nivas90 / database-course-projects

Code examples for CS6360 Database Design course.

Code examples for CS6360 Database Design course. It contains following projects

1. tasks-jdbc
   • Implements interaction with database using JDBC
2. tasks-spring
   • Implements interaction with database using JdbcTemplate and usages DAO and Domain objects.
3. servlet-jsp-hello-world
   • Simple servlet and jsp project, demonstrating how to create web application
4. tasks-spring-mvc
   • Fully functional Spring MVC application for managing tasks and task-items.

Requirements

• Apache Maven, project management and build tool
• Apache Tomcat, servlet container for deploying web application

Installing Maven

Refer to http://maven.apache.org/download.cgi#Installation. Generally the process is simply extract the compressed binary file and setup few environment variables.

Installing Tomcat

Refer to http://tomcat.apache.org/tomcat-7.0-doc/setup.html#Introduction. Generally the process is simply extract the compressed binary file, setup few environment variables, assign ports those are not used, and run the startup script.

Configuring Tomcat

As we are going to deploy our web applications via maven, we need to change few configurations. For tomcat version 7.x, add the following in $TOMCAT_HOME/conf/tomcat-users.xml in <tomcat-users> tag.

<role rolename="manager-gui"/>
<role rolename="manager-script"/>
<user username="tomcat" password="tomcat" roles="manager-gui, manager-script"/>

This will create a manager user with name tomcat and password tomcat.

Pre processing for building code

• For database interacting projects like tasks-jdbc, tasks-spring, and tasks-spring-mvc, copy src/main/resources/jdbc-sample.properties to src/main/resources/jdbc.properties and fill up four attributes.

• For web applications like tasks-spring-mvc and servlet-jsp-hello-world copy tomcat-sample.properties to tomcat.properties and fill up all the variables. For example

    tomcat.username=tomcat
    tomcat.password=tomcat
    tomcat.manager_url=http://localhost:8080/manager/text
  

Build and Run

Project tasks-jdbc and tasks-spring are terminal based application. For these two

To compile

mvn compile 

To clean and compile

mvn clean compile

To execute -

mvn exec:java -Dexec.mainClass="class-path-to-main"  -Dexec.args="arg0 arg1 arg2"

Here, class-path-to-main is fully qualified class path to a class containing to public static void main(String []args) method. and arg0 arg1 arg2 are arguments passed to main method.

For example executing PreparedStatementExample in tasks-jdbc project -

$ cd tasks-jdbc
$ mvn exec:java -Dexec.mainClass="edu.utd.dspl.tasks.PreparedStatementExample" 

Project servlet-jsp-hello-world and tasks-spring-mvc are web application.

To clean and compile

mvn clean compile

To build war file

mvn package 

To deploy, (assuming tomcat is configured properly)

mvn tomcat:deploy 

To undeploy, (assuming tomcat is configured properly)

mvn tomcat:undeploy

In addition, this project can be directly executed from any modern IDE like Intellij IDEA, Eclipse, Netbeans, etc.

Ideas that these examples don't cover

• Session
• Spring Security
• Property editor
• Logging
• Exception handling

Common problems with spring and tomcat

Problem: Ran out of permgen space, getting exception.

org.springframework.web.util.NestedServletException: Handler processing failed; nested exception is java.lang.OutOfMemoryError: PermGen space

Solution:

Increase permgen space of tomcat. Add the following system variable or add the following line in catalina.sh of Apache Tomcat.

CATALINA_OPTS="-Xmx1024m -XX:MaxPermSize=512m"