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02/10/2016 Categories: Servlets. No Comments on Initialization Parameters in Servlets

Most of the time, data (Ex: admin email, database username and password, user roles etc…) need to be provided in the production mode (client choice). Initialization parameters can reduce the complexity and maintenance. Initialization parameters are specified in the web.xml file as follows:

 

Initialization parameters are stored as key value pairs. They are included in web.xml file inside init-param tags. The key is specified using the param-name tags and value is specified using the param-value tags.

 

Servlet initialization parameters are retrieved by using the ServletConfig object. Following methods in ServletConfig interface can be used to retrieve the initialization parameters:

  • String getInitParameter(String  parameter_name)
  • Enumeration getInitParameterNames()

 

Following example demonstrates initialization parameters:

login.html

 

web.xml

 

ValidServ.java (Servlet file)

 

In the above example four pairs of initialization parameters are stored in web.xml file. In the servlet file we are validating the username and password entered in the login page against the initialization parameters by retrieving them from web.xml file.

 

In the above example four pairs of initialization parameters are stored in web.xml file. In the servlet file we are validating the username and password entered in the login page against the initialization parameters by retrieving them from web.xml file.

 

Video: Initialization Parameters

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