PES INSTITUTE OF TECHNOLOGY, SOUTH CAMPUS DEPARTMENT OF MCA INTERNAL TEST (SCHEME AND SOLUTION) II

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1 PES INSTITUTE OF TECHNOLOGY, SOUTH CAMPUS DEPARTMENT OF MCA INTERNAL TEST (SCHEME AND SOLUTION) II Subject Name: Advanced JAVA programming Subject Code: 13MCA42 Time: 11:30-01:00PM Max.Marks: 50M ) i)advantages of JSP: (3M) * Designing static pages using servlets require good knowledge of Java, but web designers may not be comfortable with Java programming constructs. * You need to recompile your servlet for every single change in the source code of the servlet. Whereas in JSP it is not required. * Servlets cannot be accessed directly and have to be mapped in the web.xml file, whereas JSP page can be accessed directly as a simple HTML page. * Programming in JSP is easier than in servlets because of tag based approach. Servlets require extensive coding. ii) Life Cycle of JSP: * Page Translation * Compilation * Loading and initialization * Request Handling * Destroying (EXPLANATION) (7M) 2) i) Implicit Objects: (2M) Implicit objects are certain pre-defined variables that can be included in JSP expressions and Scriplets. No need to instantiate. The JSP container automatically instantiates these objects. ii) Nine Implicit Objects: Request Response Out Page PageContext Application Session Config and Exception. (EXPLANATION) (8M) 3) Short Notes: i) <jsp:include> with <jsp:param>: (2M) * Allows a static or dynamic resource such as HTML or JSP page, specified by a URL to be included in the current JSP while processing the request.

2 * It can be a static call or dynamic call. Syntax: <jsp:include attributes> Attributes: 1) page: (e.g.) <jsp:include page= /header.html /> <jsp:include page= <%=mypath%> /> 2) flush: True or false (default) If true, the buffer is flushed before including the resource. If false, the JSP container continues to process the rest of the JSP page after the include action is completed. * Param Tag allows us to pass a name and value pair as parameter to dynamic resource or forwarding a request from a JSP page to another JSP page. (2M) Syntax: <jsp:param attributes> Attributes: 1) name 2) value Example: <jsp:include page= /page1.jsp > (1M) <jsp:param name= uname value= user1 /> <jsp:param name= usertype value= admin /> </jsp:include> ii) <jsp:plugin> Provides a easy support for including a Java applet or bean in the client web browser using a built-in or downloaded Java plug-in. (2M) Functions: * Specify whether the component added is a bean or an applet * Locate the code that needs to be run * Position the object in the browser window. * Specify a URL from which to download the plug-in software. * Pass parameter names and values to the object. <jsp:plugin attributes>..jsp.params and jsp.fallback tag. </jsp:plugin> Explanation of all attributes with example (3M) 4) i) Page Directive Tag: Defines attributes that notify the servlet engine about the general settings of a JSP page. The attributes are: (7M) ** language defines the scripting language to be used in page ** extends defines the class name of super class of servlet class that is generated from this JSP page ** buffer - Defines the size of the buffer used in the output stream.to direct the servlet to write output directly to the response output object <%@ page buffer="none" %> ** autoflush - Defines whether the buffer output is flushed automatically when the buffer is filled or whether an exception is thrown. The value is either true (automatically flush) or false (throw an exception). The default is true.

3 ` ** session - Defines whether the JSP page is participating in an HTTP session. The value can be either true (the default) or false. ** import - Defines the set of classes and packages that must be imported in the servlet class definition. The value of this attribute is a comma-delimited list of fully-qualified class names or packages. For example: import= java.sql.date,java.util.*,java.text.* ** info - Defines an informational string about the JSP page. ** contenttype - Defines the MIME type of the output stream. The default is text/html. ** pageencoding - Defines the character encoding of the output stream. The default is ISO ** iserrorpage - Defines that the JSP page has been designed to be the target of another JSP page s errorpage attribute. The value is either true or false(default). All JSP pages that are an error page automatically have access to the exception implicit variable. ** errorpage - Indicates another JSP page that handles all runtime exceptions thrown by this JSP page. The value is a URL that is either relative to the current web hierarchy or relative to the web application s context root. For example, errorpage= error.jsp (this is relative to the current hierarchy) or errorpage= /error/formerrors.jsp (this is relative to the context root) ii) include: (3M) * used to specify the names of the files to be inserted during the compilation of the JSP file. * The contents of the files so included become part of the JSP page. * The include directive can also be used to insert a part of the code that is common to multiple pages. (e.g.) <%@ include= bankheader.html %> 5) i) Java Beans: (3M) Reusable software components that separate the business logic from the presentation logic. JavaBeans are required to create effective and dynamic web pages by providing the benefit of using separate Java classes instead of embedding large amount of Java code directly in a JSP page. JavaBean uses getter and setter methods to invoke various methods explicitly to use their functionality with JSP pages.

4 ii) Program for verification of login page: (7M) Welcome.html <html><body> <form method="post" action="/seminar/link.jsp"> <p> Enter Username :<input type="text" name="username"> <br/> Password:<input type="password"name="password"> </p> <p><input type="submit" value="login"></p> </form> </body></html> link.jsp import="java.sql.*" contenttype="text/html" pageencoding="utf-8"%> <html> <head></head> <body> <% Connection con=null; String uname=request.getparameter("username"); String password=request.getparameter("password"); try Class.forName("com.mysql.jdbc.Driver"); con=drivermanager.getconnection ("jdbc:mysql://localhost:3306/t1","root",""); Statement st=con.createstatement(); ResultSet rs=st.executequery("select * from person where name=\""+uname+"\" and id=\""+password+"\""); if (!rs.next()) %> USER DETAILS GIVEN FOR UNAME: <%=uname%> NOT VALID <br/> TRY AGAIN <%@include file="login.html"%> </body> </html> <% return; finally trycon.close(); catch(exception e) %> THIS IS A HOME PAGE <br/>welcome, <%=uname%> </body></html>

5 6) Different ways of accessing the Bean Properties: (10M) setproperty tag: * sets the value of a property in a bean, using the bean s setter methods. * Before using this tag, the bean must be instantiated. Syntax: <jsp:setproperty attributes> Attributes: name: to set the properties of bean and to invoke property: takes the property name that has to be set and specifies the setter method that has to be invoked. Using * matches all the properties of a bean with the request parameters. value: Takes the value that has to be set to the specified bean property Accepts the value as the String type or as an expression that is evaluated at run time. Param: When setting bean properties from request parameters, it is not necessary that the bean has the same property names as the request parameters. getproperty Tag: * gets the value of a property in a bean by using the bean s getter method and writes the value to the current jspwriter. Syntax: <jsp:getproperty attributes> Attributes: 1) name: takes the reference variable name on which you want to invoke the getter method. 2) property: gets the value of a bean property and invokes the getter method of the bean property Example: <jsp:getproperty name= mybean property= uname /> 7) i) JAR Files: (5M) * JAR (Java Archive) is a package file format used to aggregate many java class files and associated metadata and resources (text, images, etc) into one file to distribute application software or libraries on the Java platform. * JAR files are fundamentally archive files, built on the ZIP file format and have the.jar extension. The basic format for creating a JAR file is Syntax: jar cf jar-file input-file(s) The basic format for viewing the contents of a JAR file is: Syntax: jar tf jar-file The basic format for extracting the contents of a JAR file is: Syntax: jar xf jar-file The basic format for adding files: Syntax: jar uf jar-file input-file(s)

6 ii) Annotations: (5M) * Allow to add metadata information (syntactic metadata) into the source code, although they are not part of the program itself. * Annotations were added to java from JDK 5. * No direct effect on the operation of the code they annotate. (does not affect the execution of the program). * When java source code is compiled, annotations will be processed by compiler plug-ins called annotation processors. Use of annotations: - Instructions to the compiler - Compile-Time instructors - Runtime instructions * An annotaion starts with the followed by the annotation name. * The indicates the compiler that it is an annotation * Annotations can be applied to the classes, interfaces, methods and fields. void mymethod() // Do something 8) i) Creating Packages: (5M) * Grouping of classes/interfaces together. * The grouping of classes/interfaces is usually done according to functionality. Packages act as containers for classes. Steps for creating packages: * Declare the package at the beginning of a file. * Define the class that is to be put in the package and declare it public. * Create a subdirectory under the main source files are stored. * Store the listing as the classname.java file in the subdirectory created. * Compile the file. This creates.class file in the subdirectory. package firstpackage.secondpackage ii) Interfaces: * An interface is a collection of abstract methods. * It can never be instantiated. * Doesn t contain any constructors or instance fields. The only fields that can appear in an interface must be declared both static and final. * Not extended by a class but it is implemented by a class. * An interface can extend multiple interfaces. Syntax:interface Interface_name // any number of final and static fields // any number of abstract method declarations (5M)

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