Import Real-Time HDFS Data in ColdFusion to Build Applications

Adobe ColdFusion is a web and mobile application development platform. It uses its own scripting language, ColdFusion Markup Language (CFML), to create data-driven websites as well as generate remote services, such as REST.

When ColdFusion is paired with the CData JDBC Driver for HDFS, you can link your ColdFusion web and mobile applications to operational HDFS data. This allows for your applications to be more robust and complete. This article details how to use the JDBC driver to create a table populated with HDFS data from within a ColdFusion markup file.

With built-in optimized data processing, the CData JDBC Driver offers unmatched performance for interacting with live HDFS data. When you issue complex SQL queries to HDFS, the driver pushes supported SQL operations, like filters and aggregations, directly to HDFS and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations). Its built-in dynamic metadata querying allows you to work with and analyze HDFS data using native data types.

Configuring the Connection to HDFS

You will need a JDBC connection string to establish a connection between Coldfusion and HDFS.

In order to authenticate, set the following connection properties:

• Host: Set this value to the host of your HDFS installation.
• Port: Set this value to the port of your HDFS installation. Default port: 50070

Built-in Connection String Designer

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

Adding a Data Source and Creating a Table

After configuring the connection, follow the steps below to add the CData JDBC Driver to ColdFusion's lib directory, add a new data source, test the connection, create a ColdFusion markup file, and, finally, make a real-time connection with HDFS data and display it in a table written in the ColdFusion Markup Language, or CFML:

1. Copy the JDBC Driver for HDFS and lic file from "C:\Program Files\CData[product_name]\lib" to "C:\ColdFusion2021\cfusion\wwwroot\WEB-INF\lib". cdata.jdbc.hdfs.jar cdata.jdbc.hdfs.lic

   Note: If you do not copy the .lic file with the jar, you will see a licensing error that indicates you do not have a valid license installed. This is true for both the trial and full versions.

2. From the ColdFusion administrator interface, choose Data & Services.
3. Here, we can "Add New Data Source". The data source name can be any name, provided it conforms to the ColdFusion variable naming conventions. For our JDBC driver, choose "other", then click the "Add" button.
4. Next, populate the driver properties.
   • JDBC URL will need to be in the format: jdbc:hdfs:|connectionString|.
   • A typical connection string looks like this:

     jdbc:hdfs:Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;User=root;

   • The Driver Class is: cdata.jdbc.hdfs.HDFSDriver
   • The Driver Name is arbitrary and simply used to recognize the data source in the ColdFusion administration console.
5. Now, test the connection by clicking the check mark to the left of the CDataHDFSJDBC data source you just created. When the data source reports an "OK" status, it is ready for use.
6. Next, create a new ColdFusion Markup file (.cfm) and place it in the wwwroot directory ("C:\ColdFusion2021\cfusion\wwwroot") for ColdFusion.

   The following code queries the data source:

               
           <cfquery name="HDFSQuery" dataSource="CDataHDFSJDBC"> 
             SELECT * FROM Files 
           </cfquery> 
       

   And a CFTable can be used to quickly output the table in HTML:

               
             <cftable  
             query = "HDFSQuery" 
             border = "1" 
             colHeaders 
             colSpacing = "2" 
             headerLines = "2" 
             HTMLTable 
             maxRows = "500" 
             startRow = "1"> 
   
             <cfcol header="<b>FileId</b>" align="Left" width=2 text="FileId"/> 
   
             <cfcol header="<b>ChildrenNum</b>" align="Left" width=15 text="ChildrenNum"/> 
   
             ...
   
           </cftable> 
       

   Full code, including the HTML portion is available below:

               
           <html> 
           <head><title>CData Software | HDFS Files Table Demo </title></head> 
           <body> 
           <cfoutput>#ucase("HDFS Files Table Demo")#</cfoutput> 
           <cfquery name="HDFSQuery" dataSource="CDataHDFSJDBC"> 
   
             SELECT * FROM Files 
   
           </cfquery> 
           <cftable  
             query = "HDFSQuery" 
             border = "1" 
             colHeaders 
             colSpacing = "2" 
             headerLines = "2" 
             HTMLTable 
             maxRows = "500" 
             startRow = "1"> 
             <cfcol header="<b>FileId</b>" align="Left" width=2 text="FileId"/> 
   
             <cfcol header="<b>ChildrenNum</b>" align="Left" width=15 text="ChildrenNum"/> 
   
             ...
   
           </cftable> 
           </body> 
   
           </html>  
       

7. Finally, run the code locally in a browser at the default port of 8500. It produces a table populated with HDFS data!

As a note, the CData JDBC Drivers also support parameterized queries using the cfqueryparam element. For example: SELECT * FROM Account WHERE name =

Get Started Today

Download a free, 30-day trial of the CData JDBC Driver for HDFS and start building HDFS-connected applications with Adobe ColdFusion. Reach out to our Support Team if you have any questions.