Is it possible to open a database connection at runtime using quarkus jdbc drivers? If so how would I go about doing it. Also would the mechanism work with native images?
Basically I wish to get a connection object to the database so I can run a custom query.
You can override some properties at runtime. You can view them here:
quarkus datasources
runtime sounds confusing. You can override BEFORE starting app. Imagine the case, you have url_XXX and url_YYY.
You can start app with
-Dquarkus.datasource.jdbc.url=url_XXX
and get datasource with connection to url_XXX. There is no option to get connection to url_YYY in runtime. You'll have to restart app with
-Dquarkus.datasource.jdbc.url=url_YYY
in order to connect to different DB.
Another option would be to use named datasources, but still you have define them at build time and provide url BEFORE starting app.
-Dquarkus.datasource.YYY.jdbc.url=url_YYY -Dquarkus.datasource.XXX.jdbc.url=url_XXX
Quarkus names it "runtime", but actually it's "pre-runtime"
Related
Was wondering, what steps am I missing to get a jdbc embeded h2 database working in my play application? Following these docs.
So far editted Application.conf file to contain this:
db.default.driver=org.h2.Driver
db.default.url="jdbc:h2:databases/test"
db.default.user=test
db.default.password="testtest"
Next I created a libs directory and added the jar file
h2-1.3.174.jar
Is this necessary or does the provided driver handle all types of h2 databases (embeded and server - I know it handles in memory)?
Now in the controler how can I access the database? Do I have to start/shutdown the database?
I know I can get connections from the getConnection() method in play.db. But everytime I execute a statement through this connection I get an exception saying no data is available. If I then check - looks like directory
databases/test
was not created so no database files exist.
What am I missing?
H2 works out of the box. Just create a new project in the terminal.
Otherwise, to your listing:
I think you should change db.default.url="jdbc:h2:databases/test" to db.default.url="jdbc:h2:mem:play"
don't need to create lib directories. It's all handeled by the build in dependency mgmt sbt
Just use the model objects and call save/update. No need to call start/shutdown
you are in a framework, it's all there ready for you...
I think you should start reading the documentation from the beginning to the end and examine the example applications. It's all there what you are looking for.
In addition to myborobudur's answer I'll only mention, that you don't need to use memory database, as you can for an instance use file storage (Embedded) or even run H2 as a server and then connect to it with TCP in Server Mode... Everything is clearly described in H2 documentation.
I have a JAVA webapp which is using DB connection pooling for Tomcat+MySQL config.
I have another JAVA webapp which i want to deploy in the same Tomcat and connect to same MySQL database (even access the data from same tables).
I havent figured out a way how to achieve the same.
Should I have connection pooling context.xml for each of the webapps?
Or should I have a global configuration.
In the first case , I assume there is nothing different that i need to do. Only to deploy the webapp which has its own context.xml.. Please correct me if i'm wrong.
If having a global config is a better solution, how to achieve that. Haven't found any good tutorials about it. What changes in each of webapps need to made , so that it knows that it needs to read the global config.
There's nothing wrong with having a separate context for each webapp unless you want to centrally manage changes to the database (i.e. migrate it to a different DB, change connection parameters). If you think your connection properties will change or you want that flexibility then you can use a JNDI datasource in tomcat and manage it there (google is your friend for that).
I created a JDBC application using mysql5.5.14 .
I want to run it on other systems without mysql5.5.14.(but having java)
Is thee any way i can install(and configure) mysql5.5.14 on other systems via my application.
I'm not entirely sure what you're trying to do, but if you mean "configure" as in "create the same database tables and views", you can use something like Liquibase.
If you want to keep using JDBC but with another database system at the backend, you can just pass the JDBC driver's class name to the program through a configuration file and load the driver using
Class.forName(jdbcDriver)
when you start up your application.
HTH
Raku
I have some code that I want to make public. The code sends email via servers, connects to databases, and other tasks requiring usernames/passwords.
I'd like to store the passwords and such in a seperate configuration file so that I don't have to sanitize my code on every commit.
How can I do this? It would be easy to do in C using #define, but I'm not sure how to accomplish this in Java.
EDIT: The environment I'm using is Glassfish
The basic method is put the information in a properties file and use the Properties class to load it at run time. If you're using a J2EE server, database connections are configured in the server and the code references them by an abstract name.
I think I should add that if you're using a server, how to configure it and how to get the connections to your code will vary by server and J2EE level so post your environment. Using the Properties class is pretty obvious just by looking at the javadoc and the load() methods.
In glassfish, go to the admin console and under Resources create a new connection pool. That defines your database connection and will share a pool of those connections among your applications. Now under JDBC Resources, create a new entry that maps that pool to a name. The name is usually something like jdbc/myappname.
For a J2EE5 or later application, you can now add this as a class level variable:
#Resource(mappedName="jdbc/myappname") DataSource myDS;
At runtime the server will inject that resource to your database pool. Then when you need a connection, you can do this inside any method:
Connection conn = myDS.getConnection();
The result is your code doesn't have to care at all about the database connection information or managing a pool of connections. You can deploy the identical code on development and production servers, and they will get an appropriate connection. In order to get the injection, it has to be a class the server creates like an EJB, servlet, tag library handler, or JSF managed bean.
First question from me on stack overflow.
I have created a java web application containing a web service using netbeans (I hope a web application were the correct choice). I use the web application as is with no extra frameworks. This web service use a sqlite JDBC driver for accessing a sqlite database file.
My problem is that the file path end up incorrect when I try to form the JDBC connection string. Also, the working directory is different when deploying and when running JUnit tests. I read somewhere about including the file as a resource, but examples of this were nowhere to be seen.
In any case, what is the best way to open the sqlite database, both when the web service is deployed and when I test it "locally"?
I don't know much about web services, I just need it to work, so please, help me with the technicalities.
Update
To put this a litle bit in context, some "println" code gives this:
Printing the work directory from a simple JUnit test gives
C:\MinaFiler\Work\SOA\BusTimetableWS
Invoking a similar web servic method returns
C:\Program Files\sges-v3\glassfish\domains\domain1
The connection string is formed from prepending "jdbc:sqlite:" to the path which at the moment is absolute:
C:\MinaFiler\Work\SOA\BusTimetableWS\src\java\miun\bustimetable\database\sqlit\BusTimetableWS.db
However, this fails because my tests throws exceptions stating database tables doesn't exist although they really do, I can see them with sqlite3.exe .
One way would be to use a config file that you can read and fetch your connection string from there.
I'm sure the framework you are using has some kind of standard way of saving configurations.
Another option would be to place the db in a known relative path from your main execution files. Then when executed fetch your current directory, and look for the db from that path.
In any case, what is the best way to open the sqlite database, both when the web service is deployed and when I test it "locally"?
The web service should use a DataSource to retrieve a connection from a connection pool configured at the application server level. In your unit test, use whatever you want (a standalone connection pool, a direct JDBC connection).
But in both cases, why don't you use an absolute path to the database file in your jdbc url? From How to Specify Database Files:
jdbc:sqlite:C:/work/mydatabase.db
The working directory wouldn't matter if you do so.