPath()
Specifies path for cookie
• setSecure()
The secure flag indicates whether the cookie should be sent only over a secure
channel, such as SSL
• setValue()
Assigns new value to a cookie
• setVersion()
Servlets can send and receive cookies formatted to match either Netscape persistent
cookies or the newer

Sample servlet to implement cookie
• cookiesform.html
<html>
<head><title>Cookies</title></head>
<body>
<form action="http://localhost:8080/lalitha/cookie">
Enter name
<input type="text" name="t1"/><br>
Enter qualification
<input type="text" name="t2"/><br>
<input type="submit" name="submit" value="Submit"/>
</form>
</body>
</html>


• cookie.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class cookie extends HttpServlet {
public void doGet(HttpServletRequest req,
HttpServletResponse res)
throws IOException, ServletException
{
res.setContentType("text/html");
PrintWriter out = res.getWriter();
String name=req.getParameter("t1");
String qual=req.getParameter("t2");
Cookie c=new Cookie(name,qual);
res.addCookie(c);
out.println("cookies are added");
}
}


• cookieview.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class cookieview extends HttpServlet {
public void doGet(HttpServletRequest req,
HttpServletResponse res)
throws IOException, ServletException
{
res.setContentType("text/html");
PrintWriter out = res.getWriter();
Cookie[] c=req.getCookies();
for(int i=0;i<c.length;i++)
{
out.println(c[i].getName());
}
}
}


• web.xml
<web
<servlet>
<servlet-name>cookie</servlet-name>
<servlet-class>cookie</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>cookie</servlet-name>
<url-pattern>/cookie</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>cookieview</servlet-name>
<servlet-class>cookieview</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>cookieview</servlet-name>
<url-pattern>/cookieview</url-pattern>
</servlet-mapping>
</web-app>

Compiling servlets..
C:Program FilesApache Software FoundationTomcat
5.5webappslalithaWEB-INFclasses>javac -classpath "C:Program
FilesApache Software oundationTomcat 5.5commonlibservlet-
api.jar" cookie.java

C:Program FilesApache Software FoundationTomcat
5.5webappslalithaWEB-INFclasses>javac -classpath "C:Program
FilesApache Software FoundationTomcat 5.5commonlibservlet-
api.jar" cookieview.java


Running Html file

• C:Program FilesApache Software
FoundationTomcat
5.5webappslalithacookiesform.html


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