To delete cookies is very simple. If you want to delete a cookie, then you simply need to follow these three steps −Read an already existing cookie and store it in Cookie object.Set cookie age as zero using the setMaxAge() method to delete an existing cookie.Add this cookie back into the response header.Following example will show you how to delete an existing cookie named "first_name" and when you run main.jsp JSP next time, it will return null value for first_name.Example Live Demo           Reading Cookies                       ... Read More

To read cookies, you need to create an array of javax.servlet.http.Cookie objects by calling the getCookies( ) method of HttpServletRequest. Then cycle through the array, and use getName() and getValue() methods to access each cookie and associated value.Let us now read cookies that were set in the previous example −Example Live Demo           Reading Cookies                        Reading Cookies                 Let us now put the above code in main.jsp file and try to access it. If you set ... Read More

Setting cookies with JSP involves three steps −Step 1: Creating a Cookie objectYou call the Cookie constructor with a cookie name and a cookie value, both of which are strings.Cookie cookie = new Cookie("key", "value");Keep in mind, neither the name nor the value should contain white space or any of the following characters −[ ] ( ) = , " / ? @ : ;Step 2: Setting the maximum ageYou use setMaxAge to specify how long (in seconds) the cookie should be valid. The following code will set up a cookie for 24 hours.cookie.setMaxAge(60*60*24);Step 3: Sending the Cookie into the ... Read More

Cookies are usually set in an HTTP header (although JavaScript can also set a cookie directly on a browser). A JSP that sets a cookie might send headers that look something like this −HTTP/1.1 200 OK Date: Fri, 04 Feb 2000 21:03:38 GMT Server: Apache/1.3.9 (UNIX) PHP/4.0b3 Set-Cookie: name = xyz; expires = Friday, 04-Feb-07 22:03:38 GMT; path = /; domain = tutorialspoint.com Connection: close Content-Type: text/htmlAs you can see, the Set-Cookie header contains a name value pair, a GMT date, a path and a domain. The name and value will be URL encoded. The expires field is an instruction ... Read More

Cookies are text files stored on the client computer and they are kept for various information tracking purposes. JSP transparently supports HTTP cookies using underlying servlet technology.There are three steps involved in identifying and returning users -Server script sends a set of cookies to the browser. For example, name, age, or identification number, etc.Browser stores this information on the local machine for future use.When the next time the browser sends any request to the web server then it sends those cookies information to the server and server uses that information to identify the user or may be for some other ... Read More

Stored procedures are sub routines, segment of SQL statements which are stored in SQL catalog. All the applications that can access Relational databases (Java, Python, PHP etc.), can access stored procedures.Stored procedures contain IN and OUT parameters or both. They may return result sets in case you use SELECT statements. Stored procedures can return multiple result sets.Creating a Stored procedureSuppose, we have created a table named Employee in MySQL database as shown below:String createTable = "CREATE TABLE Employee("    + "Name VARCHAR(255), "    + "Salary INT NOT NULL, "    + "Location VARCHAR(255))";Following is an example of a MySQL ... Read More

Your web application may define several different filters with a specific purpose. Consider, you define two filters AuthenFilter and LogFilter. Rest of the process will remain as explained above except you need to create a different mapping as mentioned below −    LogFilter    LogFilter           test-param       Initialization Paramter        AuthenFilter    AuthenFilter           test-param       Initialization Paramter        LogFilter    /* AuthenFilter /* Filters Application OrderThe order of filter-mapping elements ... Read More

Following example shows how to print the client's IP address and the current date time, each time it would access any JSP file. This example will give you a basic understanding of the JSP Filter, but you can write more sophisticated filter applications using the same concept −// Import required java libraries import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.util.*; // Implements Filter class public class LogFilter implements Filter {    public void init(FilterConfig config) throws ServletException {       // Get init parameter       String testParam = config.getInitParameter("test-param");       //Print the init parameter ... Read More

Servlet and JSP Filters are Java classes that can be used in Servlet and JSP Programming for the following purposes To intercept requests from a client before they access a resource at the back end.To manipulate responses from the server before they are sent back to the client.There are various types of filters suggested by the specifications −Authentication FiltersData compression FiltersEncryption FiltersFilters that trigger resource access eventsImage Conversion FiltersLogging and Auditing FiltersMIME-TYPE Chain FiltersTokenizing FiltersXSL/T Filters That Transform XML ContentFilters are deployed in the deployment descriptor file web.xml and then map to either servlet or JSP names or URL patterns in ... Read More

Following is a generic example which uses getParameterNames() method of HttpServletRequest to read all the available form parameters. This method returns an Enumeration that contains the parameter names in an unspecified order.Once we have an Enumeration, we can loop down the Enumeration in the standard manner, using the hasMoreElements() method to determine when to stop and using the nextElement() method to get each parameter name.           HTTP Header Request Example                        HTTP Header Request Example                 ... Read More