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

Create a DAO for the Excel Sheet 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 MySheetDAO {
 //insert new data into Excel
 @SqlUpdate("INSERT INTO Sheet (Name, Revenue) values (:name, :revenue)")
 void insert(@Bind("name") String name, @Bind("revenue") String revenue);

 //request specific data from Excel (String type is used for simplicity)
 @SqlQuery("SELECT Revenue FROM Sheet WHERE Name = :name")
 String findRevenueByName(@Bind("name") String name);

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

Open a Connection to Excel

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

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

CData Drivers let you work with Excel 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 Excel file(s) within Amazon S3, set the URI property to the URI of the Bucket and Folder where the intended Excel 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 Excel file(s) within Box, set the URI property to the URI of the folder that includes the intended Excel file(s). Use the OAuth authentication method to connect to Box.

Dropbox

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

SharePoint Online REST

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

Google Drive

To connect to Excel file(s) within Google Drive, set the URI property to the URI of the folder that includes the intended Excel 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 Excel JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.excel.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 Excel will typically look like the following:

jdbc:excel:URI='C:/MyExcelWorkbooks/SampleWorkbook.xlsx';

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:excel:URI='C:/MyExcelWorkbooks/SampleWorkbook.xlsx';");
MySheetDAO dao = dbi.open(MySheetDAO.class);

//do stuff with the DAO

dao.close();

Read Excel Data

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

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

Write Excel Data

It is also simple to write data to Excel, using the previously defined method.

//add a new entry to the Sheet entity
dao.insert(newName, newRevenue);

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