MimeTypeから拡張機能を取得する

Question

MimeTypeからextensionを取得したい。

例えば：

video/mp4 ----> mp4 application/x-rar-compressed ----> rar text/plain ----> txt application/pdf ----> pdf

WindowsまたはLinuxでファイルを保存するために、URLからファイルをダウンロードできるこの方法があります。したがって、拡張子なしで保存することしかできません（それはしたくありません）。

このメソッドではMimeType extensionは取得できません。

public void DownloadImage() { String TheFolderPath = "/home/MyPC/Downloaded"; String File_NAME = "My downloaded file"; URL fetchFile = new URL(IMAGE_URL); byte[] FileAsArray = Resources.toByteArray(fetchFile); //Getting the MimeType String MimeType = URLConnection.guessContentTypeFromStream(new ByteArrayInputStream(FileAsArray)); System.out.println(MimeType); File fileToWriteTo = new File(TheFolderPath.concat("/" + File_NAME)); //Saving the file using Guava Files.write(FileAsArray, fileToWriteTo); }

MimeTypeを使用して拡張子付きのファイルを書き込むにはどうすればよいですか？

Mindaugas Bernatavičius · Accepted Answer

一般に2つの方法があります。

mimeTypesの拡張子へのマッピングがあります。
いくつかのロジックを使用してそれを計算します。

2番目のアプローチは本当に良くないので、完成のためにのみ提供します。最初のアプローチでは、次のリソースを使用できます： https://www.freeformatter.com/mime-types-list.html

私は使うだろう HashMap<K,V>-キーはMimeTypeで、値は拡張子（または類似）です。

hermeslm · Answer

この質問の問題は、いくつかの拡張機能が同じMimeTypeを生成できること、その逆も簡単であり、たとえば、多くのutilsクラスでそれを見つけることができることです。 MimetypesFileTypeMap ですが、この便利なクラス MimeTypes と私は拡張機能を追加するちょっとしたトリックを行いました @ MindaugasBernatavičius のようなマッピングは、これがMimeTypeによってデフォルトの拡張機能を返すことを覚えておいてくださいが、不正確な場合があります。

// Copyright (c) 2003-2009, Jodd Team (jodd.org). All Rights Reserved. package co.tmunited.fs.service.util; import Java.util.HashMap; /** * Map file extensions to MIME types. Based on the Apache mime.types file. * http://www.iana.org/assignments/media-types/ */ public class MimeTypes { public static final String MIME_APPLICATION_ANDREW_INSET = "application/andrew-inset"; public static final String MIME_APPLICATION_JSON = "application/json"; public static final String MIME_APPLICATION_Zip = "application/Zip"; public static final String MIME_APPLICATION_X_GZIP = "application/x-gzip"; public static final String MIME_APPLICATION_TGZ = "application/tgz"; public static final String MIME_APPLICATION_MSWORD = "application/msword"; public static final String MIME_APPLICATION_MSWORD_2007 = "application/vnd.openxmlformats-officedocument.wordprocessingml.document"; public static final String MIME_APPLICATION_VND_TEXT = "application/vnd.oasis.opendocument.text"; public static final String MIME_APPLICATION_POSTSCRIPT = "application/postscript"; public static final String MIME_APPLICATION_PDF = "application/pdf"; public static final String MIME_APPLICATION_JNLP = "application/jnlp"; public static final String MIME_APPLICATION_MAC_BINHEX40 = "application/mac-binhex40"; public static final String MIME_APPLICATION_MAC_COMPACTPRO = "application/mac-compactpro"; public static final String MIME_APPLICATION_MATHML_XML = "application/mathml+xml"; public static final String MIME_APPLICATION_OCTET_STREAM = "application/octet-stream"; public static final String MIME_APPLICATION_ODA = "application/oda"; public static final String MIME_APPLICATION_RDF_XML = "application/rdf+xml"; public static final String MIME_APPLICATION_Java_ARCHIVE = "application/Java-archive"; public static final String MIME_APPLICATION_RDF_SMIL = "application/smil"; public static final String MIME_APPLICATION_SRGS = "application/srgs"; public static final String MIME_APPLICATION_SRGS_XML = "application/srgs+xml"; public static final String MIME_APPLICATION_VND_MIF = "application/vnd.mif"; public static final String MIME_APPLICATION_VND_MSEXCEL = "application/vnd.ms-Excel"; public static final String MIME_APPLICATION_VND_MSEXCEL_2007 = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"; public static final String MIME_APPLICATION_VND_SPREADSHEET = "application/vnd.oasis.opendocument.spreadsheet"; public static final String MIME_APPLICATION_VND_MSPOWERPOINT = "application/vnd.ms-PowerPoint"; public static final String MIME_APPLICATION_VND_RNREALMEDIA = "application/vnd.rn-realmedia"; public static final String MIME_APPLICATION_X_BCPIO = "application/x-bcpio"; public static final String MIME_APPLICATION_X_CDLINK = "application/x-cdlink"; public static final String MIME_APPLICATION_X_CHESS_PGN = "application/x-chess-pgn"; public static final String MIME_APPLICATION_X_CPIO = "application/x-cpio"; public static final String MIME_APPLICATION_X_CSH = "application/x-csh"; public static final String MIME_APPLICATION_X_DIRECTOR = "application/x-director"; public static final String MIME_APPLICATION_X_DVI = "application/x-dvi"; public static final String MIME_APPLICATION_X_FUTURESPLASH = "application/x-futuresplash"; public static final String MIME_APPLICATION_X_GTAR = "application/x-gtar"; public static final String MIME_APPLICATION_X_HDF = "application/x-hdf"; public static final String MIME_APPLICATION_X_JAVASCRIPT = "application/x-javascript"; public static final String MIME_APPLICATION_X_KOAN = "application/x-koan"; public static final String MIME_APPLICATION_X_LATEX = "application/x-latex"; public static final String MIME_APPLICATION_X_NETCDF = "application/x-netcdf"; public static final String MIME_APPLICATION_X_OGG = "application/x-ogg"; public static final String MIME_APPLICATION_X_SH = "application/x-sh"; public static final String MIME_APPLICATION_X_SHAR = "application/x-shar"; public static final String MIME_APPLICATION_X_SHOCKWAVE_FLASH = "application/x-shockwave-flash"; public static final String MIME_APPLICATION_X_STUFFIT = "application/x-stuffit"; public static final String MIME_APPLICATION_X_SV4CPIO = "application/x-sv4cpio"; public static final String MIME_APPLICATION_X_SV4CRC = "application/x-sv4crc"; public static final String MIME_APPLICATION_X_TAR = "application/x-tar"; public static final String MIME_APPLICATION_X_RAR_COMPRESSED = "application/x-rar-compressed"; public static final String MIME_APPLICATION_X_TCL = "application/x-tcl"; public static final String MIME_APPLICATION_X_TEX = "application/x-tex"; public static final String MIME_APPLICATION_X_TEXINFO = "application/x-texinfo"; public static final String MIME_APPLICATION_X_TROFF = "application/x-troff"; public static final String MIME_APPLICATION_X_TROFF_MAN = "application/x-troff-man"; public static final String MIME_APPLICATION_X_TROFF_ME = "application/x-troff-me"; public static final String MIME_APPLICATION_X_TROFF_MS = "application/x-troff-ms"; public static final String MIME_APPLICATION_X_USTAR = "application/x-ustar"; public static final String MIME_APPLICATION_X_WAIS_SOURCE = "application/x-wais-source"; public static final String MIME_APPLICATION_VND_MOZZILLA_XUL_XML = "application/vnd.mozilla.xul+xml"; public static final String MIME_APPLICATION_XHTML_XML = "application/xhtml+xml"; public static final String MIME_APPLICATION_XSLT_XML = "application/xslt+xml"; public static final String MIME_APPLICATION_XML = "application/xml"; public static final String MIME_APPLICATION_XML_DTD = "application/xml-dtd"; public static final String MIME_IMAGE_BMP = "image/bmp"; public static final String MIME_IMAGE_CGM = "image/cgm"; public static final String MIME_IMAGE_GIF = "image/gif"; public static final String MIME_IMAGE_IEF = "image/ief"; public static final String MIME_IMAGE_JPEG = "image/jpeg"; public static final String MIME_IMAGE_TIFF = "image/tiff"; public static final String MIME_IMAGE_PNG = "image/png"; public static final String MIME_IMAGE_SVG_XML = "image/svg+xml"; public static final String MIME_IMAGE_VND_DJVU = "image/vnd.djvu"; public static final String MIME_IMAGE_WAP_WBMP = "image/vnd.wap.wbmp"; public static final String MIME_IMAGE_X_CMU_RASTER = "image/x-cmu-raster"; public static final String MIME_IMAGE_X_ICON = "image/x-icon"; public static final String MIME_IMAGE_X_PORTABLE_ANYMAP = "image/x-portable-anymap"; public static final String MIME_IMAGE_X_PORTABLE_BITMAP = "image/x-portable-bitmap"; public static final String MIME_IMAGE_X_PORTABLE_GRAYMAP = "image/x-portable-graymap"; public static final String MIME_IMAGE_X_PORTABLE_PIXMAP = "image/x-portable-pixmap"; public static final String MIME_IMAGE_X_RGB = "image/x-rgb"; public static final String MIME_AUDIO_BASIC = "audio/basic"; public static final String MIME_AUDIO_MIDI = "audio/midi"; public static final String MIME_AUDIO_MPEG = "audio/mpeg"; public static final String MIME_AUDIO_X_AIFF = "audio/x-aiff"; public static final String MIME_AUDIO_X_MPEGURL = "audio/x-mpegurl"; public static final String MIME_AUDIO_X_PN_REALAUDIO = "audio/x-pn-realaudio"; public static final String MIME_AUDIO_X_WAV = "audio/x-wav"; public static final String MIME_CHEMICAL_X_PDB = "chemical/x-pdb"; public static final String MIME_CHEMICAL_X_XYZ = "chemical/x-xyz"; public static final String MIME_MODEL_IGES = "model/iges"; public static final String MIME_MODEL_MESH = "model/mesh"; public static final String MIME_MODEL_VRLM = "model/vrml"; public static final String MIME_TEXT_PLAIN = "text/plain"; public static final String MIME_TEXT_RICHTEXT = "text/richtext"; public static final String MIME_TEXT_RTF = "text/rtf"; public static final String MIME_TEXT_HTML = "text/html"; public static final String MIME_TEXT_CALENDAR = "text/calendar"; public static final String MIME_TEXT_CSS = "text/css"; public static final String MIME_TEXT_SGML = "text/sgml"; public static final String MIME_TEXT_TAB_SEPARATED_VALUES = "text/tab-separated-values"; public static final String MIME_TEXT_VND_WAP_XML = "text/vnd.wap.wml"; public static final String MIME_TEXT_VND_WAP_WMLSCRIPT = "text/vnd.wap.wmlscript"; public static final String MIME_TEXT_X_SETEXT = "text/x-setext"; public static final String MIME_TEXT_X_COMPONENT = "text/x-component"; public static final String MIME_VIDEO_QUICKTIME = "video/quicktime"; public static final String MIME_VIDEO_MPEG = "video/mpeg"; public static final String MIME_VIDEO_VND_MPEGURL = "video/vnd.mpegurl"; public static final String MIME_VIDEO_X_MSVIDEO = "video/x-msvideo"; public static final String MIME_VIDEO_X_MS_WMV = "video/x-ms-wmv"; public static final String MIME_VIDEO_X_SGI_MOVIE = "video/x-sgi-movie"; public static final String MIME_X_CONFERENCE_X_COOLTALK = "x-conference/x-cooltalk"; private static HashMap<String, String> mimeTypeMapping; private static HashMap<String, String> extMapping; static { mimeTypeMapping = new HashMap<String, String>(200) { private void put1(String key, String value) { if (put(key, value) != null) { throw new IllegalArgumentException("Duplicated extension: " + key); } } { put1("xul", MIME_APPLICATION_VND_MOZZILLA_XUL_XML); put1("json", MIME_APPLICATION_JSON); put1("ice", MIME_X_CONFERENCE_X_COOLTALK); put1("movie", MIME_VIDEO_X_SGI_MOVIE); put1("avi", MIME_VIDEO_X_MSVIDEO); put1("wmv", MIME_VIDEO_X_MS_WMV); put1("m4u", MIME_VIDEO_VND_MPEGURL); put1("mxu", MIME_VIDEO_VND_MPEGURL); put1("htc", MIME_TEXT_X_COMPONENT); put1("etx", MIME_TEXT_X_SETEXT); put1("wmls", MIME_TEXT_VND_WAP_WMLSCRIPT); put1("wml", MIME_TEXT_VND_WAP_XML); put1("tsv", MIME_TEXT_TAB_SEPARATED_VALUES); put1("sgm", MIME_TEXT_SGML); put1("sgml", MIME_TEXT_SGML); put1("css", MIME_TEXT_CSS); put1("ifb", MIME_TEXT_CALENDAR); put1("ics", MIME_TEXT_CALENDAR); put1("wrl", MIME_MODEL_VRLM); put1("vrlm", MIME_MODEL_VRLM); put1("silo", MIME_MODEL_MESH); put1("mesh", MIME_MODEL_MESH); put1("msh", MIME_MODEL_MESH); put1("iges", MIME_MODEL_IGES); put1("igs", MIME_MODEL_IGES); put1("rgb", MIME_IMAGE_X_RGB); put1("ppm", MIME_IMAGE_X_PORTABLE_PIXMAP); put1("pgm", MIME_IMAGE_X_PORTABLE_GRAYMAP); put1("pbm", MIME_IMAGE_X_PORTABLE_BITMAP); put1("pnm", MIME_IMAGE_X_PORTABLE_ANYMAP); put1("ico", MIME_IMAGE_X_ICON); put1("ras", MIME_IMAGE_X_CMU_RASTER); put1("wbmp", MIME_IMAGE_WAP_WBMP); put1("djv", MIME_IMAGE_VND_DJVU); put1("djvu", MIME_IMAGE_VND_DJVU); put1("svg", MIME_IMAGE_SVG_XML); put1("ief", MIME_IMAGE_IEF); put1("cgm", MIME_IMAGE_CGM); put1("bmp", MIME_IMAGE_BMP); put1("xyz", MIME_CHEMICAL_X_XYZ); put1("pdb", MIME_CHEMICAL_X_PDB); put1("ra", MIME_AUDIO_X_PN_REALAUDIO); put1("ram", MIME_AUDIO_X_PN_REALAUDIO); put1("m3u", MIME_AUDIO_X_MPEGURL); put1("aifc", MIME_AUDIO_X_AIFF); put1("aif", MIME_AUDIO_X_AIFF); put1("aiff", MIME_AUDIO_X_AIFF); put1("mp3", MIME_AUDIO_MPEG); put1("mp2", MIME_AUDIO_MPEG); put1("mp1", MIME_AUDIO_MPEG); put1("mpga", MIME_AUDIO_MPEG); put1("kar", MIME_AUDIO_MIDI); put1("mid", MIME_AUDIO_MIDI); put1("midi", MIME_AUDIO_MIDI); put1("dtd", MIME_APPLICATION_XML_DTD); put1("xsl", MIME_APPLICATION_XML); put1("xml", MIME_APPLICATION_XML); put1("xslt", MIME_APPLICATION_XSLT_XML); put1("xht", MIME_APPLICATION_XHTML_XML); put1("xhtml", MIME_APPLICATION_XHTML_XML); put1("src", MIME_APPLICATION_X_WAIS_SOURCE); put1("ustar", MIME_APPLICATION_X_USTAR); put1("ms", MIME_APPLICATION_X_TROFF_MS); put1("me", MIME_APPLICATION_X_TROFF_ME); put1("man", MIME_APPLICATION_X_TROFF_MAN); put1("roff", MIME_APPLICATION_X_TROFF); put1("tr", MIME_APPLICATION_X_TROFF); put1("t", MIME_APPLICATION_X_TROFF); put1("texi", MIME_APPLICATION_X_TEXINFO); put1("texinfo", MIME_APPLICATION_X_TEXINFO); put1("tex", MIME_APPLICATION_X_TEX); put1("tcl", MIME_APPLICATION_X_TCL); put1("sv4crc", MIME_APPLICATION_X_SV4CRC); put1("sv4cpio", MIME_APPLICATION_X_SV4CPIO); put1("sit", MIME_APPLICATION_X_STUFFIT); put1("swf", MIME_APPLICATION_X_SHOCKWAVE_FLASH); put1("shar", MIME_APPLICATION_X_SHAR); put1("sh", MIME_APPLICATION_X_SH); put1("cdf", MIME_APPLICATION_X_NETCDF); put1("nc", MIME_APPLICATION_X_NETCDF); put1("latex", MIME_APPLICATION_X_LATEX); put1("skm", MIME_APPLICATION_X_KOAN); put1("skt", MIME_APPLICATION_X_KOAN); put1("skd", MIME_APPLICATION_X_KOAN); put1("skp", MIME_APPLICATION_X_KOAN); put1("js", MIME_APPLICATION_X_JAVASCRIPT); put1("hdf", MIME_APPLICATION_X_HDF); put1("gtar", MIME_APPLICATION_X_GTAR); put1("spl", MIME_APPLICATION_X_FUTURESPLASH); put1("dvi", MIME_APPLICATION_X_DVI); put1("dxr", MIME_APPLICATION_X_DIRECTOR); put1("dir", MIME_APPLICATION_X_DIRECTOR); put1("dcr", MIME_APPLICATION_X_DIRECTOR); put1("csh", MIME_APPLICATION_X_CSH); put1("cpio", MIME_APPLICATION_X_CPIO); put1("pgn", MIME_APPLICATION_X_CHESS_PGN); put1("vcd", MIME_APPLICATION_X_CDLINK); put1("bcpio", MIME_APPLICATION_X_BCPIO); put1("rm", MIME_APPLICATION_VND_RNREALMEDIA); put1("ppt", MIME_APPLICATION_VND_MSPOWERPOINT); put1("mif", MIME_APPLICATION_VND_MIF); put1("grxml", MIME_APPLICATION_SRGS_XML); put1("gram", MIME_APPLICATION_SRGS); put1("smil", MIME_APPLICATION_RDF_SMIL); put1("smi", MIME_APPLICATION_RDF_SMIL); put1("rdf", MIME_APPLICATION_RDF_XML); put1("ogg", MIME_APPLICATION_X_OGG); put1("oda", MIME_APPLICATION_ODA); put1("dmg", MIME_APPLICATION_OCTET_STREAM); put1("lzh", MIME_APPLICATION_OCTET_STREAM); put1("so", MIME_APPLICATION_OCTET_STREAM); put1("lha", MIME_APPLICATION_OCTET_STREAM); put1("dms", MIME_APPLICATION_OCTET_STREAM); put1("bin", MIME_APPLICATION_OCTET_STREAM); put1("mathml", MIME_APPLICATION_MATHML_XML); put1("cpt", MIME_APPLICATION_MAC_COMPACTPRO); put1("hqx", MIME_APPLICATION_MAC_BINHEX40); put1("jnlp", MIME_APPLICATION_JNLP); put1("ez", MIME_APPLICATION_ANDREW_INSET); put1("txt", MIME_TEXT_PLAIN); put1("ini", MIME_TEXT_PLAIN); put1("c", MIME_TEXT_PLAIN); put1("h", MIME_TEXT_PLAIN); put1("cpp", MIME_TEXT_PLAIN); put1("cxx", MIME_TEXT_PLAIN); put1("cc", MIME_TEXT_PLAIN); put1("chh", MIME_TEXT_PLAIN); put1("Java", MIME_TEXT_PLAIN); put1("csv", MIME_TEXT_PLAIN); put1("bat", MIME_TEXT_PLAIN); put1("cmd", MIME_TEXT_PLAIN); put1("asc", MIME_TEXT_PLAIN); put1("rtf", MIME_TEXT_RTF); put1("rtx", MIME_TEXT_RICHTEXT); put1("html", MIME_TEXT_HTML); put1("htm", MIME_TEXT_HTML); put1("Zip", MIME_APPLICATION_Zip); put1("rar", MIME_APPLICATION_X_RAR_COMPRESSED); put1("gzip", MIME_APPLICATION_X_GZIP); put1("gz", MIME_APPLICATION_X_GZIP); put1("tgz", MIME_APPLICATION_TGZ); put1("tar", MIME_APPLICATION_X_TAR); put1("gif", MIME_IMAGE_GIF); put1("jpeg", MIME_IMAGE_JPEG); put1("jpg", MIME_IMAGE_JPEG); put1("jpe", MIME_IMAGE_JPEG); put1("tiff", MIME_IMAGE_TIFF); put1("tif", MIME_IMAGE_TIFF); put1("png", MIME_IMAGE_PNG); put1("au", MIME_AUDIO_BASIC); put1("snd", MIME_AUDIO_BASIC); put1("wav", MIME_AUDIO_X_WAV); put1("mov", MIME_VIDEO_QUICKTIME); put1("qt", MIME_VIDEO_QUICKTIME); put1("mpeg", MIME_VIDEO_MPEG); put1("mpg", MIME_VIDEO_MPEG); put1("mpe", MIME_VIDEO_MPEG); put1("abs", MIME_VIDEO_MPEG); put1("doc", MIME_APPLICATION_MSWORD); put1("docx", MIME_APPLICATION_MSWORD_2007); put1("odt", MIME_APPLICATION_VND_TEXT); put1("xls", MIME_APPLICATION_VND_MSEXCEL); put1("xlsx", MIME_APPLICATION_VND_MSEXCEL_2007); put1("ods", MIME_APPLICATION_VND_SPREADSHEET); put1("eps", MIME_APPLICATION_POSTSCRIPT); put1("ai", MIME_APPLICATION_POSTSCRIPT); put1("ps", MIME_APPLICATION_POSTSCRIPT); put1("pdf", MIME_APPLICATION_PDF); put1("exe", MIME_APPLICATION_OCTET_STREAM); put1("dll", MIME_APPLICATION_OCTET_STREAM); put1("class", MIME_APPLICATION_OCTET_STREAM); put1("jar", MIME_APPLICATION_Java_ARCHIVE); } }; } static { extMapping = new HashMap<String, String>(200) { private void put1(String key, String value) { if (put(key, value) != null) { throw new IllegalArgumentException("Duplicated Mimetype: " + key); } } { put1(MIME_APPLICATION_VND_MOZZILLA_XUL_XML, "xul"); put1(MIME_APPLICATION_JSON, "json"); put1(MIME_X_CONFERENCE_X_COOLTALK, "ice"); put1(MIME_VIDEO_X_SGI_MOVIE, "movie"); put1(MIME_VIDEO_X_MSVIDEO, "avi"); put1(MIME_VIDEO_X_MS_WMV, "wmv"); put1(MIME_VIDEO_VND_MPEGURL, "m4u"); put1(MIME_TEXT_X_COMPONENT, "htc"); put1(MIME_TEXT_X_SETEXT, "etx"); put1(MIME_TEXT_VND_WAP_WMLSCRIPT, "wmls"); put1(MIME_TEXT_VND_WAP_XML, "wml"); put1(MIME_TEXT_TAB_SEPARATED_VALUES, "tsv"); put1(MIME_TEXT_SGML, "sgml"); put1(MIME_TEXT_CSS, "css"); put1(MIME_TEXT_CALENDAR, "ics"); put1(MIME_MODEL_VRLM, "vrlm"); put1(MIME_MODEL_MESH, "mesh"); put1(MIME_MODEL_IGES, "iges"); put1(MIME_IMAGE_X_RGB, "rgb"); put1(MIME_IMAGE_X_PORTABLE_PIXMAP, "ppm"); put1(MIME_IMAGE_X_PORTABLE_GRAYMAP, "pgm"); put1(MIME_IMAGE_X_PORTABLE_BITMAP, "pbm"); put1(MIME_IMAGE_X_PORTABLE_ANYMAP, "pnm"); put1(MIME_IMAGE_X_ICON, "ico"); put1(MIME_IMAGE_X_CMU_RASTER, "ras"); put1(MIME_IMAGE_WAP_WBMP, "wbmp"); put1(MIME_IMAGE_VND_DJVU, "djvu"); put1(MIME_IMAGE_SVG_XML, "svg"); put1(MIME_IMAGE_IEF, "ief"); put1(MIME_IMAGE_CGM, "cgm"); put1(MIME_IMAGE_BMP, "bmp"); put1(MIME_CHEMICAL_X_XYZ, "xyz"); put1(MIME_CHEMICAL_X_PDB, "pdb"); put1(MIME_AUDIO_X_PN_REALAUDIO, "ra"); put1(MIME_AUDIO_X_MPEGURL, "m3u"); put1(MIME_AUDIO_X_AIFF, "aiff"); put1(MIME_AUDIO_MPEG, "mp3"); put1(MIME_AUDIO_MIDI, "midi"); put1(MIME_APPLICATION_XML_DTD, "dtd"); put1(MIME_APPLICATION_XML, "xml"); put1(MIME_APPLICATION_XSLT_XML, "xslt"); put1(MIME_APPLICATION_XHTML_XML, "xhtml"); put1(MIME_APPLICATION_X_WAIS_SOURCE, "src"); put1(MIME_APPLICATION_X_USTAR, "ustar"); put1(MIME_APPLICATION_X_TROFF_MS, "ms"); put1(MIME_APPLICATION_X_TROFF_ME, "me"); put1(MIME_APPLICATION_X_TROFF_MAN, "man"); put1(MIME_APPLICATION_X_TROFF, "roff"); put1(MIME_APPLICATION_X_TEXINFO, "texi"); put1(MIME_APPLICATION_X_TEX, "tex"); put1(MIME_APPLICATION_X_TCL, "tcl"); put1(MIME_APPLICATION_X_SV4CRC, "sv4crc"); put1(MIME_APPLICATION_X_SV4CPIO, "sv4cpio"); put1(MIME_APPLICATION_X_STUFFIT, "sit"); put1(MIME_APPLICATION_X_SHOCKWAVE_FLASH, "swf"); put1(MIME_APPLICATION_X_SHAR, "shar"); put1(MIME_APPLICATION_X_SH, "sh"); put1(MIME_APPLICATION_X_NETCDF, "cdf"); put1(MIME_APPLICATION_X_LATEX, "latex"); put1(MIME_APPLICATION_X_KOAN, "skm"); put1(MIME_APPLICATION_X_JAVASCRIPT, "js"); put1(MIME_APPLICATION_X_HDF, "hdf"); put1(MIME_APPLICATION_X_GTAR, "gtar"); put1(MIME_APPLICATION_X_FUTURESPLASH, "spl"); put1(MIME_APPLICATION_X_DVI, "dvi"); put1(MIME_APPLICATION_X_DIRECTOR, "dir"); put1(MIME_APPLICATION_X_CSH, "csh"); put1(MIME_APPLICATION_X_CPIO, "cpio"); put1(MIME_APPLICATION_X_CHESS_PGN, "pgn"); put1(MIME_APPLICATION_X_CDLINK, "vcd"); put1(MIME_APPLICATION_X_BCPIO, "bcpio"); put1(MIME_APPLICATION_VND_RNREALMEDIA, "rm"); put1(MIME_APPLICATION_VND_MSPOWERPOINT, "ppt"); put1(MIME_APPLICATION_VND_MIF, "mif"); put1(MIME_APPLICATION_SRGS_XML, "grxml"); put1(MIME_APPLICATION_SRGS, "gram"); put1(MIME_APPLICATION_RDF_SMIL, "smil"); put1(MIME_APPLICATION_RDF_XML, "rdf"); put1(MIME_APPLICATION_X_OGG, "ogg"); put1(MIME_APPLICATION_ODA, "oda"); put1(MIME_APPLICATION_MATHML_XML, "mathml"); put1(MIME_APPLICATION_MAC_COMPACTPRO, "cpt"); put1(MIME_APPLICATION_MAC_BINHEX40, "hqx"); put1(MIME_APPLICATION_JNLP, "jnlp"); put1(MIME_APPLICATION_ANDREW_INSET, "ez"); put1(MIME_TEXT_PLAIN, "txt"); put1(MIME_TEXT_RTF, "rtf"); put1(MIME_TEXT_RICHTEXT, "rtx"); put1(MIME_TEXT_HTML, "html"); put1(MIME_APPLICATION_Zip, "Zip"); put1(MIME_APPLICATION_X_RAR_COMPRESSED, "rar"); put1(MIME_APPLICATION_X_GZIP, "gzip"); put1(MIME_APPLICATION_TGZ, "tgz"); put1(MIME_APPLICATION_X_TAR, "tar"); put1(MIME_IMAGE_GIF, "gif"); put1(MIME_IMAGE_JPEG, "jpg"); put1(MIME_IMAGE_TIFF, "tiff"); put1(MIME_IMAGE_PNG, "png"); put1(MIME_AUDIO_BASIC, "au"); put1(MIME_AUDIO_X_WAV, "wav"); put1(MIME_VIDEO_QUICKTIME, "mov"); put1(MIME_VIDEO_MPEG, "mpg"); put1(MIME_APPLICATION_MSWORD, "doc"); put1(MIME_APPLICATION_MSWORD_2007, "docx"); put1(MIME_APPLICATION_VND_TEXT, "odt"); put1(MIME_APPLICATION_VND_MSEXCEL, "xls"); put1(MIME_APPLICATION_VND_SPREADSHEET, "ods"); put1(MIME_APPLICATION_POSTSCRIPT, "ps"); put1(MIME_APPLICATION_PDF, "pdf"); put1(MIME_APPLICATION_OCTET_STREAM, "exe"); put1(MIME_APPLICATION_Java_ARCHIVE, "jar"); } }; } /** * Registers MIME type for provided extension. Existing extension type will be overriden. */ public static void registerMimeType(String ext, String mimeType) { mimeTypeMapping.put(ext, mimeType); } /** * Returns the corresponding MIME type to the given extension. * If no MIME type was found it returns 'application/octet-stream' type. */ public static String getMimeType(String ext) { String mimeType = lookupMimeType(ext); if (mimeType == null) { mimeType = MIME_APPLICATION_OCTET_STREAM; } return mimeType; } /** * Simply returns MIME type or <code>null</code> if no type is found. */ public static String lookupMimeType(String ext) { return mimeTypeMapping.get(ext.toLowerCase()); } /** * Simply returns Ext or <code>null</code> if no Mimetype is found. */ public static String lookupExt(String mimeType) { return extMapping.get(mimeType.toLowerCase()); } /** * Returns the default Ext to the given MimeType. * If no MIME type was found it returns 'unknown' ext. */ public static String getDefaultExt(String mimeType) { String ext = lookupExt(mimeType); if (ext == null) { ext = "unknown"; } return ext; } }

そして、あなたはこのようにそれを使うことができます：

@Test public void mimetypePdf() throws Exception { String ext = MimeTypes.getDefaultExt(MimeTypes.MIME_APPLICATION_PDF); Assert.assertEquals("Not equals", "pdf", ext); }

Tajrib · Answer

「ミンダウガスベルナタビシウス」の提案を使用して、問題を解決するためのクラスを作成しました。

import Java.util.HashMap; public class MimeTypesAndExtensions { static HashMap<String, String> TheHashMap = new HashMap<String, String>(); public MimeTypesAndExtensions() { super(); } static { CreateHashMap(); } /***************************************************************************** Extracted from : https://www.freeformatter.com/mime-types-list.html - The "x-" prefix of a MIME subtype simply means that it's non-standard, i.e. not registered with the "Internet Assigned Numbers Authority" (IANA). - The "vnd" prefix means that the MIME value is vendor specific. *****************************************************************************/ private static void CreateHashMap() { // This list is not complete... // I got it from https://www.freeformatter.com/mime-types-list.html TheHashMap.put("application/vnd.hzn-3d-crossword", "x3d"); TheHashMap.put("application/vnd.Lotus-1-2-3", "123"); TheHashMap.put("text/vnd.in3d.3dml", "3dml"); TheHashMap.put("video/3gpp2", "3g2"); ..... TheHashMap.put("application/yin+xml", "yin"); TheHashMap.put("application/vnd.zzazz.deck+xml", "zaz"); TheHashMap.put("application/Zip", "Zip"); TheHashMap.put("application/vnd.zul", "zir"); TheHashMap.put("application/vnd.handheld-entertainment+xml", "zmm"); TheHashMap.put("application/andrew-inset", "N/A"); } public static String getExtensionFromMimeType(String TheMimeType) { String TheExtension = "Extension Not Found"; for(String key: TheHashMap.keySet()){ if(key.toLowerCase().equals(TheMimeType.toLowerCase())) { TheExtension = TheHashMap.get(key); return TheExtension; } } return TheExtension; } public static String getMimeTypeFromExtension(String TheExtension) { StringBuilder TheMimeTypes = new StringBuilder(); for(String key: TheHashMap.keySet()){ if(TheHashMap.get(key.toLowerCase()).equals(TheExtension.toLowerCase())) { TheMimeTypes.append(key.concat("
")); } } if(TheMimeTypes.length() == 0) return "MimeType Not Found"; return TheMimeTypes.toString(); } public static String getMimeTypesAndExtensions(){ StringBuilder TheMimeTypesAndExtensions = new StringBuilder(); for(String key: TheHashMap.keySet()){ TheMimeTypesAndExtensions.append(TheHashMap.get(key).concat(" -----> ").concat(key).concat("
")); } return TheMimeTypesAndExtensions.toString(); } }

igr · Answer

jodd を試してください。そのためのユーティリティがあります：MimeUtil.getMimeType()は、拡張子を取り、mimeタイプを返します。参照： https://github.com/oblac/jodd/blob/master/jodd-core/src/main/Java/jodd/net/MimeTypes.Java#L119

編集：著者をimします。