How to Convert CSV to an Excel XLSX Spreadsheet using Java

Since CSV is one of the most popular destination formats for Excel files, it’s imperative that we have a way to easily convert CSV back to Excel. With our CSV to XLSX conversion API, you can incorporate this common conversion into your application for free — you just need to register a free account on our website and use the code examples below to structure your API call in Java (you can also find comparable code in 10+ additional programming languages on our API console page).

To begin, let’s install the API client with Maven. Add a reference to the repository in pom.xml:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

Then add a reference to the pom.xml dependency:

<dependencies>
<dependency>
    <groupId>com.github.Cloudmersive</groupId>
    <artifactId>Cloudmersive.APIClient.Java</artifactId>
    <version>v4.25</version>
</dependency>
</dependencies>

With installation complete, include the imports at the top of the file, and then call the function:

// Import classes:
//import com.cloudmersive.client.invoker.ApiClient;
//import com.cloudmersive.client.invoker.ApiException;
//import com.cloudmersive.client.invoker.Configuration;
//import com.cloudmersive.client.invoker.auth.*;
//import com.cloudmersive.client.ConvertDocumentApi;
ApiClient defaultClient = Configuration.getDefaultApiClient();
// Configure API key authorization: Apikey
ApiKeyAuth Apikey = (ApiKeyAuth) defaultClient.getAuthentication("Apikey");
Apikey.setApiKey("YOUR API KEY");
// Uncomment the following line to set a prefix for the API key, e.g. "Token" (defaults to null)
//Apikey.setApiKeyPrefix("Token");
ConvertDocumentApi apiInstance = new ConvertDocumentApi();
File inputFile = new File("/path/to/inputfile"); // File | Input file to perform the operation on.
try {
    byte[] result = apiInstance.convertDocumentCsvToXlsx(inputFile);
    System.out.println(result);
} catch (ApiException e) {
    System.err.println("Exception when calling ConvertDocumentApi#convertDocumentCsvToXlsx");
    e.printStackTrace();
}

Include your API key and input file path in the appropriate fields, and you’re all done. Simple as can be!