flutter Multipart file upload server side error: Unable to process parts as no multi-part configuration has been provided [duplicate]

Flutter:

var request = new http.MultipartRequest("POST", url);request.fields['name'] = 'John';request.files.add(http.MultipartFile.fromPath('file1','/path/to/file1.jpg',));var response = await request.send();

On server side java servlet:

 request.getParts();

throw exception:

java.lang.IllegalStateException: Unable to process parts as no multi-part configuration has been provided        at org.apache.catalina.connector.Request.parseParts(Request.java:2866)        at org.apache.catalina.connector.Request.getParts(Request.java:2834)

request.getContentType() is correct, returning "multipart/form-data; ...".