Servlet By Prof B A Khivsara Note The

Servlet By Prof. B. A. Khivsara Note: The material to prepare this presentation has been taken from internet and are generated only for students reference and not for commercial use.

What are Servlets? • Java Servlets are programs that run on a Web or Application server and act as a middle layer between a requests coming from a Web browser or other HTTP client and databases or applications on the HTTP server. • Using Servlets, you can collect input from users through web page forms, present records from a database or another source, and create web pages dynamically.

Advantages of Servlet over CGI • Performance is significantly better. • Servlets execute within the address space of a Web server. It is not necessary to create a separate process to handle each client request. • Servlets are platform-independent because they are written in Java. • servlets are trusted. • The full functionality of the Java class libraries is available to a servlet.

Servlets Architecture

Servlets Packages • Java Servlets are Java classes run by a web server that has an interpreter that supports the Java Servlet specification. • Servlets can be created using the packages • javax. servlet. http

Requirements Before running Servlet your machine requires following tools • 1> Eclipse (IDE-integrated development environment) • 2> Tomcat (Web Server)

How to configure tomcat server in Eclipse ? (One time Requirement) • If you are using Eclipse IDE first time, you need to configure the tomcat server First. • For configuring the tomcat server in eclipse IDE, • click on servers tab at the bottom side of the IDE -> right click on blank area -> New -> Servers -> choose tomcat then its version -> next -> click on Browse button -> select the apache tomcat root folder previous to bin -> next -> add. All -> Finish.

How to configure tomcat server in Eclipse ?

Steps to run servlet in Eclipse Create a Dynamic web project create a servlet add servlet-api. jar file Run the servlet

Create the dynamic web project Start Eclipse and In Menu : File -> New -> Dynamic Web Project

Create the dynamic web project

Create the dynamic web project Structure of Dynamic Web Project

Steps to run servlet in Eclipse Create a Dynamic web project create a servlet add servlet-api. jar file Run the servlet

Create a servlet Right click on Src -> New -> Sevlet

Create a servlet Give name of class

Create a servlet

Create a servlet Either select do. Get or do. Post

Create a servlet Servlet is created, you can write the code now.

Steps to run servlet in Eclipse Create a Dynamic web project create a servlet add servlet-api. jar file Run the servlet

Add servlet-api. jar file

Add servlet-api. jar file In Tomcat folder goto Lib folder and select servlet-api. jar file

Add servlet-api. jar file

Steps to run servlet in Eclipse Create a Dynamic web project create a servlet add servlet-api. jar file Run the servlet

Run the servlet Right click on project name -> click Run As -> Run on Server

Run the servlet

Example 1 To Print Hello World directly import java. io. *; import javax. servlet. http. *; public class Hello. World extends Http. Servlet { public void init() throws Servlet. Exception { } public void do. Get(Http. Servlet. Request request, Http. Servlet. Response response) throws Servlet. Exception, IOException { response. set. Content. Type("text/html"); Print. Writer out = response. get. Writer(); out. println("<h 1> Hello World </h 1>"); } public void destroy() { } }

Reading Form Data using Servlet • get. Parameter() − You call request. get. Parameter() method to get the value of a form parameter. • get. Parameter. Values() − Call this method if the parameter appears more than once and returns multiple values, for example checkbox. • get. Parameter. Names() − Call this method if you want a complete list of all parameters in the current request.

Example 2 To read data from HTML file and print that. • It requires 2 files: • 1. HTML (s 1. html)File • 2. Servlet (s 2. java) File • First Run HTML file and after clicking on submit button it will run servel(. java) file.

Example 2 To read data from HTML file and print that. • S 1. html (html code) <html> <form method=“post” action=“s 2”> Enter Your Name <input type=text name=“t 1”> <input type=“submit” value=“submit”> </form> </body> </html>

Example 2 To read data from HTML file and print that. • S 2. java (Servlet Code) import java. io. *; import javax. servlet. *; public class s 2 extends Http. Servlet { public void do. Post(Http. Servlet. Request request, Http. Servlet. Response response) throws Servlet. Exception, IOException { response. set. Content. Type("text/html"); String a= request. get. Parameter("t 1"); Print. Writer out= response. get. Writer(); out. print(" Your Name is: "+a); } }

Example 3 – (HTML code) To read data from HTML checkbox values print that • • • <!DOCTYPE html> <html> Name of Servlet File <body> <form method="post" action=s 1> Hobbies <input type="checkbox" name="t 1" value=“Cricket"> Cricket <input type="checkbox" name="t 1" value="Music">Music <input type="checkbox" name="t 1" value=“Dance">Dance <input type="submit" value="submit"> </form> </body> </html>

Example 3 – (servlet code) To read data from HTML checkbox values print that • protected void do. Post(Http. Servlet. Request request, Http. Servlet. Response response) • throws Servlet. Exception, IOException { • response. set. Content. Type("text/html"); • Print. Writer out=response. get. Writer(); • String[] values=request. get. Parameter. Values("t 1"); • • for(int i=0; i<values. length; i++) • { • out. println("<li>"+values[i]+"</li>"); • } • }

References • https: //www. javatpoint. com/servlet-tutorial • https: //www. tutorialspoint. com/servlets/index. htm • https: //www. tutorialspoint. com/servlets-firstexample. htm • https: //www. javatpoint. com/creating-servlet-in-eclipse-ide