PostgreSQL

Wildfly – PostgreSQL Driver Install

AlexBLeave a comment
  1. Environnement:
    • Wildfly 10
    • Java JDK 8.xx
    • Postgresql 9.4
  2. Download Postgresql driver. See: https://jdbc.postgresql.org/download.html
  3. Run ./jboss-cli.sh from wildfly/bin
  4. From jboss-cli command-line:
    connect

#add module
module add --name=org.postgres --resources=/tmp/postgresql-9.4.1207.jar --dependencies=javax.api,javax.transaction.api

# add driver to subsystem datasources
/subsystem=datasources/jdbc-driver=postgres:add(driver-name="postgres",driver-module-name="org.postgres",driver-class-name=org.postgresql.Driver)

# declare datasource: here: server is on localhost, and db is postgres_db
# username is postgres and password is posgres
data-source add --jndi-name=java:jboss/datasources/PostGreDS --name=PostgrePool --connection-url=jdbc:postgresql://localhost/postgres_db --driver-name=postgres --user-name=postgres --password=postgres

Getting Started: EJB/Persistence (with PostgreSQL)

AlexBLeave a comment

[DRAFT… To be continued …] last update: Feb 4th

I’ve been using PHP (especially Symfony 2.x) for quite a while in my web projects (both backend and frontend), coupled with MongoDB.

Almost a year ago, I’ve discovered that PostGreSQL supports “JSON/JSONB” and handles “requests” over Json/JsonB. Couple of months ago, I had a project involving OptaPlanner, so I had to move to J2EE world, and it not so worst.

A month ago, I started a project (on my free time) from scratch to deeply evaluate pros/cons of EJB/JPA/… with Wildfly 9.x.

So here, I will not discuss pros/cons neither compare it with PHP Symphony,  Python Django, or even Ruby on Rails; just give couple of Tips/Tricks around “Getting Started”

  1. Install : PostgreSQL & Wildfly
    – For my PoC/testing (Wildfly+Postgresql) server, I use a VPS (see OVH VPS for example: 1 Go RAM, 128Mo SWAP, 10Go HD)
    – Install Java on your server
    – Install PostgreSQL (9.4 or above) and starts it
    – Download Wildfly, uncompress, and runs it (here in standalone mode, listening all interfaces).

    bin/standalone.sh -b=0.0.0.0

  2. Configure WildFly DataSource
    This is a critical path: configure WildFly datasources. By default, an “ExampleDS”, using H2 memory database, is configured.
    Have a look over here (quick tutorial).
    There are plenty of ways to configured a PostgreSQL datasource using WildFly Web Administration, command-line client or simply “standalone.xml” edit.
  3. Setup a maven project
    In fact, this is where I’ve spent a lot of times: get a predefined maven project, from which I could start my tests/devs.
    Here is my pom.xml

  4. 1st tip : a generic “Reporitory” class
    As I did in a previous post regarding Symfony and a kind of “super” controller, I quickly had the same approach with Persistence/EJB. I created a top repository class to quickly handle simple stuff with @Entity.
    Here is my (old) very first but efficient AARootRepo.java
  5. 2nd tip/reminder: Hibernate key events/annotations
    Type Description
    @PrePersist Executed before the entity manager persist operation is actually executed or cascaded. This call is synchronous with the persist operation.
    @PreRemove Executed before the entity manager remove operation is actually executed or cascaded. This call is synchronous with the remove operation.
    @PostPersist Executed after the entity manager persist operation is actually executed or cascaded. This call is invoked after the database INSERT is executed.
    @PostRemove Executed after the entity manager remove operation is actually executed or cascaded. This call is synchronous with the remove operation.
    @PreUpdate Executed before the database UPDATE operation.
    @PostUpdate Executed after the database UPDATE operation.
    @PostLoad Executed after an entity has been loaded into the current persistence context or an entity has been refreshed.

    These events are quite useful to handle “json” data embedded into a blob/text field (through PostLoad/PreUpdate/PrePersist) for example, or to automatically update a field on persist/update (PrePersist/PreUpdate).

 

WildFly/JBoss / PostgreSQL : Draft

AlexBLeave a comment

First steps of tutorial (synthesis of readings).

  1. Download/Uncompress Wildfly
  2. Download/Install PostgreSQL (9.4 here)
  3. Configure PostgreSQL
    • Setup postgres password: 
      su - postgres
psql -c "ALTER USER postgres WITH PASSWORD 'postgres'" -d template1
exit
    • Allow authentification using md5 from local sockets 
      nano /etc/postgresql/9.4/main/pg_hba.conf
      # BEFORE: local   all          all           peer
local   all      all                     md5
# IPv4 local connections:
host    all      all        127.0.0.1/32       md5
# IPv6 local connections:
host    all        all       ::1/128           md5

      then restart PostgreSQL service

    • Create database…
  4. To start in standalone mode listening on all IP addresses : bin/standalone.sh -b0.0.0.0
  5. Download PostgreSQL JDBC Driver (Here for Java 1.7+) JDBC Driver (PostgreSQL 9.4) into /tmp
  6. Configure Wildfly (JDBC Driver && DataSource)
      • Start jboss-cli 
        bin/jboss-cli.sh
      • Install module: 
        module add --name=org.postgres --resources=/tmp/postgresql-9.4-1205.jdbc41.jar --dependencies=javax.api,javax.transaction.api
      • Declare JDBC Driver into Application Server 
        /subsystem=datasources/jdbc-driver=postgres:add(driver-name="postgres",driver-module-name="org.postgres",driver-class-name=org.postgresql.Driver)
      • Install datasource named “PostGreDS” 
        data-source add --jndi-name=java:/PostGreDS --name=PostgrePool --connection-url=jdbc:postgresql://localhost/postgres --driver-name=postgres --user-name=postgres
  7. Other stuffs 
    

    8. 



References: