File转换为MultipartFile工具类

package cn.com.utils;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.springframework.util.FileCopyUtils;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

import javax.activation.MimetypesFileTypeMap;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;

public class FileToMultipartFileUtil {


    public static MultipartFile toMultipartFile(String fieldName, File file) throws Exception {
        DiskFileItemFactory diskFileItemFactory = new DiskFileItemFactory();
        String contentType = new MimetypesFileTypeMap().getContentType(file);
        FileItem fileItem = diskFileItemFactory.createItem(fieldName, contentType, false, file.getName());
        try (
                InputStream inputStream = new ByteArrayInputStream(FileCopyUtils.copyToByteArray(file));
                OutputStream outputStream = fileItem.getOutputStream()
        ) {
            FileCopyUtils.copy(inputStream, outputStream);
        } catch (Exception e) {
            throw e;
        }
        MultipartFile multipartFile = new CommonsMultipartFile(fileItem);
        return multipartFile;
    }


    public static MultipartFile toMultipartFile(String fieldName, String fileName, byte[] fileByteArray) throws Exception {
        DiskFileItemFactory diskFileItemFactory = new DiskFileItemFactory();
        String contentType = new MimetypesFileTypeMap().getContentType(fileName);
        FileItem fileItem = diskFileItemFactory.createItem(fieldName, contentType, false, fileName);
        try (
                InputStream inputStream = new ByteArrayInputStream(fileByteArray);
                OutputStream outputStream = fileItem.getOutputStream()
        ) {
            FileCopyUtils.copy(inputStream, outputStream);
        } catch (Exception e) {
            throw e;
        }
        MultipartFile multipartFile = new CommonsMultipartFile(fileItem);
        return multipartFile;
    }

}