How to get a DataSource?
connection, database, exception, java, jdbc
Solution
A `DataSource` allows getting a JDBC connection mostly from a pool of connections. A `DataSource` object represents a particular DBMS or some other data source, such as a file. If a company uses more than one data source, it will deploy a separate `DataSource` object for each of them. The `DataSource` interface is implemented by a driver vendor. You externalize DB connection properties file and fetch the object using JNDI. Using a `Datasource` you need to know only the JNDI name. The Application server cares about the details.
It can be implemented in three different ways:
- A basic `DataSource` implementation produces standard Connection objects that are not pooled or used in a distributed transaction.
- A `DataSource` implementation that supports connection pooling produces Connection objects that participate in connection pooling, that is, connections that can be recycled.
- A `DataSource` implementation that supports distributed transactions produces Connection objects that can be used in a distributed transaction, that is, a transaction that accesses two or more DBMS servers.
Like, in Spring, you can configure the datasource in an XML file and then (1) either inject it into your bean, (2) get it from `ApplicationContext`.
DataSource ds = (DataSource) ApplicationContextProvider.
getApplicationContext().getBean("myDataSource");
Connection c = ds.getConnection();
Suggested Reading:
- Connecting with DataSource Objects
- Why do we use a DataSource instead of a DriverManager?
- Data access with JDBC
- How to retrieve DB connection using DataSource without JNDI?
- Best way to manage DB connections without JNDI
Problem
I'm not certain how to get a `DataSource` object. I was able to use the `DriverManager` method to obtain a connection to a SQL database running on localhost, but every time I try to use the `DataSource` method to do so I wind up getting exceptions (mostly for naming). What I was wondering is: - Is it possible to get a `DataSource` object for local hosted databases? - Does the `DataSource` class need to be published, or is it like `DriverManager` where you just get a connection with no new class creation? - Could you show an example?