表单提交上传文件

the request was rejected because no multipart boundary was found

org.apache.tomcat.util.http.fileupload.FileUploadException: the request was rejected because no multipart boundary was found
    org.apache.tomcat.util.http.fileupload.FileUploadBase$FileItemIteratorImpl.<init>(FileUploadBase.java:840)
    org.apache.tomcat.util.http.fileupload.FileUploadBase.getItemIterator(FileUploadBase.java:259)
    org.apache.tomcat.util.http.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:283)
    org.apache.catalina.connector.Request.parseParts(Request.java:2811)
    org.apache.catalina.connector.Request.getParts(Request.java:2729)
    org.apache.catalina.connector.RequestFacade.getParts(RequestFacade.java:1075)

问题： form表单提交，包含了文件上传 和普通的key value 字段， 报了上诉的错误。

POST /xc/dispatcher HTTP/1.1
Host: localhost:8080
Cache-Control: no-cache
Postman-Token: 15b6f371-5cd5-ed7a-8a7e-063bc442f581
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW

------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="request"

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
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="1.png"
Content-Type: image/png


------WebKitFormBoundary7MA4YWxkTrZu0gW--

去除Content-Type后：
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW

手动设置后header：
Content-Type: multipart/form-data

解决方案：
request header中不需要手动添加Content-Type（multipart/form-data），故去除header中Content-Type即可.