ServletConfig vs ServletContext

ServletConfig :

• One ServletConfig per servlet
• Used to pass deploy-time info to servlet and configured in deployment descriptor
• Used to access ServletContext
• Within servlet element in DD:
  

  <servlet>
  <display-name>InitParamTest</display-name>
  <servlet-name>InitParamTest</servlet-name>
  <servlet-class>
  test.InitParamTest</servlet-class>
  <init-param>
  <description>test parameter</description>
  <param-name>myname</param-name>
  <param-value>DummyValue</param-value>
  </init-param>
  </servlet>

• getServletConfig.getInitParameter(“myname”);
• Available to only to the servlet which has init-param configured

ServletContext:

• One per webapp
• If webapp is distributed, one per JVM
• Used to access webapp parameters configured in deployment descriptor
• Application bulletin-board
• Use to get server info
• Within web-app element of DD

• <context-param>
  <param-name>myname</param-name>
  <param-value>DummyValue</param-value>
  </context-param
  getServletContext.getInitParameter(“myname”);

• Avilable to any servlet or JSP that are part of webapp

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