Introduction to JSP
- It stands for Java Server Pages.
- It is a server side technology.
- It is used for creating web application.
- It is used to create dynamic web content.
- In this JSP tags are used to insert JAVA code into HTML pages.
- It is an advanced version of Servlet Technology.
- It is a Web based technology helps us to create dynamic and platform independent web pages.
- In this, Java code can be inserted in HTML/ XML pages or both.
- JSP is first converted into servlet by JSP container before processing the client’s request.
- They are easy to maintain.
- No recompilation or redeployment is required.
- JSP has access to entire API of JAVA .
- JSP are extended version of Servlet.
- Coding in JSP is easy :- As it is just adding JAVA code to HTML/XML.
- Reduction in the length of Code :- In JSP we use action tags, custom tags etc.
- Connection to Database is easier :-It is easier to connect website to database and allows to read or write data easily to the database.
- Make Interactive websites :- In this we can create dynamic web pages which helps user to interact in real time environment.
- Portable, Powerful, flexible and easy to maintain :- as these are browser and server independent.
- No Redeployment and No Re-Compilation :- It is dynamic, secure and platform independent so no need to re-compilation.
- Extension to Servlet :- as it has all features of servlets, implicit objects and custom tags
Syntax available in JSP are following
- Declaration Tag :-It is used to declare variables.
- Java Scriplets :- It allows us to add any number of JAVA code, variables and expressions.
- JSP Expression :- It evaluates and convert the expression to a string.
- JAVA Comments :- It contains the text that is added for information which has to be ignored.
Syntax:- <%! Dec var %> Example:- <%! int var=10; %>
Syntax:- <% java code %>
Syntax:- <%= expression %> Example:- <% num1 = num1+num2 %>
Syntax:- <% -- JSP Comments %>
Steps for Execution of JSP are following:-
- Create html page from where request will be sent to server eg try.html.
- To handle to request of user next is to create .jsp file Eg. new.jsp
- Create project folder structure.
- Create XML file eg my.xml.
- Create WAR file.
- Start Tomcat
- Run Application
Example of Hello World
We will make one .html file and .jsp file
demo.jsp <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Hello World - JSP tutorial</title> </head> <body> <%= "Hello World!" %> </body> </html>
- It does not require advanced knowledge of JAVA
- It is capable of handling exceptions
- Easy to use and learn
- It can tags which are easy to use and understand
- Implicit objects are there which reduces the length of code
- It is suitable for both JAVA and non JAVA programmer
- Difficult to debug for errors.
- First time access leads to wastage of time
- It’s output is HTML which lacks features.