How to convert byte array to MultipartFile

org.springframework.web.multipart.MultipartFile is an interface so firstly you are going to need to work with an implementation of this interface.

The only implementation that I can see for that interface that you can use out-of-the-box is org.springframework.web.multipart.commons.CommonsMultipartFile. The API for that implementation can be found here

Alternatively as org.springframework.web.multipart.MultipartFile is an interface, you could provide your own implementation and simply wrap your byte array. As a trivial example:

/**<p>* Trivial implementation of the {@link MultipartFile} interface to wrap a byte[] decoded* from a BASE64 encoded String*</p>*/public class BASE64DecodedMultipartFile implements MultipartFile {        private final byte[] imgContent;        public BASE64DecodedMultipartFile(byte[] imgContent) {            this.imgContent = imgContent;        }        @Override        public String getName() {            // TODO - implementation depends on your requirements             return null;        }        @Override        public String getOriginalFilename() {            // TODO - implementation depends on your requirements            return null;        }        @Override        public String getContentType() {            // TODO - implementation depends on your requirements            return null;        }        @Override        public boolean isEmpty() {            return imgContent == null || imgContent.length == 0;        }        @Override        public long getSize() {            return imgContent.length;        }        @Override        public byte[] getBytes() throws IOException {            return imgContent;        }        @Override        public InputStream getInputStream() throws IOException {            return new ByteArrayInputStream(imgContent);        }        @Override        public void transferTo(File dest) throws IOException, IllegalStateException {             new FileOutputStream(dest).write(imgContent);        }    }

This answer has already been answered above. Recently i was working on the requirement to convert byte array object to multipartfile object. There are two ways to achieve this.

Approach 1:

Use the default CommonsMultipartFile where you to use the FileDiskItem object to create it.Example:

Approach 1:

Use the default CommonsMultipartFile where you to use the FileDiskItem object to create it.Example:

FileItem fileItem = new DiskFileItem("fileData", "application/pdf",true, outputFile.getName(), 100000000, new java.io.File(System.getProperty("java.io.tmpdir")));              MultipartFile multipartFile = new CommonsMultipartFile(fileItem);

Approach 2:

Create your own custom multipart file object and convert the byte array to multipartfile.

public class CustomMultipartFile implements MultipartFile {private final byte[] fileContent;private String fileName;private String contentType;private File file;private String destPath = System.getProperty("java.io.tmpdir");private FileOutputStream fileOutputStream;public CustomMultipartFile(byte[] fileData, String name) {    this.fileContent = fileData;    this.fileName = name;    file = new File(destPath + fileName);}@Overridepublic void transferTo(File dest) throws IOException, IllegalStateException {    fileOutputStream = new FileOutputStream(dest);    fileOutputStream.write(fileContent);}public void clearOutStreams() throws IOException {if (null != fileOutputStream) {        fileOutputStream.flush();        fileOutputStream.close();        file.deleteOnExit();    }}@Overridepublic byte[] getBytes() throws IOException {    return fileContent;}@Overridepublic InputStream getInputStream() throws IOException {    return new ByteArrayInputStream(fileContent);}}

This how you can use above CustomMultipartFile object.

String fileName = "intermediate.pdf";CustomMultipartFile customMultipartFile = new CustomMultipartFile(bytea, fileName);try {customMultipartFile.transferTo(customMultipartFile.getFile());} catch (IllegalStateException e) {    log.info("IllegalStateException : " + e);} catch (IOException e) {    log.info("IOException : " + e);}

This will create the required PDF and store that into

java.io.tmpdir with the name intermediate.pdf

Thanks.