文件上传是一个比较复杂的 HTTP 请求,我们经常有这样的需求:上传头像到服务器,或者备份文件到服务器,这个时候就得用到文件上传了。

文件上传的步骤比较复杂,不像普通的 POST 请求,它需要:

  • 设置请求头
  • 设置请求体
    • 非文件参数
    • 文件参数
    • 参数结束的标记

upload file steps

我们再使用的时候,只需要把蓝色字体的修改掉即可。

我们可以在浏览器中上传一个文件(比如 png 文件),看看浏览器需要传递什么参数给服务器。

upload a png file to server

直接看 MJ 实现的代码即可:

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#define XMGBoundary @"520it"
#define XMGEncode(string) [string dataUsingEncoding:NSUTF8StringEncoding]
#define XMGNewLine [@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]
#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// 创建请求
NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/upload"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
request.HTTPMethod = @"POST";
// 设置请求头(告诉告诉服务器,这是一个文件上传的请求)
[request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", XMGBoundary] forHTTPHeaderField:@"Content-Type"];
// 设置请求体
NSMutableData *body = [NSMutableData data];
// 文件参数
/*
--分割线\r\n
Content-Disposition: form-data; name="参数名"; filename="文件名"\r\n
Content-Type: 文件的 MIMEType\r\n
\r\n
文件数据
\r\n
*/
// 分割线
[body appendData:XMGEncode(@"--")];
[body appendData:XMGEncode(XMGBoundary)];
[body appendData:XMGNewLine];
// 文件参数名
[body appendData:XMGEncode([NSString stringWithFormat:@"Content-Disposition: form-data; name=\"file\"; filename=\"test.png\""])];
[body appendData:XMGNewLine];
// 文件的类型
[body appendData:XMGEncode([NSString stringWithFormat:@"Content-Type: image/png"])];
[body appendData:XMGNewLine];
// 文件数据
[body appendData:XMGNewLine];
UIImage *image = [UIImage imageNamed:@"test"];
[body appendData:UIImagePNGRepresentation(image)];
// ⭐️将图片转换成 NSData 的还有
// 1. [body appendData:UIImageJPEGRepresentation(UIImage *image, CGFloat compressionQuality)];
// 2. [body appendData:[NSData dataWithContentsOfFile:@"/Users/xiaomage/Desktop/test.png"]];
[body appendData:XMGNewLine];
// 非文件参数
/*
--分割线\r\n
Content-Disposition: form-data; name="参数名"\r\n
\r\n
参数值
\r\n
*/
// 分割线
[body appendData:XMGEncode(@"--")];
[body appendData:XMGEncode(XMGBoundary)];
[body appendData:XMGNewLine];
// 参数名
[body appendData:XMGEncode([NSString stringWithFormat:@"Content-Disposition: form-data; name=\"username\""])];
[body appendData:XMGNewLine];
// 参数值
[body appendData:XMGNewLine];
[body appendData:XMGEncode(@"jack")];
[body appendData:XMGNewLine];
// 结束标记
/*
--分割线--\r\n
*/
[body appendData:XMGEncode(@"--")];
[body appendData:XMGEncode(XMGBoundary)];
[body appendData:XMGEncode(@"--")];
[body appendData:XMGNewLine];
request.HTTPBody = body;
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
NSLog(@"%@", [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]);
}];
}
@end
  • 部分文件的 MIMEType

部分文件的 MIMEType

Suffixes applicable Media type and subtype(s)
.3dm x-world/x-3dmf
.3dmf x-world/x-3dmf
.a application/octet-stream
.aab application/x-authorware-bin
.aam application/x-authorware-map
.aas application/x-authorware-seg
.abc text/vnd.abc
.acgi text/html
.afl video/animaflex
.ai application/postscript
.aif audio/aiff
.aif audio/x-aiff
.aifc audio/aiff
.aifc audio/x-aiff
.aiff audio/aiff
.aiff audio/x-aiff
.aim application/x-aim
.aip text/x-audiosoft-intra
.ani application/x-navi-animation
.aos application/x-nokia-9000-communicator-add-on-software
.aps application/mime
.arc application/octet-stream
.arj application/arj
.arj application/octet-stream
.art image/x-jg
.asf video/x-ms-asf
.asm text/x-asm
.asp text/asp
.asx application/x-mplayer2
.asx video/x-ms-asf
.asx video/x-ms-asf-plugin
.au audio/basic
.au audio/x-au
.avi application/x-troff-msvideo
.avi video/avi
.avi video/msvideo
.avi video/x-msvideo
.avs video/avs-video
.bcpio application/x-bcpio
.bin application/mac-binary
.bin application/macbinary
.bin application/octet-stream
.bin application/x-binary
.bin application/x-macbinary
.bm image/bmp
.bmp image/bmp
.bmp image/x-windows-bmp
.boo application/book
.book application/book
.boz application/x-bzip2
.bsh application/x-bsh
.bz application/x-bzip
.bz2 application/x-bzip2
.c text/plain
.c text/x-c
.c++ text/plain
.cat application/vnd.ms-pki.seccat
.cc text/plain
.cc text/x-c
.ccad application/clariscad
.cco application/x-cocoa
.cdf application/cdf
.cdf application/x-cdf
.cdf application/x-netcdf
.cer application/pkix-cert
.cer application/x-x509-ca-cert
.cha application/x-chat
.chat application/x-chat
.class application/java
.class application/java-byte-code
.class application/x-java-class
.com application/octet-stream
.com text/plain
.conf text/plain
.cpio application/x-cpio
.cpp text/x-c
.cpt application/mac-compactpro
.cpt application/x-compactpro
.cpt application/x-cpt
.crl application/pkcs-crl
.crl application/pkix-crl
.crt application/pkix-cert
.crt application/x-x509-ca-cert
.crt application/x-x509-user-cert
.csh application/x-csh
.csh text/x-script.csh
.css application/x-pointplus
.css text/css
.cxx text/plain
.dcr application/x-director
.deepv application/x-deepv
.def text/plain
.der application/x-x509-ca-cert
.dif video/x-dv
.dir application/x-director
.dl video/dl
.dl video/x-dl
.doc application/msword
.dot application/msword
.dp application/commonground
.drw application/drafting
.dump application/octet-stream
.dv video/x-dv
.dvi application/x-dvi
.dwf drawing/x-dwf (old)
.dwf model/vnd.dwf
.dwg application/acad
.dwg image/vnd.dwg
.dwg image/x-dwg
.dxf application/dxf
.dxf image/vnd.dwg
.dxf image/x-dwg
.dxr application/x-director
.el text/x-script.elisp
.elc application/x-bytecode.elisp (compiled elisp)
.elc application/x-elc
.env application/x-envoy
.eps application/postscript
.es application/x-esrehber
.etx text/x-setext
.evy application/envoy
.evy application/x-envoy
.exe application/octet-stream
.f text/plain
.f text/x-fortran
.f77 text/x-fortran
.f90 text/plain
.f90 text/x-fortran
.fdf application/vnd.fdf
.fif application/fractals
.fif image/fif
.fli video/fli
.fli video/x-fli
.flo image/florian
.flx text/vnd.fmi.flexstor
.fmf video/x-atomic3d-feature
.for text/plain
.for text/x-fortran
.fpx image/vnd.fpx
.fpx image/vnd.net-fpx
.frl application/freeloader
.funk audio/make
.g text/plain
.g3 image/g3fax
.gif image/gif
.gl video/gl
.gl video/x-gl
.gsd audio/x-gsm
.gsm audio/x-gsm
.gsp application/x-gsp
.gss application/x-gss
.gtar application/x-gtar
.gz application/x-compressed
.gz application/x-gzip
.gzip application/x-gzip
.gzip multipart/x-gzip
.h text/plain
.h text/x-h
.hdf application/x-hdf
.help application/x-helpfile
.hgl application/vnd.hp-hpgl
.hh text/plain
.hh text/x-h
.hlb text/x-script
.hlp application/hlp
.hlp application/x-helpfile
.hlp application/x-winhelp
.hpg application/vnd.hp-hpgl
.hpgl application/vnd.hp-hpgl
.hqx application/binhex
.hqx application/binhex4
.hqx application/mac-binhex
.hqx application/mac-binhex40
.hqx application/x-binhex40
.hqx application/x-mac-binhex40
.hta application/hta
.htc text/x-component
.htm text/html
.html text/html
.htmls text/html
.htt text/webviewhtml
.htx text/html
.ice x-conference/x-cooltalk
.ico image/x-icon
.idc text/plain
.ief image/ief
.iefs image/ief
.iges application/iges
.iges model/iges
.igs application/iges
.igs model/iges
.ima application/x-ima
.imap application/x-httpd-imap
.inf application/inf
.ins application/x-internett-signup
.ip application/x-ip2
.isu video/x-isvideo
.it audio/it
.iv application/x-inventor
.ivr i-world/i-vrml
.ivy application/x-livescreen
.jam audio/x-jam
.jav text/plain
.jav text/x-java-source
.java text/plain
.java text/x-java-source
.jcm application/x-java-commerce
.jfif image/jpeg
.jfif image/pjpeg
.jfif-tbnl image/jpeg
.jpe image/jpeg
.jpe image/pjpeg
.jpeg image/jpeg
.jpeg image/pjpeg
.jpg image/jpeg
.jpg image/pjpeg
.jps image/x-jps
.js application/x-javascript
.js application/javascript
.js application/ecmascript
.js text/javascript
.js text/ecmascript
.jut image/jutvision
.kar audio/midi
.kar music/x-karaoke
.ksh application/x-ksh
.ksh text/x-script.ksh
.la audio/nspaudio
.la audio/x-nspaudio
.lam audio/x-liveaudio
.latex application/x-latex
.lha application/lha
.lha application/octet-stream
.lha application/x-lha
.lhx application/octet-stream
.list text/plain
.lma audio/nspaudio
.lma audio/x-nspaudio
.log text/plain
.lsp application/x-lisp
.lsp text/x-script.lisp
.lst text/plain
.lsx text/x-la-asf
.ltx application/x-latex
.lzh application/octet-stream
.lzh application/x-lzh
.lzx application/lzx
.lzx application/octet-stream
.lzx application/x-lzx
.m text/plain
.m text/x-m
.m1v video/mpeg
.m2a audio/mpeg
.m2v video/mpeg
.m3u audio/x-mpequrl
.man application/x-troff-man
.map application/x-navimap
.mar text/plain
.mbd application/mbedlet
.mc$ application/x-magic-cap-package-1.0
.mcd application/mcad
.mcd application/x-mathcad
.mcf image/vasa
.mcf text/mcf
.mcp application/netmc
.me application/x-troff-me
.mht message/rfc822
.mhtml message/rfc822
.mid application/x-midi
.mid audio/midi
.mid audio/x-mid
.mid audio/x-midi
.mid music/crescendo
.mid x-music/x-midi
.midi application/x-midi
.midi audio/midi
.midi audio/x-mid
.midi audio/x-midi
.midi music/crescendo
.midi x-music/x-midi
.mif application/x-frame
.mif application/x-mif
.mime message/rfc822
.mime www/mime
.mjf audio/x-vnd.audioexplosion.mjuicemediafile
.mjpg video/x-motion-jpeg
.mm application/base64
.mm application/x-meme
.mme application/base64
.mod audio/mod
.mod audio/x-mod
.moov video/quicktime
.mov video/quicktime
.movie video/x-sgi-movie
.mp2 audio/mpeg
.mp2 audio/x-mpeg
.mp2 video/mpeg
.mp2 video/x-mpeg
.mp2 video/x-mpeq2a
.mp3 audio/mpeg3
.mp3 audio/x-mpeg-3
.mp3 video/mpeg
.mp3 video/x-mpeg
.mpa audio/mpeg
.mpa video/mpeg
.mpc application/x-project
.mpe video/mpeg
.mpeg video/mpeg
.mpg audio/mpeg
.mpg video/mpeg
.mpga audio/mpeg
.mpp application/vnd.ms-project
.mpt application/x-project
.mpv application/x-project
.mpx application/x-project
.mrc application/marc
.ms application/x-troff-ms
.mv video/x-sgi-movie
.my audio/make
.mzz application/x-vnd.audioexplosion.mzz
.nap image/naplps
.naplps image/naplps
.nc application/x-netcdf
.ncm application/vnd.nokia.configuration-message
.nif image/x-niff
.niff image/x-niff
.nix application/x-mix-transfer
.nsc application/x-conference
.nvd application/x-navidoc
.o application/octet-stream
.oda application/oda
.omc application/x-omc
.omcd application/x-omcdatamaker
.omcr application/x-omcregerator
.p text/x-pascal
.p10 application/pkcs10
.p10 application/x-pkcs10
.p12 application/pkcs-12
.p12 application/x-pkcs12
.p7a application/x-pkcs7-signature
.p7c application/pkcs7-mime
.p7c application/x-pkcs7-mime
.p7m application/pkcs7-mime
.p7m application/x-pkcs7-mime
.p7r application/x-pkcs7-certreqresp
.p7s application/pkcs7-signature
.part application/pro_eng
.pas text/pascal
.pbm image/x-portable-bitmap
.pcl application/vnd.hp-pcl
.pcl application/x-pcl
.pct image/x-pict
.pcx image/x-pcx
.pdb chemical/x-pdb
.pdf application/pdf
.pfunk audio/make
.pfunk audio/make.my.funk
.pgm image/x-portable-graymap
.pgm image/x-portable-greymap
.pic image/pict
.pict image/pict
.pkg application/x-newton-compatible-pkg
.pko application/vnd.ms-pki.pko
.pl text/plain
.pl text/x-script.perl
.plx application/x-pixclscript
.pm image/x-xpixmap
.pm text/x-script.perl-module
.pm4 application/x-pagemaker
.pm5 application/x-pagemaker
.png image/png
.pnm application/x-portable-anymap
.pnm image/x-portable-anymap
.pot application/mspowerpoint
.pot application/vnd.ms-powerpoint
.pov model/x-pov
.ppa application/vnd.ms-powerpoint
.ppm image/x-portable-pixmap
.pps application/mspowerpoint
.pps application/vnd.ms-powerpoint
.ppt application/mspowerpoint
.ppt application/powerpoint
.ppt application/vnd.ms-powerpoint
.ppt application/x-mspowerpoint
.ppz application/mspowerpoint
.pre application/x-freelance
.prt application/pro_eng
.ps application/postscript
.psd application/octet-stream
.pvu paleovu/x-pv
.pwz application/vnd.ms-powerpoint
.py text/x-script.phyton
.pyc application/x-bytecode.python
.qcp audio/vnd.qcelp
.qd3 x-world/x-3dmf
.qd3d x-world/x-3dmf
.qif image/x-quicktime
.qt video/quicktime
.qtc video/x-qtc
.qti image/x-quicktime
.qtif image/x-quicktime
.ra audio/x-pn-realaudio
.ra audio/x-pn-realaudio-plugin
.ra audio/x-realaudio
.ram audio/x-pn-realaudio
.ras application/x-cmu-raster
.ras image/cmu-raster
.ras image/x-cmu-raster
.rast image/cmu-raster
.rexx text/x-script.rexx
.rf image/vnd.rn-realflash
.rgb image/x-rgb
.rm application/vnd.rn-realmedia
.rm audio/x-pn-realaudio
.rmi audio/mid
.rmm audio/x-pn-realaudio
.rmp audio/x-pn-realaudio
.rmp audio/x-pn-realaudio-plugin
.rng application/ringing-tones
.rng application/vnd.nokia.ringing-tone
.rnx application/vnd.rn-realplayer
.roff application/x-troff
.rp image/vnd.rn-realpix
.rpm audio/x-pn-realaudio-plugin
.rt text/richtext
.rt text/vnd.rn-realtext
.rtf application/rtf
.rtf application/x-rtf
.rtf text/richtext
.rtx application/rtf
.rtx text/richtext
.rv video/vnd.rn-realvideo
.s text/x-asm
.s3m audio/s3m
.saveme application/octet-stream
.sbk application/x-tbook
.scm application/x-lotusscreencam
.scm text/x-script.guile
.scm text/x-script.scheme
.scm video/x-scm
.sdml text/plain
.sdp application/sdp
.sdp application/x-sdp
.sdr application/sounder
.sea application/sea
.sea application/x-sea
.set application/set
.sgm text/sgml
.sgm text/x-sgml
.sgml text/sgml
.sgml text/x-sgml
.sh application/x-bsh
.sh application/x-sh
.sh application/x-shar
.sh text/x-script.sh
.shar application/x-bsh
.shar application/x-shar
.shtml text/html
.shtml text/x-server-parsed-html
.sid audio/x-psid
.sit application/x-sit
.sit application/x-stuffit
.skd application/x-koan
.skm application/x-koan
.skp application/x-koan
.skt application/x-koan
.sl application/x-seelogo
.smi application/smil
.smil application/smil
.snd audio/basic
.snd audio/x-adpcm
.sol application/solids
.spc application/x-pkcs7-certificates
.spc text/x-speech
.spl application/futuresplash
.spr application/x-sprite
.sprite application/x-sprite
.src application/x-wais-source
.ssi text/x-server-parsed-html
.ssm application/streamingmedia
.sst application/vnd.ms-pki.certstore
.step application/step
.stl application/sla
.stl application/vnd.ms-pki.stl
.stl application/x-navistyle
.stp application/step
.sv4cpio application/x-sv4cpio
.sv4crc application/x-sv4crc
.svf image/vnd.dwg
.svf image/x-dwg
.svr application/x-world
.svr x-world/x-svr
.swf application/x-shockwave-flash
.t application/x-troff
.talk text/x-speech
.tar application/x-tar
.tbk application/toolbook
.tbk application/x-tbook
.tcl application/x-tcl
.tcl text/x-script.tcl
.tcsh text/x-script.tcsh
.tex application/x-tex
.texi application/x-texinfo
.texinfo application/x-texinfo
.text application/plain
.text text/plain
.tgz application/gnutar
.tgz application/x-compressed
.tif image/tiff
.tif image/x-tiff
.tiff image/tiff
.tiff image/x-tiff
.tr application/x-troff
.tsi audio/tsp-audio
.tsp application/dsptype
.tsp audio/tsplayer
.tsv text/tab-separated-values
.turbot image/florian
.txt text/plain
.uil text/x-uil
.uni text/uri-list
.unis text/uri-list
.unv application/i-deas
.uri text/uri-list
.uris text/uri-list
.ustar application/x-ustar
.ustar multipart/x-ustar
.uu application/octet-stream
.uu text/x-uuencode
.uue text/x-uuencode
.vcd application/x-cdlink
.vcs text/x-vcalendar
.vda application/vda
.vdo video/vdo
.vew application/groupwise
.viv video/vivo
.viv video/vnd.vivo
.vivo video/vivo
.vivo video/vnd.vivo
.vmd application/vocaltec-media-desc
.vmf application/vocaltec-media-file
.voc audio/voc
.voc audio/x-voc
.vos video/vosaic
.vox audio/voxware
.vqe audio/x-twinvq-plugin
.vqf audio/x-twinvq
.vql audio/x-twinvq-plugin
.vrml application/x-vrml
.vrml model/vrml
.vrml x-world/x-vrml
.vrt x-world/x-vrt
.vsd application/x-visio
.vst application/x-visio
.vsw application/x-visio
.w60 application/wordperfect6.0
.w61 application/wordperfect6.1
.w6w application/msword
.wav audio/wav
.wav audio/x-wav
.wb1 application/x-qpro
.wbmp image/vnd.wap.wbmp
.web application/vnd.xara
.wiz application/msword
.wk1 application/x-123
.wmf windows/metafile
.wml text/vnd.wap.wml
.wmlc application/vnd.wap.wmlc
.wmls text/vnd.wap.wmlscript
.wmlsc application/vnd.wap.wmlscriptc
.word application/msword
.wp application/wordperfect
.wp5 application/wordperfect
.wp5 application/wordperfect6.0
.wp6 application/wordperfect
.wpd application/wordperfect
.wpd application/x-wpwin
.wq1 application/x-lotus
.wri application/mswrite
.wri application/x-wri
.wrl application/x-world
.wrl model/vrml
.wrl x-world/x-vrml
.wrz model/vrml
.wrz x-world/x-vrml
.wsc text/scriplet
.wsrc application/x-wais-source
.wtk application/x-wintalk
.xbm image/x-xbitmap
.xbm image/x-xbm
.xbm image/xbm
.xdr video/x-amt-demorun
.xgz xgl/drawing
.xif image/vnd.xiff
.xl application/excel
.xla application/excel
.xla application/x-excel
.xla application/x-msexcel
.xlb application/excel
.xlb application/vnd.ms-excel
.xlb application/x-excel
.xlc application/excel
.xlc application/vnd.ms-excel
.xlc application/x-excel
.xld application/excel
.xld application/x-excel
.xlk application/excel
.xlk application/x-excel
.xll application/excel
.xll application/vnd.ms-excel
.xll application/x-excel
.xlm application/excel
.xlm application/vnd.ms-excel
.xlm application/x-excel
.xls application/excel
.xls application/vnd.ms-excel
.xls application/x-excel
.xls application/x-msexcel
.xlt application/excel
.xlt application/x-excel
.xlv application/excel
.xlv application/x-excel
.xlw application/excel
.xlw application/vnd.ms-excel
.xlw application/x-excel
.xlw application/x-msexcel
.xm audio/xm
.xml application/xml
.xml text/xml
.xmz xgl/movie
.xpix application/x-vnd.ls-xpix
.xpm image/x-xpixmap
.xpm image/xpm
.x-png image/png
.xsr video/x-amt-showrun
.xwd image/x-xwd
.xwd image/x-xwindowdump
.xyz chemical/x-pdb
.z application/x-compress
.z application/x-compressed
.zip application/x-compressed
.zip application/x-zip-compressed
.zip application/zip
.zip multipart/x-zip
.zoo application/octet-stream
.zsh text/x-script.zsh
  • 通过代码获取 MIMEType

第一种做法,直接往这个文件发送一个请求:

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NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"file:///Users/apple/Downloads/PPT/file.pptx"]];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
NSLog(@"%@", response.MIMEType);
}];
// 打印得到的 MIMEType
application/vnd.openxmlformats-officedocument.presentationml.presentation

如果我们想立刻返回这个文件的 MIMEType,其实不需要发异步请求,直接发一个同步请求即可:

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// 本地 URL 还可以这样写:[NSURL fileURLWithPath:@"/Users/apple/Downloads/PPT/file.pptx"];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"file:///Users/apple/Downloads/PPT/file.pptx"]];
NSURLResponse *response = nil;
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
NSLog(@"data's length = %zd, MIMEType = %@", data.length, response.MIMEType);

还有一种做法就是直接用 C语言的 API:

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// 1. 需要在 Target -> Linked Frameworks and Libraries 引入 MobileCoreServices.framework
// 2. #import <MobileCoreServices/MobileCoreServices.h>
+ (NSString *)mimeTypeForFileAtPath:(NSString *)path {
if (![[NSFileManager defaultManager] fileExistsAtPath:path]) {
return nil;
}
CFStringRef UTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, (__bridge CFStringRef)[path pathExtension], NULL);
CFStringRef MIMEType = UTTypeCopyPreferredTagWithClass (UTI, kUTTagClassMIMEType);
CFRelease(UTI);
if (!MIMEType) {
return @"application/octet-stream";
}
return (__bridge NSString *)MIMEType; // 将 Core Foundation 的字符串转换成 Foundation 的字符串,反过来也是一样
}
// 调用:
NSLog(@"%@", [ViewController mimeTypeForFileAtPath:@"/Users/apple/Downloads/PPT/file.pptx"]);