Java Servlets: Different kinds of attributes

Question

Was going through some Java Servlets code.

I found attributes set and retrieved in 3 different ways.

req.getSession().setAttribute("var1","value1"); 
req.setAttribute("var2", "value2"); 
getServletContext().setAttribute("var3", "value3");

req is a variable of type HttpServletRequest I am a little confused as to what is the difference between the three?

They set the attribute in session, request, or servlet context scope respectively. — Henry, Nov 07 '16 at 10:56

Mandar Pandit · Accepted Answer · 2016-11-07T11:09:22.640

2

req.getSession().setAttribute("var1","value1"); - Is a Session Attribute.

req.setAttribute("var2", "value2"); - Is a Request Attribute.

getServletContext().setAttribute("var3", "value3"); - Is a Servlet Context Level (an Application) Attribute.

edited Nov 07 '16 at 11:09

answered Nov 07 '16 at 10:56

Mandar Pandit

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score 1 · Answer 2 · answered Nov 07 '16 at 10:55

The first one is a session attribute, the second one is a request attribute and the third one is an attribute belonging to the ServletContext.

If you don't know what the session is and how it differs from the request, you should be studying how HTTP works.

The ServletContext is a separate place for the server to keep certain information. You'd more often be getting the attributes from there, rather than setting them.

Java Servlets: Different kinds of attributes

2 Answers2