i already setup oracle xadatasource in websphere, and i want get datasource by using spring context lookup jndi , exception happen when i start my app : WasjdbcDataSource incompatible with javax.sql.XADataSource.
how can i solve this?
In a Java EE application server, such as WebSphere Application Server, even though you configure the XA-capable javax.sql.XADataSource, the application (and Spring) should always expect to use it as javax.sql.DataSource. Look in the Spring configuration if there is a way to indicate the expected type of javax.sql.DataSource rather than javax.sql.XADataSource. The XADataSource API is intended only for the application server's own internal use in order to accomplish two-phase commit. The user always interacts with it as javax.sql.DataSource, and gains the ability to enlist multiple resources in a single global transaction.
Related
We had recently moved to building projects using Maven. Earlier, all the JARs were added in libs folder and added to classpath. While moving to the Maven build, I missed to add a dependency to the 'sqlite-jdbc'. This library is required to read data from a local .db3 file.
As the 'org.sqlite.JBDC' class was loaded by calling the code Class.forName("org.sqlite.JDBC"), there was no compilation error and I deployed the WAR file and servlet failed in the server. I was thinking of a way to find the issue at the compilation time itself to avoid any such mistakes in the future. Can I simply call the JDBC.PREFIX to load the JDBC, so that, If I forget to add the dependency to the pom.xml file, I can find the issue at the compile time, itself?
Is there was difference between Class.forName("org.sqlite.JDBC") vs JDBC.PREFIX to load JDBC class?
No need for Class.forName
There is no generally no need to call Class.forName.
Such calls were used in the early years. Modern Java was changed so that JDBC drivers are automatically loaded and registered with the JVM via the Java Service Provider Interface (SPI) facility.
If you are using books or tutorials advising Class.forName, you may want to obtain more up-to-date learning materials.
DataSource
Furthermore, in Servlet work you generally should not be explicitly accessing the JDBC driver.
Setting the database server address, username, and password would require hard-coding text. When the deployment sysadmins change the IP address, or rotate passwords, your code breaks. You would then have to modify your source code, re-compile, and re-deploy.
Instead, you should externalize such configuration details.
For SQLite, see Using DataSource to connect to SQLite with (Xerial) sqlite-jdbc driver.
JNDI
You can externalize database configuration by using the the DataSource interface. After obtaining a DataSource object at runtime, make database connections by calling its getConnection method. That DataSource object holds the database server address, username, password, and all other settings needed to make a connection to the database.
Obtain a DataSource object at runtime by using JNDI. Your Servlet container may act as the naming/directory server to provide the DataSource object, if your sysadmin so configures it. Or the DataSource can be obtained via JNDI from an external server such as an LDAP server.
Again, the beauty of using DataSource and JNDI is that you as the Servlet programmer need not be involved, or even informed, when the deployment details change.
JDBC driver location
For Servlet work, you generally do not bundle the JDBC driver with your app.
Instead, the JDBC driver goes into a folder managed by your Servlet container. Study the documentation for your particular Servlet container. For Apache Tomcat, see this Answer.
In development, your IDE may need access to the JDBC driver to compile. If so, in your Maven POM, mark the dependency with a <scope>provided</scope> element. This tag tells Maven to omit that dependency from the final build because the dependency will already be present (provided) at runtime.
If you insist on bundling your JDBC driver within the WAR file of your web app, then see the important Comment by Mark Rotteveel.
This topic has been addressed many times on Stack Overflow. Search to learn more.
I have a wildfly 10 (Java + Spring) project. I have a requirement to dynamically inject the datasource (mysql) config details to wildfly. But since wildfly depends on the standalone xml file at startup, and needs it before even the java beans are created, the only way I've found so far is to inject is by setting env vars (by running some other program/script to fetch the configs before wildfly starts). Is there any other better option?
Is it possible to do this through the same java application itself, ignoring the xml and set the right config? If yes, how?
DataSource object via JNDI
Externalize your JDBC connection details by using JNDI to access a naming/directory server to obtain an object implementing the DataSource interface.
With a DataSource object in hand, call getConnection to obtain a Connection.
See tutorial by Oracle, Connecting with DataSource Objects.
I'm writing a web application in Java and use Hibernate to map the database with my java objects. In Hibernate I connect to the database using C3PO pool. Now I need to schedule some tasks. Herefore I will use Quartz. Now the scheduled tasks will be stored in the database. It is possible to share the connection pool of C3PO with Quartz? So that the database settings are in one and the same file and that only one library is responsible to open a databaseconnection.
This is sort of a subjective thing, but suffice it to say, if you want to share the connection you have a number of options.
If you are using spring, define the c3p0 connection pool as a bean and inject it into both the Hibernate session factory and the Quartz scheduler beans.
If you are trying to stay "pure" and not using Spring, you can define your a JNDI based data-source at the container level.
There are some nuances with both approaches.
Unfortunately without indicating how "portable" you are trying to be and what you are currently using beyond just 'java', 'quartz-scheduler' and 'c3p0' as tags an answer will be vague at best.
EDIT
Thanks to the OP for adding additional information.
So with regard to that information, if you are using a Dynamic Web Project, you may be able to add a container specific deployment descriptor to WebContent directory.
For tomcat, META-INF/context.xml
For Jetty, WEB-INF/jetty-web.xml
With those, you can define a JNDI data source. Refer to the specific container for information on how to do that. Once done, Hibernate and Quartz can be configured to use a JNDI reference for the data source you have configured.
Is it possible to provide and lookup connection factories that are transactional on a JBoss AS 7? The standard "RemoteConnectionFactory" doesn't seem to be transactional (XA) and I don't know how to make it XA or how to define some sort of XARemoteConnectionFactory that I can use from a remote client.
I tried adding the <xa>true</xa> element (which works in a hornetq configuration but is illegal in a jboss config file) and tried to create a <pooled-connection-factory> like the "java:/jmsXA" (but I wasn't able to look it up in the context even with a correct name for exporting).
I have a Web application running on Oracle Weblogic Server 11g.
It uses a datasource defined in the application server to connect to the Oracle Database (11g too), its class is
oracle.jdbc.xa.client.OracleXADataSource
If for some reason the database becomes not present and then comes
backs, the application is running ok (it gets exceptions while trying
to access the db but this is fine and then can again get some new
connections when the db comes back)
However, if the database is down during weblogic server startup,
the datasource is not deployed on the server and the application
throws an exception because it has not any datasource available, the
deployment is marked as failed and of course nothing does repair this
automatically.
Is there a way to make the datasource be deployed even if the database is not present during server startup ? (such that the application becomes usable when the database is back)
Why do you want to deploy an application without a valid datasource?
You could possibly fake the datasource (create a dummy datasource with the same JNDI name) and assuming that the application does not validate datasource schema at startup you will get a semi-functional running application (which will fail with the first DB interaction).
When the real datasource is up and running you won't be able to switch to it. You will still have to restart the application server.
Update:
According to the J2EE spec (1.5 version) resources are binded during the deployment process. I believe that it is possible to implement a custom Factory that will return dummy / active datasource. Does it worth the effort to implement? ;)
EE.5.6.2 Deployer’s Responsibilities
Bind the resource manager connection factory reference to a resource manager connection factory that exists in the operational environment. The Deployer may use, for example, the JNDI LinkRef mechanism to create a symbolic link to the actual JNDI name of the resource manager connection factory. The re- source manager connection factory type must be compatible with the type de- clared in the res-type element.
The option you are looking for is "Connection Creation Retries", check this link
"If set and if the database is unavailable when the data source is created, WebLogic Server attempts to create connections in the pool again after the number of seconds you specify, and will continue to attempt to create the connections until it succeeds. This option applies to connections created when the data source is created at server startup ..."
set "Initial Capacity" http://docs.oracle.com/cd/E14571_01/web.1111/e13814/jdbc_tuning.htm#i1028616 to 0: weblogic on startup will not attempt to create any connection, and will not fail if the DB is not available.