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https://github.com/csev/maven-jetty-jdbc-servlet

A simple servlet that uses Maven, JDBC, and Jetty to say 'Hello world'
https://github.com/csev/maven-jetty-jdbc-servlet

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A simple servlet that uses Maven, JDBC, and Jetty to say 'Hello world'

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README 

        

A simple servlet that uses Maven, JDBC, and Jetty to say 'Hello world'



Setup The Database

------------------



First, make a database, user, table and add a record:



    CREATE DATABASE mjjs DEFAULT CHARACTER SET utf8;

    GRANT ALL ON mjjs.* TO 'mjjsuser'@'localhost' IDENTIFIED BY 'mjjspassword';

    GRANT ALL ON mjjs.* TO 'mjjsuser'@'127.0.0.1' IDENTIFIED BY 'mjjspassword';

    CREATE TABLE mjjs (name TEXT) ENGINE = InnoDB DEFAULT CHARSET=utf8;

    INSERT INTO mjjs (name) VALUES ('tsugi');



If you have changed any of the values in the example SQL above, edit

the file `src/main/resources/application.properties` and edit these

properties:



    mjjs.datasource.url=jdbc:mysql://localhost:8889/mjjs

    mjjs.datasource.username=mjjsuser

    mjjs.datasource.password=mjjspassword

    mjjs.datasource.driverClassName=com.mysql.jdbc.Driver



Build / Run

-----------



    mvn clean compile install jetty:run



Then navigate to 



    http://localhost:8080/mjjs/hello



If you get this message:



    Reading /application.properties ...

    Your database is missing or inaccessible



Fire up MAMP, go to localhost:8888/phpMyAdmin, click on SQL tab and

copy paste these lines of SQL into the text box and hit "Go"



    CREATE DATABASE mjjs DEFAULT CHARACTER SET utf8;

    GRANT ALL ON mjjs.* TO 'mjjsuser'@'localhost' IDENTIFIED BY 'mjjspassword';

    GRANT ALL ON mjjs.* TO 'mjjsuser'@'127.0.0.1' IDENTIFIED BY 'mjjspassword';



Refresh the phpMyAdmin page, and mjjs now appears on the left.

Click on the mjjs database and then click on the SQL tab. 

Copy paste this command into the text box and hit go



    CREATE TABLE mjjs (name TEXT) ENGINE = InnoDB DEFAULT CHARSET=utf8;

    INSERT INTO mjjs (name) VALUES ('tsugi');



Refresh this page: http://localhost:8080/mjjs/hello



If all goes well, you will see output like the following:



    Welcome to hello world!

    Reading /application.properties ...

    name=tsugi

    Successfully read 1 rows from the database



Looking at the Source Code

--------------------------



* The [`pom.xml`](https://github.com/csev/maven-jetty-jdbc-servlet/blob/master/pom.xml) file controls the build process - it tells `mvn` where the source files 

are located and what output files to produce.  It also tells `mvn` to download library code

for the declared code libraries that this application "depends on".



* The [`src/main/java/mjjs/HelloServlet.java`](https://github.com/csev/maven-jetty-jdbc-servlet/blob/master/src/main/java/mjjs/HelloServlet.java) contains the source code for our Java Servlet.

If you look at the code, you will see methods for doGet() and doPost() - these methods are

called when there is a GET or POST to the application's URLs.  It defines a class called

`mjjs.HelloServlet` that is referenced in the next file.   You can debug this program by 

adding calls to `System.out.println()` and those print statements will come out on your console.



* The [`src/main/webapp/WEB-INF/web.xml`](https://github.com/csev/maven-jetty-jdbc-servlet/blob/master/src/main/webapp/WEB-INF/web.xml) file tells the servlet container ([Jetty](http://www.eclipse.org/jetty/) in this case)

which URLs are to be handed to which classes.  If you lok at this file, it has two 

sections - one defines a servlet and maps it to the java class and the other takes a URL

pattern and indicates that it needs to be sent to a particular servlet (i.e. which Java class).



    

Background Documentation to Read

--------------------------------



These are some online resources to read that explain how things in this servlet works:



* [How to Write a Hello World Servlet](http://stackoverflow.com/questions/18821227/how-to-write-hello-world-servlet-example)

* HttpServlet interface - [javax.servlet.http.HttpServlet](http://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServlet.html)

* Request Object interface - [javax.servlet.http.HttpServletRequest](http://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html)

* Response Object Interface - [javax.servlet.http.HttpServletResponse](http://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletResponse.html)

* [Lesson: JDBC Basics](https://docs.oracle.com/javase/tutorial/jdbc/basics/)

* Database Connection interfaces - [java.sql](http://docs.oracle.com/javase/7/docs/api/java/sql/package-summary.html)



Errors

------



If you end up with this error, 



    No plugin found for prefix 'jetty' in the current project and in the

    plugin groups [org.apache.maven.plugins, org.codehaus.mojo] available

    from the repositories