上传文件类型

https://blog.csdn.net/qq_33413264/article/details/77506468

 final String[][] MIME_MapTable={   
            //{后缀名，MIME类型}   
            {".3gp",    "video/3gpp"},   
            {".apk",    "application/vnd.android.package-archive"},   
            {".asf",    "video/x-ms-asf"},   
            {".avi",    "video/x-msvideo"},   
            {".bin",    "application/octet-stream"},   
            {".bmp",    "image/bmp"},   
            {".c",  "text/plain"},   
            {".class",  "application/octet-stream"},   
            {".conf",   "text/plain"},   
            {".cpp",    "text/plain"},   
            {".doc",    "application/msword"},   
            {".docx",   "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},   
            {".xls",    "application/vnd.ms-excel"},    
            {".xlsx",   "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},   
            {".exe",    "application/octet-stream"},   
            {".gif",    "image/gif"},   
            {".gtar",   "application/x-gtar"},   
            {".gz", "application/x-gzip"},   
            {".h",  "text/plain"},   
            {".htm",    "text/html"},   
            {".html",   "text/html"},   
            {".jar",    "application/java-archive"},   
            {".java",   "text/plain"},   
            {".jpeg",   "image/jpeg"},   
            {".jpg",    "image/jpeg"},   
            {".js", "application/x-javascript"},   
            {".log",    "text/plain"},   
            {".m3u",    "audio/x-mpegurl"},   
            {".m4a",    "audio/mp4a-latm"},   
            {".m4b",    "audio/mp4a-latm"},   
            {".m4p",    "audio/mp4a-latm"},   
            {".m4u",    "video/vnd.mpegurl"},   
            {".m4v",    "video/x-m4v"},    
            {".mov",    "video/quicktime"},   
            {".mp2",    "audio/x-mpeg"},   
            {".mp3",    "audio/x-mpeg"},   
            {".mp4",    "video/mp4"},   
            {".mpc",    "application/vnd.mpohun.certificate"},          
            {".mpe",    "video/mpeg"},     
            {".mpeg",   "video/mpeg"},     
            {".mpg",    "video/mpeg"},     
            {".mpg4",   "video/mp4"},      
            {".mpga",   "audio/mpeg"},   
            {".msg",    "application/vnd.ms-outlook"},   
            {".ogg",    "audio/ogg"},   
            {".pdf",    "application/pdf"},   
            {".png",    "image/png"},   
            {".pps",    "application/vnd.ms-powerpoint"},   
            {".ppt",    "application/vnd.ms-powerpoint"},   
            {".pptx",   "application/vnd.openxmlformats-officedocument.presentationml.presentation"},   
            {".prop",   "text/plain"},   
            {".rc", "text/plain"},   
            {".rmvb",   "audio/x-pn-realaudio"},   
            {".rtf",    "application/rtf"},   
            {".sh", "text/plain"},   
            {".tar",    "application/x-tar"},      
            {".tgz",    "application/x-compressed"},    
            {".txt",    "text/plain"},   
            {".wav",    "audio/x-wav"},   
            {".wma",    "audio/x-ms-wma"},   
            {".wmv",    "audio/x-ms-wmv"},   
            {".wps",    "application/vnd.ms-works"},   
            {".xml",    "text/plain"},   
            {".z",  "application/x-compress"},   
            {".zip",    "application/x-zip-compressed"},   
            {"",        "*/*"}     
        };   

https://blog.csdn.net/z591102/article/details/124426036

js获取文件的后缀名
const h = file.name.substring(file.name.lastIndexOf('.') + 1)