Create a Data Access Object for CSV Data using JDBI

JDBI is a SQL convenience library for Java that exposes two different style APIs, a fluent style and a SQL object style. The CData JDBC Driver for CSV integrates connectivity to live CSV data in Java applications. By pairing these technologies, you gain simple, programmatic access to CSV data. This article explains how to build a basic Data Access Object (DAO) and the accompanying code to read CSV data.

Create a DAO for the CSV Customer Entity

The interface below declares the desired behavior for the SQL object to create a single method for each SQL statement to be implemented.

public interface MyCustomerDAO {
 //request specific data from CSV (String type is used for simplicity)
 @SqlQuery("SELECT TotalDue FROM Customer WHERE FirstName = :firstName")
 String findTotalDueByFirstName(@Bind("firstName") String firstName);

 /*
 * close with no args is used to close the connection
 */
 void close();
}

Open a Connection to CSV

Collect the necessary connection properties and construct the appropriate JDBC URL for connecting to CSV.

Connecting to Local or Cloud-Stored (Box, Google Drive, Amazon S3, SharePoint) CSV Files

CData Drivers let you work with CSV files stored locally and stored in cloud storage services like Box, Amazon S3, Google Drive, or SharePoint, right where they are.

Setting connection properties for local files

Set the URI property to local folder path.

Setting connection properties for files stored in Amazon S3

To connect to CSV file(s) within Amazon S3, set the URI property to the URI of the Bucket and Folder where the intended CSV files exist. In addition, at least set these properties:

• AWSAccessKey: AWS Access Key (username)
• AWSSecretKey: AWS Secret Key

Setting connection properties for files stored in Box

To connect to CSV file(s) within Box, set the URI property to the URI of the folder that includes the intended CSV file(s). Use the OAuth authentication method to connect to Box.

Dropbox

To connect to CSV file(s) within Dropbox, set the URI proprerty to the URI of the folder that includes the intended CSV file(s). Use the OAuth authentication method to connect to Dropbox. Either User Account or Service Account can be used to authenticate.

SharePoint Online (SOAP)

To connect to CSV file(s) within SharePoint with SOAP Schema, set the URI proprerty to the URI of the document library that includes the intended CSV file. Set User, Password, and StorageBaseURL.

SharePoint Online REST

To connect to CSV file(s) within SharePoint with REST Schema, set the URI proprerty to the URI of the document library that includes the intended CSV file. StorageBaseURL is optional. If not set, the driver will use the root drive. OAuth is used to authenticate.

Google Drive

To connect to CSV file(s) within Google Drive, set the URI property to the URI of the folder that includes the intended CSV file(s). Use the OAuth authentication method to connect and set InitiateOAuth to GETANDREFRESH.

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the CSV JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.csv.jar

Fill in the connection properties and copy the connection string to the clipboard.

👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)

A connection string for CSV will typically look like the following:

jdbc:csv:URI=/PATH/TO/MyCSVFilesFolder;

Use the configured JDBC URL to obtain an instance of the DAO interface. The particular method shown below will open a handle bound to the instance, so the instance needs to be closed explicitly to release the handle and the bound JDBC connection.

DBI dbi = new DBI("jdbc:csv:URI=/PATH/TO/MyCSVFilesFolder;");
MyCustomerDAO dao = dbi.open(MyCustomerDAO.class);

//do stuff with the DAO

dao.close();

Read CSV Data

With the connection open to CSV, simply call the previously defined method to retrieve data from the Customer entity in CSV.

//disply the result of our 'find' method
String totalDue = dao.findTotalDueByFirstName("Bob");
System.out.println(totalDue);

Since the JDBI library is able to work with JDBC connections, you can easily produce a SQL Object API for CSV by integrating with the CData JDBC Driver for CSV. Download a free trial and work with live CSV data in custom Java applications today.