Question

Fill in the blanks in each of the following statements: a) JSP action ______ enables an applet or JavaBean to be added to a Wcb page in the form of a browser-specific object or embed XHTML element. b) Action ______ has the ability to match request parameters to properties of the same name in a bean by specifying \(^{* *}\) is are property. c) There are four key components to JSPs: ______, ______, ______, and ______. d) \(A\) JSP can include a custom tag library with the ______ directive. e) The implicit objects have four scopes: ______, ______, ______, and ______. f) The ______ directive is processed once, at JSP translation time and causes content to be copied into the JSP. g) Classes and interfaces specific to JavaServer Pages programming are located in packages ______ and ______. h) JSPs normally execute as part of a Web server that is referred to as the ______ i) Method ______ can be called repeatedly to process the body of a custom tag. j) JSP scripting components include ______, ______, ______, ______, and ______.

Short answer

a) b) c) directives, scriptlets, expressions, declarations d) e) page, request, session, application f) g) javax.servlet.jsp, javax.servlet.http h) servlet container i) doBody() j) scriptlets, expressions, declarations, directives, comments.

Step-by-step solution

Identify Missing Statements

Read through each incomplete statement and identify what type of information is being asked for, such as an action, directive, or component.

Understand JSP Concepts

Recognize basic JSP concepts related to actions, directives, tags, and implicit objects. Have knowledge about how JSP integrates with web servers and Java packages.

Complete Statement (a)

The JSP action enables an applet or JavaBean to be added to a web page in the form of a browser-specific object or embed XHTML element.

Complete Statement (b)

The action has the ability to match request parameters to properties of the same name in a bean by specifying '*' (wildcard) as a property.

Complete Statement (c)

There are four key components to JSPs: directives, scriptlets, expressions, and declarations.

Complete Statement (d)

A JSP can include a custom tag library with the directive.

Complete Statement (e)

The implicit objects have four scopes: page, request, session, and application.

Complete Statement (f)

The directive is processed once at JSP translation time and causes content to be copied into the JSP.

Complete Statement (g)

Classes and interfaces specific to JavaServer Pages programming are located in packages javax.servlet.jsp and javax.servlet.http.

Complete Statement (h)

JSPs normally execute as part of a Web server that is referred to as the servlet container.

Complete Statement (i)

Method doBody() can be called repeatedly to process the body of a custom tag.

Complete Statement (j)

JSP scripting components include scriptlets, expressions, declarations, directives, and comments.

Key concepts

JSP actions

JSP actions are essential elements of JavaServer Pages that allow developers to encapsulate the functionality they want to add to their web applications. These actions use specific XML tags to control the behavior of the server. For example, the `` action enables an applet or JavaBean to be embedded in the form of a browser-specific object or an XHTML element. This allows for a versatile way of integrating dynamic content.

JSP actions can also manage JavaBean components, which are reusable software components that follow certain conventions. The `` action tag is used to set property values in JavaBeans, often matching request parameters with bean properties. This dynamic association simplifies data handling in web applications.

Some common JSP actions include:

• `` - Includes content from another source.
• `` - Forwards the request to another resource.
• `` - Declares a JavaBean for use in the JSP.

JSP actions help to streamline the development process by allowing developers to integrate complex processes and components efficiently.

JSP directives

JSP directives provide global information to the JSP container and affect the overall structure of the resulting servlet class. They are crucial for configuring how the JSP page is compiled and executed. There are three primary directives:

• `<%@ page %>` - Defines attributes that apply to the entire JSP, like language, error pages, or buffer size.
• `<%@ include %>` - Incorporates a file into the JSP at translation time. This means that the content of the file is merged into the JSP before it is compiled.
• `<%@ taglib %>` - Allows the use of custom tag libraries within a JSP. This directive specifies the URI of the library and the prefix used to access its tags.

Directives are processed only once when the JSP is translated into a servlet, making them a critical part of setting up the environment and behavior for JSP execution.

For managing repetitive code and ensuring consistency, directives are an indispensable tool in a JSP developer's toolkit.

JSP implicit objects

In JSP, implicit objects are pre-created objects that developers can use to perform common tasks without the need to define them manually. These objects simplify interaction with client requests, responses, and application contexts. Here are the most commonly used implicit objects:

• `request` - Represents the client's request and provides data from HTTP headers.
• `response` - Used to formulate HTTP responses and manage output data to the client.
• `session` - Manages user session data, useful for storing user-specific data across requests.
• `application` - Shares data among all users of the application, represented as a global context.
• `out` - Used to send content to the client, typically HTML.

The four scopes of implicit objects, page, request, session, and application, determine how data is shared and persisted across different areas of the web application.

These objects are automatically available and ready to use, which allows for rapid development. Utilizing implicit objects effectively can lead to cleaner, more efficient code and reduced development time.

JSP scripting components

JSP scripting components are tools that allow developers to write Java code directly into their JSP pages. These are scriptlets, expressions, declarations, directives, and comments. Each scripting component serves a specific purpose:

• **Scriptlets** - Insert Java code that is executed during the request, enclosed in `<% ... %>`. They bring dynamic behavior by allowing Java logic to be embedded within HTML.
• **Expressions** - Simplify output by letting developers inject Java values into content using `<%= ... %>`.
• **Declarations** - Allow the definition of methods or fields that become part of the final servlet, using `<%! ... %>`. This is helpful for reusability and modularity.
• **Directives** - Already discussed above, hint the compiler on how to handle the page.
• **Comments** - Include developer notes that aren't visible to the client, using `<%-- ... --%>`.

Scripting components augment the static content of a page with Java's dynamic capabilities. While they offer flexibility, it's generally encouraged to minimize their use in favour of using tag libraries and beans to maintain clear separation between business logic and presentation.