GAC Java Presentation_Server Side Include_Cookies_Filters 2022.ppt
- 1. GOVERNMENT ARTS COLLEGE Melur, Madurai By Mr. V. Veeranan Roll No: P22PCS123 I M.Sc. Computer Science Topic: Server Side Include (Cookies and Filters) PG. Department of Computer Science ADVANCED JAVA PROGRAMMING
- 2. Server Side Includes (SSI) Embed instructions to the Server Inside an HTML document HTML tag Language A special file -> .shtml SHTML -> the web server Servlets To add small of dynamic content Otherwise static HTML pages
- 3. Server-side Includes(SSI) Server-Side Includes (SSI) give you the ability to embed instructions to the server inside an HTML document. The instructions are given using extensions to the HTML tag language. A special file extension, . shtml, signals the server that the document contains SSI directives. SHTML is a file extension that lets the web server know the file should be processed as using Server Side Includes(SSI) Servlets are not confined to handling entire requests. Some web servers allow servlets to add small amounts of dynamic content to otherwise static HTML pages.
- 4. Server Side Include Tag A page that uses the advertisement servlet is written just like a normal HTML page, except that it contains one or more <SERVILET> tags and is saved with the .shtml extension. • The <SERVIET> tag is similar to the <APPLET> tag, which loads an applet within a page. When a client requests a .shtml page, the server finds all of the <SERVLET> tags in the text and replaces them with the output from the appropriate servlets. • When you use a <SERVLET> tag, you must include a CODE parameter that identifies the servlet to be loaded. This can be a class name or a servlet allas set up within the server. On some servers, you can specify an optional CODEBASE parameter that loads the servlet code from a remote location.
- 5. Server Side Include • Any additional parameters are treated as servlet initialization parameters. Each <SERVLET> tag must be matched by a closing</SERVLET> tag. • Between the opening and closing tags, you can include as many <PARAM> tags as necessary, where you specify NAME and VALUE attributes for each one. • The servlet can them access these parameters with getParameter().
- 6. Example (Time.shtml) <HTML> <HEAD> <TITLE> Times1</TITLE></HEAD> <BODY> The current time here is: <SERVLET CODE=CurrentTime> </SERVLET> <p> The current time in London is: <SERVLET CODE
- 7. Cookies • Cookies is a small text file containing client information sent by a web server to a browser that can later be read back from the browser. • When a browser receives a cookie, it saves the cookie and there after sends the cookie back to the server each time it accesses a page on the server, subject to certain rules. • Since cookie’s value can uniquely identify a client, cookies are often used for session tracking. • The browser is expected to support 20 cookies for each Web server, 300 cookies total any may limit cookie size to 4kb each.
- 8. Cookies Working with Cookies Cookies Methods
- 9. Working with Cookies Create Cookie Class Constructor public Cookie(String name, String Value()) Create Cookie, Send -> Browser HttpServletResponce.addCookie(Cookie Cokie) Servlet -> Request HttpServletRequest.getCookies()
- 10. Cookie Methods Specifies a Comment public void setComment(java.lang.String purpose) Comment using describing public java.lang.String getComment() Specifies the Domain name public void setDomain(java.lang.String pattern) The Maximum age -> Cookie public void setMaxAge(int expiry) Positive Vallue -> Negative value -> Zero Value Return the Maximum age -> Cookie public int setMaxAge() Set of URIs -> Client public void setPath(java.lang.String.url)
- 11. Cookie Methods Returns the Paths public java.lang.String.getPath() Indicates to the Browser public vaid setSecure(boolean flag) Returns true if -> Browser -> Sending public Boollean getSecure()
- 12. Filters Filter is a component which dynamically intercepts requests and responses to transform or use the information contained in the requests or response, Filters typically do not themselves create responses but provide universal functions that can be “attached” to any type of servlet or JSP page. A filter is a program that runs on the server before the servlet with which it is associated.
- 13. Benefits of Filters Filters encapsulates common behaviour in a modular and reusable manner. It separates high-level access decisions from presentation code. It applies wholesale changes to many different resources.
- 14. Types/Components of Filters Filters can perform many different types of functions. Based on their functionalities following are the filters Authentication: Blocking requests based on user identity. Logging and auditing: Tracking users of a web application. Image conversion: Scaling maps and so on. Localization: Targeting the request and response to particular locale. XSL/T Transformations of XML Content: Targeting web application responses to more than one type of client.
- 15. Programming a Filter Create a class that implement the filter interface Put the filtering behaviour in the doFilter method Call the doFilter Method of the FilterChain object Register the filter with the appropriate servlets and JSP pages Disable the invoker servlet.
- 16. Filter Element in web.xml Icon Filter-name Display-name Description Filter-class Init-param Filter-Mapping Element Filter-name url-pattern Servlet-name
- 17. Process of Registering Filter with Servlet One filter can be associated with more than one servlet. More than one filter can be mapped to a servlet. A filter can be mapped to all the servlet using an “*”. The filter, filter-mapping, serdfsdvlet and servlet-mapping element must appear in the web application deployment descriptor in that order.
- 18. Filter Life Cycle Methods Controlling life cycle of a filter are as follows init() doFilter() destroy() Three methods of Filter interface makes up the life cycle of a filter. public void init(FilterConfig config) throws ServletException public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException public void destroy()
- 19. Thank You…
Editor's Notes
- #2: Connected component