How to create link that downloads a PDF that is in byte array form

I have a byte array of a PDF from a database call I made and now I want to make it so that the user can click a link and download the PDF of that byte array. This is what I have attempted.

<a href="<s:url action='downloadPdf'/>">Download PDF</a>

public class DownloadPdf extends ActionSupport {
    private InputStream inputStream;
    private String fileName;

    public InputStream getInputStream() {
        return inputStream;
    }

    public String getFileName() {
        return fileName;
    }

    public String execute() {
        try {
            apiClass.connect();
            byte[] pdfBytes = apiClass.getByteArray(1);
            apiClass.close();
            
            if (pdfBytes != null && pdfBytes.length > 0) {
                inputStream = new ByteArrayInputStream(pdfBytes);
                fileName = "download.pdf"; 
                return SUCCESS; // Return SUCCESS to trigger the stream download
            } else {
                addActionError("PDF data not found.");
                return ERROR; 
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
            addActionError("Error retrieving PDF: " + e.getMessage());
            return ERROR;
        }
    }
}

<package name="default" extends="struts-default">
    <action name="downloadPdf" class="testingPurposes.testing.example.DownloadPdf">
        <result name="success" type="stream">
            <param name="contentType">application/pdf</param>
            <param name="contentDisposition">attachment;filename=${fileName}</param>
            <param name="inputName">inputStream</param>
        </result>
    </action>
</package>

However, I always get this error:

Messages:   
Can not find a java.io.InputStream with the name [inputStream] in the invocation stack. Check the <param name="inputName"> tag specified for this action is correct, not excluded and accepted.
File:   org/apache/struts2/result/StreamResult.java
Line number:    228

I was expecting the PDF to automatically begin downloading after you click the link. This is a solution I was suggested by ChatGPT since I cannot find anything on the internet.

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