How to integrate Google Calendar using Java

Learn how to quickly and efficiently connect Google Calendar with Java for smooth data access.

Read and write Google Calendar data effortlessly. Integrate, manage, and automate events, calendars, and availability — almost no coding required. You can do it all using the high-performance Google Calendar ODBC Driver for Java (often referred to as the Google Calendar 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.

Google Calendar ODBC Driver Powering this integration

High performance
Bidirectional
Low-code / No-code
Easy to use

Built on the ZappySys API Driver, the Google Calendar ODBC Driver is a high-performance, low-code / no-code solution. It enables you to connect to Google Calendar data without any coding right in your SQL Server, or any ODBC/JDBC application. Part of the ODBC PowerPack.

Documentation

Create data source in ZappySys Data Gateway

In this section we will create a data source for Google Calendar in the Data Gateway. Let's follow these steps to accomplish that:

Download and install ODBC PowerPack (if you haven't already).
Search for gateway in the Windows Start Menu and open ZappySys Data Gateway Configuration:
Go to the Users tab and follow these steps to add a Data Gateway user:
- Click the Add button
- In the Login field enter a username, e.g., john
- Then enter a Password
- Check the Is Administrator checkbox
- Click OK to save
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
GoogleCalendarDSN

ZappySys API Driver
When the Configuration window appears give your data source a name if you haven't done that already, then select "Google Calendar" from the list of Popular Connectors. If "Google Calendar" is not present in the list, then click "Search Online" and download it. Then set the path to the location where you downloaded it. Finally, click Continue >> to proceed with configuring the DSN:

GoogleCalendarDSN

Google Calendar

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). More info is available in the Authentication section.

User Account

Google Calendar authentication

User accounts represent a developer, administrator, or any other person who interacts with Google APIs and services. User accounts are managed as Google Accounts, either with Google Workspace or Cloud Identity. They can also be user accounts that are managed by a third-party identity provider and federated with Workforce Identity Federation. [API reference]

Follow these steps on how to create Client Credentials (User Account principle) to authenticate and access Google Calendar API in SSIS package or ODBC data source:

WARNING: If you are planning to automate processes, we recommend that you use a Service Account authentication method. In case, you still need to use User Account, then make sure you use a system/generic account (e.g. automation@my-company.com). When you use a personal account which is tied to a specific employee profile and that employee leaves the company, the token may become invalid and any automated processes using that token will start to fail.

Step-1: Create project

This step is optional, if you already have a project in Google Cloud and can use it. However, if you don't, proceed with these simple steps to create one:

First of all, go to Google API Console.
Then click Select a project button and then click NEW PROJECT button:
Name your project and click CREATE button:
Wait until the project is created:
Done! Let's proceed to the next step.

Step-2: Enable Google Calendar API

In this step we will enable Google Calendar API:

Select your project on the top bar:
Then click the "hamburger" icon on the top left and access APIs & Services:
Now let's enable several APIs by clicking ENABLE APIS AND SERVICES button:
In the search bar search for calendar and then locate and select Google Calendar API:
Enable Google Calendar API:
Done! Let's proceed to the next step.

Step-3: Create OAuth application

First of all, click the "hamburger" icon on the top left and then hit VIEW ALL PRODUCTS:
Then access Google Auth Platform to start creating an OAuth application:
Start by pressing GET STARTED button:
Next, continue by filling in App name and User support email fields:
Choose Internal option, if it's enabled, otherwise select External:
Optional step if you used Internal option in the previous step. Nevertheless, if you had to use External option, then click ADD USERS to add a user:
Then add your contact Email address:
Finally, check the checkbox and click CREATE button:
Done! Let's create Client Credentials in the next step.

Step-4: Create Client Credentials

In Google Auth Platform, select Clients menu item and click CREATE CLIENT button:
Choose Desktop app as Application type and name your credentials:
Continue by opening the created credentials:
Finally, copy Client ID and Client secret for the later step:
Done! We have all the data needed for authentication, let's proceed to the last step!

Step-5: Configure connection

Now go to SSIS package or ODBC data source and use previously copied values in User Account authentication configuration:
- In the ClientId field paste the Client ID value.
- In the ClientSecret field paste the Client secret value.
Press Generate Token button to generate Access and Refresh Tokens.
Finally, click Test Connection to confirm the connection is working.
Done! Now you are ready to use Google Calendar Connector!

API Connection Manager configuration

Just perform these simple steps to finish authentication configuration:

Set Authentication Type to User Account [OAuth]
Optional step. Modify API Base URL if needed (in most cases default will work).
Fill in all the required parameters and set optional parameters if needed.
Press Generate Token button to generate the tokens.
Finally, hit OK button:

GoogleCalendarDSN

Google Calendar

User Account [OAuth]

https://www.googleapis.com/calendar/v3/

Required Parameters
UseCustomApp	Fill-in the parameter...
Optional Parameters
ClientId
ClientSecret
Scope	https://www.googleapis.com/auth/calendar
RetryMode	RetryWhenStatusCodeMatch
RetryStatusCodeList	403\|429
RetryCountMax	5
RetryMultiplyWaitTime	True
Redirect URL (Only for Web App)

Service Account (Using .json OR .p12 key file)

Google Calendar authentication

Service accounts are accounts that do not represent a human user. They provide a way to manage authentication and authorization when a human is not directly involved, such as when an application needs to access Google Cloud resources. Service accounts are managed by IAM. [API reference]

Follow these steps on how to create Service Account to authenticate and access Google Calendar API in SSIS package or ODBC data source:

Step-1: Create project

This step is optional, if you already have a project in Google Cloud and can use it. However, if you don't, proceed with these simple steps to create one:

First of all, go to Google API Console.
Then click Select a project button and then click NEW PROJECT button:
Name your project and click CREATE button:
Wait until the project is created:
Done! Let's proceed to the next step.

Step-2: Enable Google Calendar API

In this step we will enable Google Calendar API:

Select your project on the top bar:
Then click the "hamburger" icon on the top left and access APIs & Services:
Now let's enable several APIs by clicking ENABLE APIS AND SERVICES button:
In the search bar search for calendar and then locate and select Google Calendar API:
Enable Google Calendar API:
Done! Let's proceed to the next step.

Step-3: Create Service Account

Use the steps below to create a Service Account in Google Cloud:

First of all, go to IAM & Admin in Google Cloud console:
Once you do that, click Service Accounts on the left side and click CREATE SERVICE ACCOUNT button:
Then name your service account and click CREATE AND CONTINUE button:
Continue by clicking Select a role dropdown and start granting service account Project Viewer roles:
Find Project group and select Viewer role:
Finish adding roles by clicking CONTINUE button:

You can always add or modify permissions later in IAM & Admin.
Finally, in the last step, just click button DONE:
Done! We are ready to add a Key to this service account in the next step.

Step-4: Add Key to Service Account

We are ready to add a Key (P12 certificate) to the created Service Account:

In Service Accounts open newly created service account:
Next, copy email address of your service account for the later step:
Continue by selecting KEYS tab, then press ADD KEY dropdown, and click Create new key menu item:
Finally, select P12 option and hit CREATE button:
P12 certificate downloads into your machine. We have all the data needed for authentication, let's proceed to the last step!

Step-5: Share Google Calendar with Service Account

Now it's time to grant Google Calendar read/write permissions to the created service account:

Login to https://calendar.google.com with Google account credentials whose calendar you want to share with the service account.
On the top right click gear icon and click Settings item to open configuration.
Then on the left, click Settings of my calendars section.
Locate the calendar you want to share and select it.
In the dropdown hit Share with specific people or groups and click Add people and groups button.
Enter the service account email address we obtained in the previous section.
Finally, choose the permissions, e.g. Make changes to events:
Click Send button to share the calendar.
That's it! Let's proceed to the configuration!

Step-6: Configure connection

Now go to SSIS package or ODBC data source and configure these fields in Service Account authentication configuration:
- In the Service Account Email field paste the service account Email address value you copied in the previous step.
- In the Service Account Private Key Path (i.e. *.p12) field use downloaded certificate's file path.
Done! Now you are ready to use Google Calendar Connector!

API Connection Manager configuration

Just perform these simple steps to finish authentication configuration:

Set Authentication Type to Service Account (Using *.json OR *.p12 key file) [OAuth]
Optional step. Modify API Base URL if needed (in most cases default will work).
Fill in all the required parameters and set optional parameters if needed.
Finally, hit OK button:

GoogleCalendarDSN

Google Calendar

Service Account (Using *.json OR *.p12 key file) [OAuth]

https://www.googleapis.com/calendar/v3/

Required Parameters
Service Account Email	Fill-in the parameter...
Service Account Private Key Path (i.e. *.p12)	Fill-in the parameter...
Optional Parameters
Scope	https://www.googleapis.com/auth/calendar
RetryMode	RetryWhenStatusCodeMatch
RetryStatusCodeList	403\|429
RetryCountMax	5
RetryMultiplyWaitTime	True
Impersonate As (Enter Email Id)

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 - Google Calendar

Read and write Google Calendar data effortlessly. Integrate, manage, and automate events, calendars, and availability — almost no coding required.

GoogleCalendarDSN
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 Google Calendar. Hit OK button to use this query in the next step.
```
SELECT * FROM Calendars
-- Default: Lists calendars for the authenticated user

--OR--
--SELECT * FROM Calendars WITH(UserId='me') -- for OAuth authenticated user
--SELECT * FROM Calendars WITH(UserId='someuser@email.com') -- for specific user (requires domain-wide delegation for service accounts)
```
Some parameters configured in this window will be passed to the Google Calendar 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 data much 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 - Google Calendar

Read and write Google Calendar data effortlessly. Integrate, manage, and automate events, calendars, and availability — almost no coding required.

GoogleCalendarDSN
```
SELECT * FROM Calendars
-- Default: Lists calendars for the authenticated user

--OR--
--SELECT * FROM Calendars WITH(UserId='me') -- for OAuth authenticated user
--SELECT * FROM Calendars WITH(UserId='someuser@email.com') -- for specific user (requires domain-wide delegation for service accounts)
```
You can also access data quickly from the tables dropdown by selecting <Select table>.

A WHERE clause, LIMIT keyword will be performed on the client side, meaning that the whole result set will be retrieved from the Google Calendar 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 Google Calendar servers).
Click OK to finish creating the data source.
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.
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

Java code to get the data:

"jdbc:sqlserver://localhost:5000;databasename=GoogleCalendarDSN;user=john;password=test"
When you run the code it will make the API call and read the data:

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=GoogleCalendarDSN;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) {}
        }
    }
}

Supported Google Calendar Connector actions

Got a specific use case in mind? We've mapped out exactly how to perform a variety of essential Google Calendar operations directly in Java, so you don't have to figure out the setup from scratch. Check out the step-by-step guides below:

Conclusion

In this article we showed you how to connect to Google Calendar in Java and integrate data without writing complex code — all of this was powered by Google Calendar 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):

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