web-student-tracker

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Student DB Utility

• Responsible for interfacing with the database using JDBC code
• This is a common design pattern: Data Accessor Object (DAO

Create a Database Application

Class Project

• Fill working JSP and Servlet application that connects to a database

Road Map

• Set up Database Dev Environment
• List Student
• Add a new Student
• Update a Student
• Delete a Student

Setup Tomcat Database Connection Pool

Database Connection in Web Apps

• You may think you need a single database connection...
  • Will mot scale for multiple web users

This will not scale for multiple users.
For example: you have a large number of users, and they all want to make use of one telephone. So, your office only has one telephone and you have 40 or 50 people and they need to make use of the telephone to make a phone call. So, this wouldn't work out. You'll have along queue and people will wait to actually use the telephone. So, we need to have a solution for this. So, the best practice in the industry is to make sure of database connection pools.

Database Connection Pools

• Best practice is to use database connection pools
  • Allows your app to scale and handle multiple users quickly

+ This will allow your app to scale and handle multiple users quickly.

Database Connection in Tomcat

1. Download JDBC Driver JAR file
   • Place the JAR file in your app's WEB-INF/lib
2. Define connection pool in META-INF/context.xml

File: WebContent/META-INF/context.xml

 <Context>

    <Resource name="jdbc/student_tracker"
              auth="Container" type="javax.sql.DataSource"
              maxActive="20" maxIdle="5" maxWait="10000"
              username="webstudent" password="webstudent"
              driverClassName="org.postgresql.Driver"
              url="jdbc:postgresql://localhost:3306/web_student_tracker"/>

</Context>

• This is a Tomcat specific file that basically tells Tomcat how to connect to database and how to configure connection pool
  • Such as how many connections to create up front, the minimum numbers of connections, etc...
• name="jdbc/student_tracker" is the alias that is used in application to look up this connection pool.
• auth="Container" means authenticate auth="Container" means Tomcat server will handle the authentication
• type="javax.sql.DataSource" The actual name of java interface that is use for communication with pool.
  • In the java world, DataSource is generic term for you connection pool.
• maxActive="20" maxIdle="5" maxWait="10000" are Size configuration.
  • maxActive="20" means we're going to have 20 connections in our pool.
  • maxIdle="5" means if there are no users in our system, at least 5 connections are available.
  • maxWait="10000" is time in milliSeconds as for as how long someone can wait before they get a connection.

3. Get connection pool reference in Java code
   • Leverage resource injection with the Servlets
   • This means that Tomcat will AUTOMAGICALLY
     • Set the connection pool / datasource on your servlet

Configuring jdbc-pool for high-concurrency

• https://my.oschina.net/shipley/blog/519449

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Real-World Tips and Tricks to Tune Apache Tomcat for High Performance

• https://www.eginnovations.com/blog/tomcat-performance-tuning/

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Optimal number of connections in connection pool

• http://stackoverflow.com/questions/1208077/optimal-number-of-connections-in-connection-pool

Add Student

Sequence Diagram

Update Student

Action Link - Update

Sequence Diagram

Delete Student

Action Link - Update

Sequence Diagram

Add Search features to the App

Basically, we will allow the user to search for a customer by name. We'll add a search box at to the screen and the user can enter a name. On the backend, we'll compare this name to the customer's first name or last name.

Overview of Development Process

1. Create the HTML form
2. Add routing logic in StudentControllerServlet
3. Add method in the StudentDbUtil to perfom search