150 ServletContext Attribute how to send the data between two different web resource programs java

java Web Application to understand ServletContext Attributes how to pass/send the data between two different web resource programs of java web application using ServletContext Attributes:
ServletContext Attributes:
(Third way : how to pass/send the data between two different web resource programs of java web application using ServletContext Attributes)
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- ServletContext Object is one per java web application and it is resides in the global memory of the web appln.

- ServeltContext attributes allocates memory in Serlvet Context object and they are visible in all the web resource programs of java web application irrespective of the request , response object(either they are in chaining or not) they are using & irrespective of the browser window form which they are getting request. (either from same browser window or different browser windows)

- in this diagram ServletContext object and servletcontext attributes are created in Srv1 Servlet Program is visible and accessible in all the web resource programs of java web appln without any condition / unconditionally.

- ServletContext attributes scope is application scope that means they are visible throught the web application across the multiple request.

- SevletContext object is also called as "Application" object so we can call ServletContext attributes as "Application attributes".

- To create ServletContext object, attributes:
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ServletContext sc=getServletContext(); //gets access to servletContext object
sc.setAttribute("email","[email protected]");
sc.setAttribute("age",29);

- To modify ServletContext attributes:
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sc.setAttribute("email","[email protected]");
sc.setAttribute("age",60);

- To read/access ServletContext attributes:
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String m=(String)sc.getAttribute("email");
int ageVal=(Integer)sc.getAttribute("age");

- To remove ServletContext attributes:
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sc.removeAttribute("email");
sc.removeAttribute("age");


Example java Web Application to understand ServletContext Attributes how to pass/send the data between two different web resource programs of java web application using ServletContext Attributes:
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51ServletContextScopeAttribute: (DDS)
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|
|-----WEB-INF
|--------web.xml
|--------classes
|--------Srv1.java
|--------Srv2.java
|--------Srv3.java
|--------Srv4.java
|--------*.class

Compile all the servlets

Deploy the 51ServletContextScopeAttribute web appln in tomcat server (Copy & Paste 51ServletContextScopeAttribute folder to webapp folder of tomcat)

- Start the Tomcat Server

- Test the web application (Browser Window)
http://localhost:2020/51ServletContextScopeAttribute/s4url

http://localhost:2020/51ServletContextScopeAttribute/s1url
http://localhost:2020/51ServletContextScopeAttribute/s2url
http://localhost:2020/51ServletContextScopeAttribute/s3url


Do Observe the output.