Translation and compilation happens only once in a jsp. It is used to include any contents of files such as jsp file, html file or text file. So i have started another series on jsp tutorials and this is the first post of the series. Example of exception handling in jsp by the elements of page directive example of exception handling in jsp by specifying the errorpage element in web. Welcome instructor now lets take a look at the jsp directives. If the page has never been compiled, or if the jsp has been modified since it was last compiled, the jsp engine compiles the page.
Every jsp tag written in the page will be internally converted into an equivalent java code by the containers this process is called translation. Next jsp directives provide instructions to the jsp engine on how to handle jsp. If the servlet is older, the web container translates the jsp page into a servlet class and compiles the class. A servlet is a serverside program and written purely on java. I hope it helps you in understanding the basic concepts of jsps and help you in getting started. The translation and compilation obviously causes an initial delay for the first access. Jsp interview questions top jsp interview questions and answers. An introduction to xml and web technologies jsp programming. Directives messages to the jsp container in order to affect. Jsp directives provide instructions to the jsp engine to aid in the translation. Jsp are always compiled before they are processed by the server unlike. A static include means that the text of the included file is added to the jsp page. The include directive is used to includes a file during the translation phase.
In last few posts, a wrote a lot about java servlet and got very good response from our readers. Include a jsp file into another jsp file during the translation phase of jsp life cycle. Released in 1999 by sun microsystems, jsp is similar to php and asp, but uses the java programming language. Every time you change the jsp file, it will be recompiled again. Defines the scripting language to be used in the scriptlets, expression scriptlets, and declarations within the body of the translation unit the jsp page and any files included using the include directive below. The life cycle of a jsp page a jsp page services requests as a servlet. Jsp directives are used to give special instructions to the container while jsp page is getting translated to servlet source code. Hence, the code in expression tags would be compiled using java. Directive tag gives special instruction to web container at the time of page translation. Jsp implicit objects are created during the translation phase of jsp to the.
The life cycle of a jsp page brigham young university. Jsp directives page, include and taglib example journaldev. Home java java ee jsp directives page, include and taglib example jsp directives are used to give special instruction to container for translation of jsp to servlet code. If the page has never been compiled, or if the jsp has been modified since it was last compiled. Used to include text andor code at jsp page translationtime. Directives can have a list of attributes defined in keyvalue pairs and separated by commas. Translate texts with the worlds best machine translation technology, developed by the creators of linguee. The jsp specification is built on the top of the servlet api. The include directive is used to include the contents of any resource it may be jsp file, html file or text file. On the other hand, a web developer working independently can use java code and other jsp specific tags to code the business logic. This directive tells the container to merge the content of other external files with the current jsp during the translation phase. In this jsp tags are used to insert java code into html pages. They run in servlet containers such as tomcat or jetty.
You may code the include directives anywhere in your jsp page. Jsp directives are special instructions that are provided to the container software for the translation process. Java server page java servlet source code java servlet class file translator compiler generated servlets you can examine the source code produced by the jsp translation. Directive description defines pagedependent attributes, such as. Jsp interview questions and answers what is a jsp and what is it used for. Java server page is known as jsp is a technology for controlling the content or appearance of the web pages through the use of servlets, small programs that are specified on the web pages and run on the web server to change the web pages before it is sent to the user who has requested it. Directives and their attributes require a little more discussion. Translation and compilation during the translation phase each type of data in a jsp page is treated differently. Scripting elements let you specify java code that will become part of the resultant servlet, directives. This jsp in java online test is useful for beginners, freshers, experienced java developers, lecturers preparing for gate, job interview, university, semester exams, certification etc. Compilation of qrd decisions on stylistic matters in product information page 319 ema250902002 issues connected problems qrd suggestions conditional the translation of should causes problems in romance languages, czech, slovak, hungarian and croatian where its literal translations actually mean it would be preferable or it is. Each jsp page is internally translated into an equivalent servlet. Directives are used to control how the web container translates and executes the.
In jsp life cycle phase, jsp has to be converted to a servlet which is the translation phase. Jsp life cycle is defined as translation of jsp page into servlet as a jsp page. Your contribution will go a long way in helping us serve. This can be an importing java packages into jsp for processing java classes and method, enabling session for current jsp page, making thread safe, limiting buffer size. Jsp implicit objects are created during the translation phase of jsp to the servlet. Jsp directives are special instructionsthat are provided to the container softwarefor the translation process. The general usage form of this directive is as follows. Jsp stands for java server pages, it is a server side technology which is used for creating dynamic web pages.
When you use the include directive, the include process is static. The jsp directives are messages that tells the web container how to translate a jsp page into the corresponding servlet. Translation, initialization, execution, and finalization. When you deploy a web app with a jsp, the whole translation and compilation step happens only once in the jsp s life. Look up words and phrases in comprehensive, reliable bilingual dictionaries and search through billions of online translations. Pdf compilation translation execution srinivas poloju. After the first request, the file doesnt take long to load anymore.
According to this page information, jsp engine process further task. Directives in jsps are instruction from jsps to jsp engine. Jsp directives in this chapter, we will discuss directives in jsp. After the page has been translated and compiled, the jsp pages servlet for. Java server pages jsp is a serverside programming technology that enables the. The life cycle of a jsp page the java ee 5 tutorial. Refer this article for more detail on jsp declaration tag. The include directive is used to include a file during the translation phase. Pdf in chapter 24 the servlet technology was explained. Sep 07, 20 previous next jsp directives provide directions and instructions to the container, telling it how to handle certain aspects of jsp processing. This attribute is used to specify the scripting language for the current page. When a browser asks for a jsp, the jsp engine first checks to see whether it needs to compile the page. The jsp container interprets the standard directives and actions, and the custom. Thus, the life cycle and many of the capabilities of jsp pages in particular the dynamic aspects are determined by java servlet technology.
The include directive includes the original content of the included resource at page translation time the jsp page is translated only once so it will be better to include static resource. The directives that pertain to buffering output and handling errors are discussed here. This is known as static include because the target page is located and included at the time of page compilation. Jsp is the view in mvc approach for showing output.
Jsp scriptlet, declarations, expression, comments, directive. The compiled pages, as well as any dependent java libraries, contain java. Jsp directive allow us to define our page information of jsp and translate these information to jsp engine. Jsp technology makes available all the dynamic capabilities of java. Jsp in java objective type questions with answers and explanation mcqs for job interview and placement tests. Feb 23, 2017 jsp scriptlet, declarations, expression, comments, directive and actions like us on facebook java server pages classes jsp. The included file can be a jsp page, html file, xml document, or text file. Jsps are translated into servlets at runtime, therefore jsp is a servlet. They provide global information about an entire jsp page. A jsp directive affects the structure of the servlet class. In another way, we can say that jsps are extension of servlets to minimize the effort of developers to write user interfaces using java programming. A web designer can design and formulate the layout for the web page by using html. The semantics of scripting elements are easy to understand.
Compilation of qrd decisions on stylistic matters in. During development, one of the advantages of jsp pages over servlets is that the build process is performed automatically. Directives are used to control how the web container translates and executes the jsp page. Jsp directive elements the directive elements are used to do page related operation during page translation time. A a jsp declaration tag is used for declaring variables and methods so that you can use them later on a jsp page based on the requirement. Javaserver pages jsp technology allows you to easily create web content that has both static and dynamic components. It is used to include some other pages into the jsp document, it may be jsp file, html file or text file. If a jsp is implemented using a compiler or translator, the directives can be seen as providing information for the compilationtranslation phase. The include occurs only when the servlet implementing the jsp page is being built and compiled.
Java servlet pdf tutorial serving pdf from java servlet. Every jsp tag written in the page will be internally converted into an equivalent java code by the containers this process is called translation there are two phases are occurs in jsp. Jsps are normal html pages with java code pieces embedded in them. Javaserver pages jsp is a collection of technologies that helps software developers create dynamically generated web pages based on html, xml, soap, or other document types. We know by now that the container is responsiblefor converting that jsp into a servlet file,and whilst this conversion takes place,directives are those components inside your jsp pagewhich will relay. The purpose of the contenttype directive is to allow the browser to correctly interpret the resulting content. It is a web based technology helps us to create dynamic and platform independent web. Jsp scripting elements topics in this chapter the purpose of jsp. In jsp, we can use many tags such as action tags, jstl, custom tags, etc. The jsp is first translated into java source code, and if there are no translation errors, it is then compiled into a servlet class file. Jsp technology has facilitated the segregation of the work of a web designer and a web developer. For details, see your servers documentation or section 1. In the translation phase, jsp engine checks for the jsp syntax and translates jsp page into its page implementation class if the syntax is correct.
Java server pages jsp is a platform independent presentation layer technology that comes with sun s j2ee platform. Modernday java web development uses frameworks that are built on top of servlets. The complete reference phil hanna osbornemcgrawhill new york chicago san francisco lisbon london madrid mexico city milan new delhi san juan seoul singapore sydney toronto. Jsp is a web server side programming technology based on servlet technology. A there are three types of directives available in jsp. You may code include directives anywhere in your jsp page. Jsp directives are the elements of a jsp source code that guide the web container on how to translate the jsp page into its respective servlet.
You can even include nonxml jsp content in xmlstyle comments, and it will be treated as part of comments, i. Jsp is slower than servlet because the first step in jsp lifecycle is the translation of jsp to java code and then compile. Exception handling session management directives jsp with java bean jdbc. Compilation process of jsp page involves three steps. Static data is transformed into code that will emit the data into the response stream. Jsp directives java, jsp, tomcat, web server, tutorials. To compile this java code using jdk, use d option to put the compiled class into. Jsp directives are used to give special instruction to a container for translation of jsp to servlet code. The page directive provides a mechanism to define attributes for a jsp page.