imports

import java.io.FileNotFoundException; import java.io.IOException; import java.io.Writer; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.nio.file.StandardCopyOption; import java.util.List;

import com.itextpdf.io.source.ByteArrayOutputStream; import com.itextpdf.kernel.pdf.PdfWriter; import com.itextpdf.layout.Document; import com.itextpdf.layout.element.Paragraph; import com.itextpdf.layout.element.Table;

import org.apache.commons.csv.CSVFormat; import org.apache.commons.csv.CSVPrinter; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import org.springframework.util.StringUtils; import org.springframework.web.multipart.MultipartFile;

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CSV Controller @GetMapping("/export-to-csv") public void exportIntoCSV(HttpServletResponse response) throws IOException { response.setContentType("text/csv"); response.addHeader("Content-Disposition", "attachment; filename="student.csv""); fileStorageService.writeStudentsToCsv( response.getWriter()); }

 Service

@Override public void writeStudentsToCsv(Writer writer) throws IOException { try { writer.append("Id,studentName,email,mobileNo\n"); CSVPrinter printer = new CSVPrinter(writer, CSVFormat.DEFAULT);

		List<Student> students = this.repository.findAll();
		for (Student student : students) {
		printer.printRecord(student.getId(), student.getStudentName(), student.getEmail(),
		student.getMobileNo());
		
		}
		
		writer.flush();
		} catch (IOException e) {
		e.printStackTrace();
		}
	
}

---

pdf

controller @GetMapping("/export-pdf") public ResponseEntity<byte[]> exportToPdf() { ByteArrayOutputStream out = null; try { out = fileStorageService.exportDataToPdf(null); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }

        // Set headers for the PDF file download
        HttpHeaders headers = new HttpHeaders();
        headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=exported_data.pdf");
        headers.setContentType(MediaType.APPLICATION_PDF);

        return ResponseEntity
                .ok()
                .headers(headers)
                .body(out.toByteArray());
    }

 service
 @Override
public ByteArrayOutputStream exportDataToPdf(String filePath) throws FileNotFoundException {
	List<Student> students = this.repository.findAll();
	ByteArrayOutputStream out = new ByteArrayOutputStream();
    try {
    	// Initialize PDF writer
        PdfWriter writer = new PdfWriter(out);
        // Initialize PDF document
        com.itextpdf.kernel.pdf.PdfDocument pdfDoc = new com.itextpdf.kernel.pdf.PdfDocument(writer);
        // Initialize document
        Document document = new Document(pdfDoc);

        // Add a title
        document.add(new Paragraph("Exported Data").setBold().setFontSize(20));

        // Create a table with the same number of columns as your entity fields
        Table table = new Table(new float[]{2, 2, 2, 2}); // Adjust column widths as necessary
        table.addHeaderCell("ID");
        table.addHeaderCell("Student Name"); // Replace with your actual field names
        table.addHeaderCell("Email");
        table.addHeaderCell("Mobile No");

        // Add data rows
        for (Student entity : students) {
            table.addCell(entity.getId().toString());
            table.addCell(entity.getStudentName()); // Replace with your actual getter methods
            table.addCell(entity.getEmail());
            table.addCell(entity.getMobileNo());
        }

        // Add table to the document
        document.add(table);

        // Close document
        document.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
	
    return out;
}

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file upload Controller @PostMapping("/uploadFile") public ApiResponse<?> uploadFile(@RequestParam("file") MultipartFile file) { String fileName = null; try { fileName = fileStorageService.saveFile(file); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); }

        String fileDownloadUri = ServletUriComponentsBuilder.fromCurrentContextPath()
            .path("/downloadFile/")
            .path(fileName)
            .toUriString();

        return new ApiResponse<>(true, "SUCCESS", HttpStatus.OK.toString(), fileDownloadUri);
    }

 Service
 public FileUploadServiceImpl(FileStorageProperties fileStorageProperties) throws Exception {
	this.fileStorageLocation = Paths.get(fileStorageProperties.getUploadDir()).toAbsolutePath().normalize();

	try {
		Files.createDirectories(this.fileStorageLocation);
	} catch (Exception ex) {
		throw new Exception("Could not create the directory where the uploaded files will be stored.", ex);
	}
}