How to upload and save image in MySQL via SpringBoot JPA - spring-boot

Question

I'm trying to upload and save an image in MySQL with SpringBoot using JPA but unfortunately I'm greeted with this error, can anyone tell me what am I missing ?
Error
Field error in object 'institution' on field 'logo': rejected value [org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile#387c2996]; codes [typeMismatch.institution.logo,typeMismatch.logo,typeMismatch.[Ljava.lang.Byte;,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [institution.logo,logo]; arguments []; default message [logo]]; default message [Failed to convert property value of type 'org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile' to required type 'java.lang.Byte[]' for property 'logo'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type 'org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile' to required type 'java.lang.Byte' for property 'logo[0]': PropertyEditor [org.springframework.beans.propertyeditors.CustomNumberEditor] returned inappropriate value of type 'org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile']]
pom.xml
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.4</version>
</dependency>
Entity
#Lob
private Byte[] logo;
controller
#PostMapping("/institutionAddNew")
public String addNewComp(#ModelAttribute("institution") Institution institution, Model model,
HttpSession session,
#RequestParam CommonsMultipartFile fileUpload) throws Exception {
Integer insId = (Integer) session.getAttribute("instId");
Byte[] byteObjects = new Byte[fileUpload.getBytes().length];
int i = 0;
for (byte b : fileUpload.getBytes()){
byteObjects[i++] = b;
}
institution.setLogo(byteObjects);
cs.addNewInstitution(institution);
model.addAttribute("institutionlist", cs.getAllInstitutions(insId));
return "redirect:/showAllInstitutions";
}
Form
<form:form action="/institutionAddNew" method="post" modelAttribute="institution" enctype="multipart/form-data">
<form:input path="instName" />
<input type="file" name="logo" />
<button type="submit" class="btn btn-primary">Submit</button>
</form:form>

Answer 1

The provided information is insufficient to properly diagnose the problem. You need to provide more information.
But I am guessing that, when the jsp file is sending data to your controller, it is sending the file as a MultiPartFile. But your application is trying to cast it to an byte array. That's why your are getting the exception. The problem does not lie withJPA, the exception should happen before the data enters the controller.
You can use an dto object to pass the data to your controller where the file is a Multipartfile object, then you can prepare the entity object with the dto object data. Here you can read the multipartfile and convert it to an byte array and then save it to your database.
Add another InstitutionParam class like
public class InstitutionParam {
private MultipartFile logo;
}
Keep your Institution class same. Your controller should look like
#PostMapping("/institutionAddNew")
public String addNewComp(#ModelAttribute("institution") InstitutionParam institution, Model model,
HttpSession session) throws Exception {
Integer insId = (Integer) session.getAttribute("instId");
MultipartFile fileUpload = institution.getLogo();
Byte[] byteObjects = new Byte[fileUpload.getBytes().length];
int i = 0;
for (byte b : fileUpload.getBytes()){
byteObjects[i++] = b;
}
Institution entity = new Institution();
entity.setLogo(byteObjects);
// save to db
cs.addNewInstitution(institution);
model.addAttribute("institutionlist", cs.getAllInstitutions(insId));
return "redirect:/showAllInstitutions";
}

Answer 2

I've managed to solve it eventually, I had to change the code. I'm sure there are many ways of doing this, not sure if this approached is the best one but it works for me.
Entity
private Integer instId;
private String fileName;
private String fileType;
#Lob
private byte[] image;
public Institution(Integer instId, String instName, String fileName, String fileType, byte[] image) {
super();
this.instId = instId;
this.instName = instName;
this.fileName = fileName;
this.fileType = fileType;
this.image = image;
}
Service
public Institution storeFile(Integer instId, String name, MultipartFile file) throws Exception {
String fileName = StringUtils.cleanPath(file.getOriginalFilename());
try {
Institution institution = new Institution(instId, name,fileName, file.getContentType(), file.getBytes());
return comrepos.save(institution);
} catch (IOException ex) {
throw new Exception("Could not store file " + fileName, e);
}
}
controller
#PostMapping("/institutionAddNew")
public String uploadImage(#RequestParam("image") MultipartFile file,
#RequestParam("instName") String name,
#RequestParam("instId") Integer instId) {
try {
iservice.storeFile(instId,name,file);
} catch (Exception e) {
e.printStackTrace();
}
return "redirect:/showAllInstitutions";
}
Form
<form:form action="/institutionAddNew" method="post" modelAttribute="institution" enctype="multipart/form-data">
<form:input path="instName" />
<input type="file" name="logo" />
<button type="submit" class="btn btn-primary">Submit</button>
</form:form>