Upload Multiple Files in Spring Boot using JPA, Thymeleaf, Multipart

package com.example.user.modal;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Lob;
import javax.persistence.Table;

// Entity annotation defines that a 
// class can be mapped to a table
@Entity   

// @Table annotation defines name of the table
@Table(name = "filemodal") 
public class FileModal {
    // @Id annotation specifies the
    // primary key of an entity
    @Id  
  
    // @GeneratedValue annotation Provides for the 
    // specification of generation strategies
    // for the values of primary keys
    @GeneratedValue(strategy = GenerationType.IDENTITY) 
 
    // @Column annotation specifies
    // the name of the column
    @Column(name = "id") 
    long id;
    @Column(name = "name")
    String fileName;
    @Lob
    @Column(name = "content")
    String content;
    @Column(name = "filetype")
    private String fileType;

    public FileModal() {
        super();
    }
    public FileModal(String fileName, String content, String fileType) {
        super();
        this.fileName = fileName;
        this.content = content;
        this.fileType = fileType;
    }
    public String getFileName() {
        return fileName;
    }
    public void setFileName(String fileName) {
        this.fileName = fileName;
    }
    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }
    public String getFileType() {
        return fileType;
    }
    public void setFileType(String fileType) {
        this.fileType = fileType;
    }
}

package com.example.user.repoasitory;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import com.example.user.modal.FileModal;

// @Repository annotation is used to 
// indicate that the class provides the mechanism 
// for storage, retrieval, search,update and delete 
// operation on objects.
@Repository 
public interface FileRepository extends JpaRepository<FileModal, Long> {

}

package com.example.user.service;

import java.util.List;
import com.example.user.modal.FileModal;

public interface FileService {
    List<FileModal> getAllFiles();
    void saveAllFilesList(List<FileModal> fileList);
}

package com.example.user.service;

import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.example.user.modal.FileModal;
import com.example.user.repoasitory.FileRepository;

// @Service annotation is used with classes
// that provide some business functionalities
@Service 
public class FileServiceImplementation implements FileService {

    // @Autowired annotation used to inject 
    // the object dependency of FileRepository
    @Autowired  
    FileRepository fileRepository;
  
    @Override
    public List<FileModal> getAllFiles() {
        // fetch all the files form database
        return fileRepository.findAll();
    }
    public void saveAllFilesList(List<FileModal> fileList) {
        // Save all the files into database
        for (FileModal fileModal : fileList)
            fileRepository.save(fileModal);
    }
}

package com.example.user.controller;

import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;
import com.example.user.modal.FileModal;
import com.example.user.service.FileServiceImplementation;

// @Controller annotation is used to 
// mark any java class as a controller class
@Controller  
public class FileController {

    @Autowired 
    FileServiceImplementation fileServiceImplementation;

    // @GetMapping annotation for 
    // mapping HTTP GET requests onto
    // specific handler methods. */
    @GetMapping("/") 
    public String getData() {
        return "File";
    }
  
    // @PostMapping annotation maps HTTP POST 
    // requests onto specific handler methods
    @PostMapping("/") 
    public String uploadMultipartFile(@RequestParam("files") MultipartFile[] files, Model modal) {
    try {
        // Declare empty list for collect the files data 
        // which will come from UI
        List<FileModal> fileList = new ArrayList<FileModal>();
        for (MultipartFile file : files) {
            String fileContentType = file.getContentType();
            String sourceFileContent = new String(file.getBytes(), StandardCharsets.UTF_8);
            String fileName = file.getOriginalFilename();
            FileModal fileModal = new FileModal(fileName, sourceFileContent, fileContentType);
            
            // Adding file into fileList
            fileList.add(fileModal);
            }
      
            // Saving all the list item into database
            fileServiceImplementation.saveAllFilesList(fileList);

        } catch (Exception e) {
            e.printStackTrace();
        }
      
        // Send file list to View using modal class    
        // fileServiceImplementation.getAllFiles() used to 
        // fetch all file list from DB
        modal.addAttribute("allFiles", fileServiceImplementation.getAllFiles());
      
        return "FileList";
    }
}

package com.example.user;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

// Spring Boot @SpringBootApplication annotation is used to mark a configuration 
// class that declares one or more @Bean methods and also triggers auto-configuration
// and component scanning. It’s the same as declaring a class with @Configuration,
// @EnableAutoConfiguration and @ComponentScan annotations
@SpringBootApplication
public class FileApplication {

    public static void main(String[] args) {
        SpringApplication.run(FileApplication.class, args);
    }

}