Скачать или смотреть 93 Servlet to Database software communication using ServletConfig init parameter from web.xml file

Example application on #Servlet to #Database software #communication using #ServletConfig init parameter from #web.xml file: #Advance #Java #Servlet #Programming #Tutorial
To make our servlet program as flexible program to modify dont hardcode any details in servlet program that are changeable in the future.

That are recommeded to pass these changeable details to servlet program from outside of the servlet program by using one of the follwing two ways.

1) As request parameter values (From Data):
-------------------------------------------
End user supplies these values as non-technical values from client side(Browser window)

Eg: Name, age, address, & etc ... values

To read these values in our servlet program we need reqest.getParameter("id");

2) As Servlet init parameter values (from web.xml)
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Programmer supplies these values as technical values from server side.
Eg: JDBC driver class name, JDBC URL, Database username, Databse password......

To read these values in our servlet program we need to use ServletConfing object like cg.getInitParameter("-") method.

To make JDBC code of servlet program as flexile code to modify it recommended to gather JDBC properties like Driver class name, URL, DB username, password from outside of the servlet program, since JDBC properties are technical values/info so, only programmer can pass them as servlet init parameter values from web.xml file.

(for security reason we may need to pass database username, password may time-to-time change in real-time because of that reason we need to pass technical values from web.xml file as out side of servlet program as servlet init parameter) and also no need to recompile the source code by end user/programmer & directly we can execute.

Deployment Directory Structure:
---------------------------------

30DBAppSservletConfig
---------------------
|
|----input.html
|----WEB-INF
|
|-------web.xml
|-------lib
|
|------ojdbc14.jar
|------classes
|
|------DBSrv.java
|------DBSrv.class

input.html
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