1, the variable pass is empty Cause
Two places due to:
A message header is Content-Type: setting application / json; charset = UTF-8, in fact, should be set to: application / x-www-form-urlencoded
application / json: JSON format data
application / x-www-form-urlencoded: <form encType = ""> the default encType, form form data sent is encoded as a key / value format to the format of the server (the default data submission form
Another reason this option is checked below
multipart / form-data: file upload when required in form, it is necessary to use the format
Check this option causes postdata not according to our expectations of delivery
The results show
Header set wrong, transmission parameters not found the problem, but the response data is displayed
2, message Content-Type header Introduction
In Http protocol message header, a Content-Type indicates the media type information specific to the request.
Media format types start with / application text is:
application / xhtml + xml: XHTML format
application / xml: XML data format
application / atom + xml: Atom XML format polymerization
application / json: JSON format data
application / pdf: pdf format
application / msword: Word Document Format
application / octet-stream: the stream of binary data (such as the common file download)
application / x-www-form-urlencoded: <encType = "" form> the default encType, form form data sent is encoded as a key / value to format (data format default form submission) server
text / html: HTML format
text / plain: plain text format
text / xml: XML format
image / gif: gif image format
image / jpeg: jpg image format
image / png: png image format
Another common media format is used to upload documents:
multipart / form-Data: when a file upload is required in the form, it is necessary to use the format