Create a Data Access Object for Exa 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 Exa integrates connectivity to live Exa data in Java applications. By pairing these technologies, you gain simple, programmatic access to Exa data. This article explains how to build a basic Data Access Object (DAO) and the accompanying code to read Exa data.

Create a DAO for the Exa Answer 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 MyAnswerDAO {
  //request specific data from Exa (String type is used for simplicity)
  @SqlQuery("SELECT Answer FROM Answer WHERE RequestId = :requestId")
  String findAnswerByRequestId(@Bind("requestId") String requestId);

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

Open a Connection to Exa

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

Start by setting the Profile connection property to the location of the Exa Profile on disk (e.g. C:\profiles\Exa.apip). Next, set the ProfileSettings connection property to the connection string for Exa (see below).

Exa API Profile Settings

Visit dashboard.exa.ai, sign in or create an account, and generate an API key from your API settings.

Built-in Connection String Designer

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

java -jar cdata.jdbc.api.jar

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

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

jdbc:api:Profile=C:\profiles\Exa.apip;ProfileSettings='APIKey=your_api_key';

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:api:Profile=C:\profiles\Exa.apip;ProfileSettings='APIKey=your_api_key';");
MyAnswerDAO dao = dbi.open(MyAnswerDAO.class);

//do stuff with the DAO

dao.close();

Read Exa Data

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

//disply the result of our 'find' method
String answer = dao.findAnswerByRequestId("my-request-id");
System.out.println(answer);

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