Spring Boot 报错 the request was rejected because no multipart boundary was found

错误信息

the request was rejected because no multipart boundary was found

org.springframework.web.multipart.MultipartException: Failed to parse multipart servlet request
    at org.springframework.web.multipart.support.StandardMultipartHttpServletRequest.handleParseFailure(StandardMultipartHttpServletRequest.java:122)
    at org.springframework.web.multipart.support.StandardMultipartHttpServletRequest.parseRequest(StandardMultipartHttpServletRequest.java:110)
    at org.springframework.web.multipart.support.StandardMultipartHttpServletRequest.<init>(StandardMultipartHttpServletRequest.java:86)
    at org.springframework.web.multipart.support.StandardServletMultipartResolver.resolveMultipart(StandardServletMultipartResolver.java:112)

Caused by: org.apache.tomcat.util.http.fileupload.FileUploadException: the request was rejected because no multipart boundary was found
    at org.apache.tomcat.util.http.fileupload.impl.FileItemIteratorImpl.init(FileItemIteratorImpl.java:189)
    at org.apache.tomcat.util.http.fileupload.impl.FileItemIteratorImpl.getMultiPartStream(FileItemIteratorImpl.java:205)
    at org.apache.tomcat.util.http.fileupload.impl.FileItemIteratorImpl.findNextItem(FileItemIteratorImpl.java:224)
    at org.apache.tomcat.util.http.fileupload.impl.FileItemIteratorImpl.<init>(FileItemIteratorImpl.java:142)
    at org.apache.tomcat.util.http.fileupload.FileUploadBase.getItemIterator(FileUploadBase.java:252)
    at org.apache.tomcat.util.http.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:276)
    at org.apache.catalina.connector.Request.parseParts(Request.java:2800)
    at org.apache.catalina.connector.Request.getParts(Request.java:2701)
    at org.apache.catalina.connector.RequestFacade.getParts(RequestFacade.java:774)

问题原因

前端上传文件时，手动设置了Content-Type。

Content-Type: multipart/form-data;

解决方法

前端无需手动设置Content-Type，浏览器会自动加上boundary。

Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryBM8Ye5Bu7Y1OUqAf