I am trying to upload a file with RestTemplate to Raspberry Pi with Jetty. On Pi there is a servlet running:
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
PrintWriter outp = resp.getWriter();
StringBuffer buff = new StringBuffer();
File file1 = (File) req.getAttribute("userfile1");
String p = req.getParameter("path");
boolean success = false;
if (file1 == null || !file1.exists()) {
buff.append("File does not exist\n");
} else if (file1.isDirectory()) {
buff.append("File is a directory\n");
} else {
File outputFile = new File(req.getParameter("userfile1"));
if(isValidPath(p)){
p = DRIVE_ROOT + p;
final File finalDest = new File(p
+ outputFile.getName());
success = false;
try {
copyFileUsingFileChannels(file1, finalDest);
finalDest.setWritable(true);
success = true;
} catch (Exception e) {
e.printStackTrace();
}
if (success){
buff.append("File successfully uploaded.\n");
}
else{
buff.append("Failed to save file.");
}
}
else{
buff.append("Invalid path.\n");
}
}
outp.write(buff.toString());
}
I am able to successfully do it with curl
curl --form userfile1=@/home/pi/src/CreateNewFolderServlet.java --form press=OK localhost:2222/pi/GetFileServlet?path="/media/"
This is the method that is supposed to have the same functionality on webapp.
@ResponseBody
@RequestMapping(value="/upload/",method=RequestMethod.POST ,produces = "text/plain")
public String uploadFile(MultipartHttpServletRequest request2, HttpServletResponse response2){
Iterator<String> itr = request2.getFileNames();
MultipartFile file = request2.getFile(itr.next());
System.out.println(file.getOriginalFilename() +" uploaded!");
System.out.println(file.toString());
MultiValueMap<String, Object> parts = new LinkedMultiValueMap<String, Object>();
parts.add("userfile1",file);
//reqEntity.addPart("userfile1", file);
String path="/public/";
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.MULTIPART_FORM_DATA);
System.out.println("1");
HttpEntity<MultiValueMap<String, Object>> request = new HttpEntity<MultiValueMap<String, Object>>(parts, headers);
String url = url2+"/pi/GetFileServlet?path="+path;
System.out.println("2");
/* restTemplate.getMessageConverters().add(new FormHttpMessageConverter());
restTemplate.getMessageConverters().add(
new MappingJackson2HttpMessageConverter());*/
System.out.println("3");
ResponseEntity<String> response = restTemplate.exchange(url, HttpMethod.POST, request,String.class);
System.out.println("4");
System.out.println("response : " +response);
if(response==null||response.getBody().trim()==""){
return "error";
}
return response.getBody();
}
This is the output that I get:
ui-elements.html uploaded!
org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile@47e7673e
1
2
3
As you can see number 4 is not printed No exception in console. Exceptions found during debugging:
org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: No serializer found for class java.io.ByteArrayInputStream and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: org.springframework.web.multipart.support.StandardMultipartFile["inputStream"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class java.io.ByteArrayInputStream and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: org.springframework.web.multipart.support.StandardMultipartFile["inputStream"])
Reading the whole file in a ByteArrayResource
can be a memory consumption issue with large files.
You can proxy a file upload in a spring mvc controller using a InputStreamResource
:
@RequestMapping(value = "/upload", method = RequestMethod.POST)
public ResponseEntity<?> uploadImages(@RequestPart("images") final MultipartFile[] files) throws IOException {
LinkedMultiValueMap<String, Object> map = new LinkedMultiValueMap<>();
String response;
HttpStatus httpStatus = HttpStatus.CREATED;
try {
for (MultipartFile file : files) {
if (!file.isEmpty()) {
map.add("images", new MultipartInputStreamFileResource(file.getInputStream(), file.getOriginalFilename()));
}
}
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.MULTIPART_FORM_DATA);
String url = "http://example.com/upload";
HttpEntity<LinkedMultiValueMap<String, Object>> requestEntity = new HttpEntity<>(map, headers);
response = restTemplate.postForObject(url, requestEntity, String.class);
} catch (HttpStatusCodeException e) {
httpStatus = HttpStatus.valueOf(e.getStatusCode().value());
response = e.getResponseBodyAsString();
} catch (Exception e) {
httpStatus = HttpStatus.INTERNAL_SERVER_ERROR;
response = e.getMessage();
}
return new ResponseEntity<>(response, httpStatus);
}
class MultipartInputStreamFileResource extends InputStreamResource {
private final String filename;
MultipartInputStreamFileResource(InputStream inputStream, String filename) {
super(inputStream);
this.filename = filename;
}
@Override
public String getFilename() {
return this.filename;
}
@Override
public long contentLength() throws IOException {
return -1; // we do not want to generally read the whole stream into memory ...
}
}