How to upload Excel using springboot to mysql database?

This is ExcelController.java Module

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.InputStreamResource;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

import com.bezkoder.spring.files.excel.helper.ExcelHelper;
import com.bezkoder.spring.files.excel.message.ResponseMessage;
import com.bezkoder.spring.files.excel.model.Tutorial;
import com.bezkoder.spring.files.excel.service.ExcelService;

@CrossOrigin("http://localhost:8080")
@Controller
@RequestMapping("/api/excel")
public class ExcelController {

  @Autowired
  ExcelService fileService;

  @PostMapping("/upload")
  public ResponseEntity<ResponseMessage> uploadFile(@RequestParam("file") MultipartFile file) {
    String message = "";

    if (ExcelHelper.hasExcelFormat(file)) {
      try {
        fileService.save(file);

        message = "Uploaded the file successfully: " + file.getOriginalFilename();
        return ResponseEntity.status(HttpStatus.OK).body(new ResponseMessage(message));
      } catch (Exception e) {
        message = "Could not upload the file: " + file.getOriginalFilename() + "!";
        return ResponseEntity.status(HttpStatus.EXPECTATION_FAILED).body(new ResponseMessage(message));
      }
    }

    message = "Please upload an excel file!";
    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(new ResponseMessage(message));
  }

  @GetMapping("/tutorials")
  public ResponseEntity<List<Tutorial>> getAllTutorials() {
    try {
      List<Tutorial> tutorials = fileService.getAllTutorials();

      if (tutorials.isEmpty()) {
        return new ResponseEntity<>(HttpStatus.NO_CONTENT);
      }

      return new ResponseEntity<>(tutorials, HttpStatus.OK);
    } catch (Exception e) {
      return new ResponseEntity<>(null, HttpStatus.INTERNAL_SERVER_ERROR);
    }
  }

  @GetMapping("/download")
  public ResponseEntity<Resource> getFile() {
    String filename = "tutorials.xlsx";
    InputStreamResource file = new InputStreamResource(fileService.load());

    return ResponseEntity.ok()
        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=" + filename)
        .contentType(MediaType.parseMediaType("application/vnd.ms-excel"))
        .body(file);
  }

}

This is FileUploadException.java Module

import org.springframework.web.multipart.MaxUploadSizeExceededException;
import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;

import com.bezkoder.spring.files.excel.message.ResponseMessage;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;

@ControllerAdvice
public class FileUploadExceptionAdvice extends ResponseEntityExceptionHandler {

  @ExceptionHandler(MaxUploadSizeExceededException.class)
  public ResponseEntity<ResponseMessage> handleMaxSizeException(MaxUploadSizeExceededException exc) {
    return ResponseEntity.status(HttpStatus.EXPECTATION_FAILED).body(new ResponseMessage("File too large!"));
  }
}

This is ExcelHelper.java Module

package com.bezkoder.spring.files.excel.helper;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.web.multipart.MultipartFile;

import com.bezkoder.spring.files.excel.model.Tutorial;

public class ExcelHelper {
  public static String TYPE = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
  static String[] HEADERs = { "Id", "Title", "Description", "Published" };
  static String SHEET = "Tutorials";

  public static boolean hasExcelFormat(MultipartFile file) {

    if (!TYPE.equals(file.getContentType())) {
      return false;
    }

    return true;
  }

  public static ByteArrayInputStream tutorialsToExcel(List<Tutorial> tutorials) {

    try (Workbook workbook = new XSSFWorkbook(); ByteArrayOutputStream out = new ByteArrayOutputStream();) {
      Sheet sheet = workbook.createSheet(SHEET);

      // Header
      Row headerRow = sheet.createRow(0);

      for (int col = 0; col < HEADERs.length; col++) {
        Cell cell = headerRow.createCell(col);
        cell.setCellValue(HEADERs[col]);
      }

      int rowIdx = 1;
      for (Tutorial tutorial : tutorials) {
        Row row = sheet.createRow(rowIdx++);

        row.createCell(0).setCellValue(tutorial.getId());
        row.createCell(1).setCellValue(tutorial.getTitle());
        row.createCell(2).setCellValue(tutorial.getDescription());
        row.createCell(3).setCellValue(tutorial.isPublished());
      }

      workbook.write(out);
      return new ByteArrayInputStream(out.toByteArray());
    } catch (IOException e) {
      throw new RuntimeException("fail to import data to Excel file: " + e.getMessage());
    }
  }

  public static List<Tutorial> excelToTutorials(InputStream is) {
    try {
//      Workbook workbook = new XSSFWorkbook(is);
//
//      Sheet sheet = workbook.getSheet(SHEET);
      Workbook workbook = WorkbookFactory.create(is);
      Sheet sheet = workbook.getSheetAt(0);

      Iterator<Row> rows = sheet.iterator();

      List<Tutorial> tutorials = new ArrayList<Tutorial>();

      int rowNumber = 0;
      while (rows.hasNext()) {
        Row currentRow = rows.next();

        // skip header
        if (rowNumber == 0) {
          rowNumber++;
          continue;
        }

        Iterator<Cell> cellsInRow = currentRow.iterator();

        Tutorial tutorial = new Tutorial();

        int cellIdx = 0;
        while (cellsInRow.hasNext()) {
          Cell currentCell = cellsInRow.next();

          switch (cellIdx) {
          case 0:
            tutorial.setId((long) currentCell.getNumericCellValue());
            break;

          case 1:
            tutorial.setTitle(currentCell.getStringCellValue());
            break;

          case 2:
            tutorial.setDescription(currentCell.getStringCellValue());
            break;

          case 3:
            tutorial.setPublished(currentCell.getBooleanCellValue());
            break;

          default:
            break;
          }

          cellIdx++;
        }

        tutorials.add(tutorial);
      }

      workbook.close();

      return tutorials;
    } catch (IOException e) {
      throw new RuntimeException("fail to parse Excel file: " + e.getMessage());
    }
  }
}

This is ResponseMessage.java Module

package com.bezkoder.spring.files.excel.message;

public class ResponseMessage {
  private String message;

  public ResponseMessage(String message) {
    this.message = message;
  }

  public String getMessage() {
    return message;
  }

  public void setMessage(String message) {
    this.message = message;
  }

}

This is tutorial.java Module

package com.bezkoder.spring.files.excel.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "tutorials")
public class Tutorial {

  @Id
  @Column(name = "id")
  private long id;

  @Column(name = "title")
  private String title;

  @Column(name = "description")
  private String description;

  @Column(name = "published")
  private boolean published;

  public Tutorial() {

  }

  public Tutorial(String title, String description, boolean published) {
    this.title = title;
    this.description = description;
    this.published = published;
  }

  public long getId() {
    return id;
  }

  public void setId(long id) {
    this.id = id;
  }

  public String getTitle() {
    return title;
  }

  public void setTitle(String title) {
    this.title = title;
  }

  public String getDescription() {
    return description;
  }

  public void setDescription(String description) {
    this.description = description;
  }

  public boolean isPublished() {
    return published;
  }

  public void setPublished(boolean isPublished) {
    this.published = isPublished;
  }

  @Override
  public String toString() {
    return "Tutorial [id=" + id + ", title=" + title + ", desc=" + description + ", published=" + published + "]";
  }

}

This is TutorialRespository.java Module

package com.bezkoder.spring.files.excel.repository;

import org.springframework.data.jpa.repository.JpaRepository;

import com.bezkoder.spring.files.excel.model.Tutorial;

public interface TutorialRepository extends JpaRepository<Tutorial, Long> {
}

This is my application.properties Module

spring.datasource.url= jdbc:mysql://localhost:3306/test?allowPublicKeyRetrieval=true&useSSL=false
spring.datasource.username= root
spring.datasource.password= 1234

spring.jpa.properties.hibernate.dialect= org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto= update

spring.servlet.multipart.max-file-size=2MB
spring.servlet.multipart.max-request-size=2MB

This is the Postman interface Postman Headers On enabling Content-Type as "multipart/form-data; boundary=" I get a blank response with no message. On enabling the Content-Type with "application/vnd.ms-excel" I get a 500 Internal Server Error, with the message: "Current request is not a multipart request". Postman Body

Thus, the uploading of excel using Postman is not working as desired. The download link is working fine, it downloads a blank excel sheet with just the column headings. Also, the table structure is being created in the MySQL database. How do I make the upload function work?