Using MongoDB from Java

This is an example of using Jedis to connect to the MongoHQ service from both a generic Java application and a Spring configured application on Heroku. Read more about how to use MongoHQ in the add-on article.

Using The Sample Code

Clone the repo with:

$ git clone https://github.com/heroku/devcenter-mongo-java.git

Start up MongoDB locally and set the MONGOHQ_URL environment variable:

$ export MONGOHQ_URL="mongodb://:@localhost:6379/dbname"

Build the sample:

$ mvn package
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building mongoSample 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
...

Now that it's built, you can run the plain Java example, or the Spring example:

• To run the plain Java example:

  $ sh target/bin/sample

• To run the Spring example:

  $ sh target/bin/spring-sample

Note: you can also use foreman to execute the Procfile. [Read more about foreman and procfiles](http://devcenter.heroku.com/articles/procfile).

You can switch between the Java and XML based configuration by commenting out one of the two lines in Main.java in the spring sub-package:

:::java
public class Main {

    public static void main(String[] args) throws Exception{

        // If you want Java based configuration:
        final ApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);
    
        // If you want XML based configuration:
        //final ApplicationContext ctx = new GenericXmlApplicationContext("applicationContext.xml");
    
        ...

Test on Heroku

Assuming you already have a Heroku account and have installed the Heroku command line tool, you can test this sample on Heroku in a few steps.

Create Heroku App

$ heroku create -s cedar
Creating quiet-waterfall-6274... done, stack is cedar
http://quiet-waterfall-6274.herokuapp.com/ | [email protected]:quiet-waterfall-6274.git
Git remote heroku added

Add Mongo HQ Service

$ heroku addons:add mongohq
-----> Adding mongohq to quiet-waterfall-6274... done, v1 (free)

Deploy Sample Using Git

$ git push heroku master
Counting objects: 62, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (45/45), done.
Writing objects: 100% (62/62), 11.52 KiB, done.
Total 62 (delta 12), reused 0 (delta 0)

-----> Heroku receiving push
-----> Java app detected
-----> Installing Maven 3.0.3..... done
-----> Installing settings.xml..... done
-----> executing /app/tmp/repo.git/.cache/.maven/bin/mvn -B -Duser.home=/tmp/build_31ktigwl5losz -Dmaven.repo.local=/app/tmp/repo.git/.cache/.m2/repository -s /app/tmp/repo.git/.cache/.m2/settings.xml -DskipTests=true clean install
       [INFO] Scanning for projects...
       [INFO]                                                                         
       [INFO] ------------------------------------------------------------------------
       [INFO] Building mongoSample 0.0.1-SNAPSHOT
       [INFO] ------------------------------------------------------------------------
       Downloading: http://s3pository.heroku.com/jvm/org/mongodb/mongo-java-driver/2.7.2/mongo-java-driver-2.7.2.pom
       Downloaded: http://s3pository.heroku.com/jvm/org/mongodb/mongo-java-driver/2.7.2/mongo-java-driver-2.7.2.pom (850 B at 2.1 KB/sec)
       Downloading: http://s3pository.heroku.com/jvm/org/springframework/spring-core/3.0.6.RELEASE/spring-core-3.0.6.RELEASE.pom
       Downloaded: http://s3pository.heroku.com/jvm/org/springframework/spring-core/3.0.6.RELEASE/spring-core-3.0.6.RELEASE.pom (3 KB at 17.6 KB/sec)
...

Execute the Sample Code as One-Off Processes

The two sample apps are listed as two process types, "sample" and "springsample". They are designed to be executed as one-off processes, so you execute them with

$ heroku run sample
Running sample attached to terminal... up, run.1
Launching MongoDB sample application.
Collections found in DB: [system.indexes, system.users]

and

$ heroku run springsample
Running springsample attached to terminal... up, run.2
Launching MongoDB sample application with Spring configuration.
Dec 1, 2011 11:40:14 PM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@6345e044: startup date [Thu Dec 01 23:40:14 UTC 2011]; root of context hierarchy
Dec 1, 2011 11:40:14 PM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@32b0bad7: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,springConfig,getDb]; root of factory hierarchy
Setting up new mongo client for connection mongodb://heroku:[email protected]:10055/app1797069
Collections found in DB (Spring Configuration): [system.indexes, system.users]