Dynamic QR-Code Labels with Java and Spring Boot

• This is the entry point for the Spring Boot application. The @SpringBootApplication annotation marks it as the main class.

7. Create the QR Code Controller Class

• Insert the following code below the Main Application Class:

@RestController
@RequestMapping("/api/labels")
class QRCodeLabelController{

	@PostMapping(value= "/generate", produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
	public ResponseEntity<InputStreamResource> generateLabels(@RequestBody List<String> productIDs){
		try{
			XWPFDocument document = new XWPFDocument();
			try{
				XWPFTable table = document.createTable();
				table.removeRow(0);
				int columnsPerRow = 2;
				int currentColumn = 0;
				XWPFTableRow row = null;

				for (String productID : productIDs){
					if(productID != null & !productID.isEmpty()){

						String qrImageFile = productID + "-qr.jpeg";
						QRCode qr = new QRCode();
						qr.setDataToEncode(productID);
						new barCodeEncoder(qr,"JPEG", qrImageFile);

						if(currentColumn ==0){
							row =table.createRow();
						}

						XWPFTableCell cell = row.getCell(currentColumn);

						if(cell==null){
							cell = row.addNewTableCell();
						}

						XWPFParagraph cellParagraph = cell.addParagraph();
						XWPFRun textRun = cellParagraph.createRun();
						textRun.setText("Label for: " + productID);
						textRun.addBreak();

						try (FileInputStream imageStream = new FileInputStream(qrImageFile)){
							XWPFRun imageRun = cellParagraph.createRun();
							imageRun.addPicture(
									imageStream,
									XWPFDocument.PICTURE_TYPE_JPEG,
									qrImageFile,
									Units.toEMU(70),
									Units.toEMU(70)
							);
						}
						currentColumn++;
						if(currentColumn >= columnsPerRow){
							currentColumn= 0;
						}
					}
				}
				ByteArrayOutputStream outStream = new ByteArrayOutputStream();
				document.write(outStream);

				for(String productID : productIDs){
					new File(productID + "-qr.jpeg").delete();
				}

				ByteArrayInputStream inputStream = new ByteArrayInputStream(outStream.toByteArray());
				InputStreamResource resource = new InputStreamResource(inputStream);
				return ResponseEntity.ok()
						.header(HttpHeaders.CONTENT_DISPOSITION,"attachment; filename=LabelsWithQR.docx")
						.contentType(MediaType.APPLICATION_OCTET_STREAM)
						.body(resource);
			} catch(Exception e){
				e.printStackTrace();
				return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
			} finally{
				try{
					document.close();
				}catch(IOException e){
					e.printStackTrace();
				}
			}
		}
		catch(Exception e){
			throw new RuntimeException(e);
		}
	}

• @PostMapping("/generate"): Specifies that this method will handle POST requests made to /api/labels/generate
• @RequestBody List<String> productIDs: The method expects a list of product IDs in the body of the POST request.
• produces = MediaType.APPLICATION_OCTET_STREAM_VALUE: This tells the client that the response will be a binary stream (in this case, a Word document).
• XWPFDocument is part of the Apache POI library used for manipulating Word documents. A new document is created here.
• A table is created in the Word document. The first row is removed because it’s typically empty when a new table is created.
• The document will have two columns per row for the QR code labels.
• The loop iterates over the list of product IDs and checks if the ID is valid (not null or empty).
• A QR code is generated for each product ID and saved as a JPEG image file.
• If the current column is 0, a new row is created.
• For each product, a new table cell is created or reused, and a label is added with the product ID as text.
• The generated QR code image is read from the file system and inserted into the Word table cell.
• The image is resized to 70x70 units using Apache POI’s Units.toEMU method, which handles the conversion of pixel sizes to the required EMU (English Metric Units) format.
• After adding a label and its QR code to a cell, the current column counter is incremented.
• If the column exceeds the specified number (2 in this case), it resets to 0, moving to the next row.
• After all QR code labels are inserted, the document is written to an output stream (ByteArrayOutputStream).
• The temporary QR code image files are deleted from the file system.
• The Word document is returned as an attachment in the HTTP response, with the content type set to APPLICATION_OCTET_STREAM, allowing the client to download the file as LabelsWithQR.docx.
• If any error occurs, an HTTP 500 Internal Server Error is returned.
• The document is closed in a finally block to ensure resources are cleaned up.

8. Testing the API

• Run the application in IntelliJ
• Open Postman and set the request to POST
• Type in the URL: "http://localhost:8080/api/labels/generate"
• Add a header: Content-Type: application/json

• In the body, add the raw data for a JSON array of product IDs
• Example: ["Product-12345", "Product-67200", "Product-ABCDE","Product-234056","Product-867539","Product-199711"]
• Send the request

9. Download and Verify the Document

• Save the response
• Open the file in Word to see the QR Code labels

10. Adding the JAR as a Maven Dependency

Installing the JAR file locally ensures that Maven can access and use it during the build process, even if the JAR isn't available in a public Maven repository. This step is essential for incorporating custom or third-party libraries like the IDAutomation QR Code component into your project. Once installed, Maven treats the JAR as a local dependency, streamlining the development and deployment workflow.

• Install the JAR locally with the following command in the terminal from within the project directory:

mvn install:install-file
-Dfile="C:\Path\To\Jar\File\IDAQRCode.jar"
-DgroupId="com.idautomation" -DartifactId=IDAQRCode -Dversion=1
-Dpackaging=jar

• Reload Maven, refresh Maven to complete the dependency setup
• Test again!