How to create a custom REST API connector for Java
Learn how to quickly and efficiently connect Custom API with Java for smooth data access.
Read / write Custom API data without coding. You can do it all using the high-performance Custom API ODBC Driver for Java (often referred to as the Custom API Connector). How is this possible? You will connect to the ZappySys Data Gateway, which acts as a seamless bridge between the ODBC and JDBC layers. We'll walk you through the entire setup.
Ready to dive in? Download the product to jump right in, or follow the step-by-step guide below to see how it works.
Create Custom API Connector
First of all, you will have to create your own API connector.
For demonstration purposes, in this section we will create a simple Hello-World API connector that
calls ZappySys Sandbox World API endpoint https://sandbox.zappysys.com/api/world/hello.
When developing your Custom API Connector, just replace it with your real API method/endpoint.
Let's dive in and follow these steps:
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Search for
odbcand open the ODBC Data Sources (64-bit):
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Create a User data source (User DSN) based on the ZappySys JSON Driver driver:
ZappySys JSON Driver
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Once the data source configuration window opens, enter this URL into the text box:
https://sandbox.zappysys.com/api/world/hello
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Then go to the Preview tab and try to say "Hello!" to the World!
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Since the test is successful, you are ready to create the Hello-World Connector:
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The API Connector File Wizard opens, click Next:
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Leave the default option, and click Next again:
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Just click Next in the next window:
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Let's give our new custom connector a name it deserves:
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Then just click Next in the Connection Types window:
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Let's name the hello endpoint (it deserves a name too!):
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When the next window opens, delete the default table (we won't need it for now):
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Finally, specify a path, where you want to save the newly created API Connector:
Create data source in ZappySys Data Gateway
In this section we will create a data source for Custom API in the Data Gateway. Let's follow these steps to accomplish that:
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Download and install ODBC PowerPack (if you haven't already).
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Search for
gatewayin the Windows Start Menu and open ZappySys Data Gateway Configuration:
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Go to the Users tab and follow these steps to add a Data Gateway user:
- Click the Add button
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In the Login field enter a username, e.g.,
john - Then enter a Password
- Check the Is Administrator checkbox
- Click OK to save
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Now we are ready to add a data source:
- Click the Add button
- Give the Data source a name (have it handy for later)
- Then select Native - ZappySys API Driver
- Finally, click OK
CustomApiDSNZappySys API Driver
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When the Configuration window appears give your data source a name if you haven't done that already. Then set the path to your created Custom API Connector (in the example below, we use Hello-World Connector). Finally, click Continue >> to proceed:
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Now it's time to configure the Connection Manager. Select Authentication Type, e.g. Token Authentication. Then select API Base URL (in most cases, the default one is the right one). Check your Custom API reference for more information on how to authenticate.
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Once the data source connection has been configured, it's time to configure the SQL query. Select the Preview tab and then click Query Builder button to configure the SQL query:
ZappySys API Driver - Custom APIRead / write Custom API data without coding.CustomApiDSN
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Start by selecting the Table or Endpoint you are interested in and then configure the parameters. This will generate a query that we will use in Java to retrieve data from Custom API. Hit OK button to use this query in the next step.
SELECT * FROM Orders
Some parameters configured in this window will be passed to the Custom API, e.g. filtering parameters. It means that filtering will be done on the server side (instead of the client side), enabling you to get only the meaningful datamuch faster . -
Now hit Preview Data button to preview the data using the generated SQL query. If you are satisfied with the result, use this query in Java:
ZappySys API Driver - Custom APIRead / write Custom API data without coding.CustomApiDSNSELECT * FROM Orders
You can also access data quickly from the tables dropdown by selecting <Select table>.AWHEREclause,LIMITkeyword will be performed on the client side, meaning that thewhole result set will be retrieved from the Custom API first, and only then the filtering will be applied to the data. If possible, it is recommended to use parameters in Query Builder to filter the data on the server side (in Custom API servers). -
Click OK to finish creating the data source.
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Once done, go to the Network Settings tab and Add a firewall rule for inbound traffic:
- This will initially allow all inbound traffic.
- Click Edit IP filters to restrict access to specific IP addresses or ranges.
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Crucial Step: After creating or modifying the data source, you must:
- Click the Save button to persist your changes.
- Hit Yes when prompted to restart the Data Gateway service.
This ensures all changes are properly applied:
Skipping this step may cause the new settings to fail, preventing you from connecting to the data source.
Read data in Java from the DSN
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Java code to get the data:
"jdbc:sqlserver://localhost:5000;databasename=CustomApiDSN;user=john;password=test"
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When you run the code it will make the API call and read the data:
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Here is Java program's code in text format:
//Step-1: Install ZappySys ODBC PowerPack and Configure Data Gateway //Step-2:Assuming the Microsoft SQL Server JDBC Driver is in below folder //C:\Program Files\Microsoft Jdbc Driver 6.0 for SQL Server\sqljdbc_6.0\enu\auth\x64 package padaone; import java.sql.*; public class zappy { public static void main(String[] args) { // Create a variable for the connection string. String connectionUrl = "jdbc:sqlserver://localhost:5000;databasename=CustomApiDSN;user=test;password=test"; // Declare the JDBC objects. Connection con = null; Statement stmt = null; ResultSet rs = null; try { // Establish the connection. Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); con = DriverManager.getConnection(connectionUrl); // Create and execute an SQL statement that returns some data. String SQL = "SELECT Country , SUM(UnitPrice * Quantity) Total " + "FROM value " + "GROUP BY Country " + "WITH (SRC='https://services.odata.org/V3/Northwind/Northwind.svc/Invoices?$format=json')"; stmt = con.createStatement(); rs = stmt.executeQuery(SQL); // Iterate through the data in the result set and display it. while (rs.next()) { System.out.println(rs.getString(1) + " " + rs.getString(2)); } } // Handle any errors that may have occurred. catch (Exception e) { e.printStackTrace(); } finally { if (rs != null) try { rs.close(); } catch (Exception e) {} if (stmt != null) try { stmt.close(); } catch (Exception e) {} if (con != null) try { con.close(); } catch (Exception e) {} } } }
Conclusion
In this article we showed you how to connect to Custom API in Java and integrate data without writing complex code — all of this was powered by Custom API ODBC Driver.
Download ODBC PowerPack now or ping us via chat if you have any questions or are looking for a specific feature (you can also reach out to us by submitting a ticket):
