Estou procurando nas bibliotecas padrão (como apache commons, jax, jboss, javax) uma interface ou enumeração que lista os valores de todo o tipo mime padrão (também conhecido como tipo de conteúdo).

Essa interface não deve ser sobrecarregada com outras classes que dificultariam a inclusão de todo o grupo como código-fonte gwt.

por exemplo

interface ContentType{
  String JSON = "Application/JSON";
  blah ... blah ...
}

ou,

enum ContentType{
  JSON("Application/JSON"),
  blah ... blah ...
}

GoiabaBiblioteca de

Temos uma classe Guava para isso:com.google.common.net.MediaType .

Foi lançado com o Guava 12, conforme indicado no código-fonte e na edição 823 . Fontes também estão disponíveis.

Em https://docs.oracle.com/javaee/7/api/javax/ws/rs/core/MediaType.html :

staticjava.lang.String APPLICATION_ATOM_XML             "application/atom+xml"
staticMediaType        APPLICATION_ATOM_XML_TYPE        "application/atom+xml"
staticjava.lang.String APPLICATION_FORM_URLENCODED      "application/x-www-form-urlencoded"
staticMediaType        APPLICATION_FORM_URLENCODED_TYPE "application/x-www-form-urlencoded"
staticjava.lang.String APPLICATION_JSON                 "application/json"
staticMediaType        APPLICATION_JSON_TYPE            "application/json"
staticjava.lang.String APPLICATION_OCTET_STREAM         "application/octet-stream"
staticMediaType        APPLICATION_OCTET_STREAM_TYPE    "application/octet-stream"
staticjava.lang.String APPLICATION_SVG_XML              "application/svg+xml"
staticMediaType        APPLICATION_SVG_XML_TYPE         "application/svg+xml"
staticjava.lang.String APPLICATION_XHTML_XML            "application/xhtml+xml"
staticMediaType        APPLICATION_XHTML_XML_TYPE       "application/xhtml+xml"
staticjava.lang.String APPLICATION_XML                  "application/xml"
staticMediaType        APPLICATION_XML_TYPE             "application/xml"
staticjava.lang.String MEDIA_TYPE_WILDCARD              The value of a type or subtype wildcard: "*"
staticjava.lang.String MULTIPART_FORM_DATA              "multipart/form-data"
staticMediaType        MULTIPART_FORM_DATA_TYPE         "multipart/form-data"
staticjava.lang.String TEXT_HTML                        "text/html"
staticMediaType        TEXT_HTML_TYPE                   "text/html"
staticjava.lang.String TEXT_PLAIN                       "text/plain"
staticMediaType        TEXT_PLAIN_TYPE                  "text/plain"
staticjava.lang.String TEXT_XML                         "text/xml"
staticMediaType        TEXT_XML_TYPE                    "text/xml"
staticjava.lang.String WILDCARD                         "*/*"
staticMediaType        WILDCARD_TYPE                    "*/*"

Se você estiver usando o Spring Framework , haverá uma classe MediaType para tipos de conteúdo comuns:

MediaType.TEXT_HTML 
MediaType.TEXT_PLAIN 
MediaType.TEXT_XML 
MediaType.APPLICATION_JSON 
MediaType.IMAGE_JPEG 
...

Agora também há a classe org.apache.http.entity.ContentTypefrom package org.apache.httpcomponents.httpcore, iniciando em 4.2.

javax.ws.rs.core.MediaTypede JAX-RS

Java 7 para o resgate!

Você pode passar o arquivo ou o nome do arquivo e ele retornará o tipo MIME.

String mimeType = MimetypesFileTypeMap
    .getDefaultFileTypeMap()
    .getContentType(attachment.getFileName());

http://docs.oracle.com/javase/7/docs/api/javax/activation/MimetypesFileTypeMap.html

Há também uma MediaTypeclasse nas anotações do Android , caso você queira usar com o Android! Veja aqui .

Se você está no Android, tem várias opções, sendo que apenas a primeira é uma espécie de "enum":

• HTTP(que foi descontinuado na API 22), por exemplo
  HTTP.PLAIN_TEXT_TYPEou
• MimeTypeMap, por exemplo
  final String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
  Veja também FileProvider.getType().
• URLConnection que fornece os seguintes métodos:
  • guessContentTypeFromStream(InputStream is)
  • guessContentTypeFromName(String url)
  • getFileNameMap()

Por exemplo

@Override
public String getType(Uri uri) {
    return URLConnection.getFileNameMap().getContentTypeFor(
            uri.getLastPathSegment());
}

Conforme indicado na resposta acima, você pode usar javax.ws.rs.core.MediaType as constantes necessárias.

Eu também queria compartilhar um link muito legal e útil que achei que fornece uma referência a todas as constantes Javax em um só lugar - https://docs.oracle.com/javaee/7/api/constant-values.html .

Eu resolvi isso com uma classe estática:

@SuppressWarnings("serial")
public class MimeTypes {

    private static final HashMap<String, String> mimeTypes;

    static {
        mimeTypes = new HashMap<String, String>() {
            {
                put(".323", "text/h323");
                put(".3g2", "video/3gpp2");
                put(".3gp", "video/3gpp");
                put(".3gp2", "video/3gpp2");
                put(".3gpp", "video/3gpp");
                put(".7z", "application/x-7z-compressed");
                put(".aa", "audio/audible");
                put(".AAC", "audio/aac");
                put(".aaf", "application/octet-stream");
                put(".aax", "audio/vnd.audible.aax");
                put(".ac3", "audio/ac3");
                put(".aca", "application/octet-stream");
                put(".accda", "application/msaccess.addin");
                put(".accdb", "application/msaccess");
                put(".accdc", "application/msaccess.cab");
                put(".accde", "application/msaccess");
                put(".accdr", "application/msaccess.runtime");
                put(".accdt", "application/msaccess");
                put(".accdw", "application/msaccess.webapplication");
                put(".accft", "application/msaccess.ftemplate");
                put(".acx", "application/internet-property-stream");
                put(".AddIn", "text/xml");
                put(".ade", "application/msaccess");
                put(".adobebridge", "application/x-bridge-url");
                put(".adp", "application/msaccess");
                put(".ADT", "audio/vnd.dlna.adts");
                put(".ADTS", "audio/aac");
                put(".afm", "application/octet-stream");
                put(".ai", "application/postscript");
                put(".aif", "audio/x-aiff");
                put(".aifc", "audio/aiff");
                put(".aiff", "audio/aiff");
                put(".air", "application/vnd.adobe.air-application-installer-package+zip");
                put(".amc", "application/x-mpeg");
                put(".application", "application/x-ms-application");
                put(".art", "image/x-jg");
                put(".asa", "application/xml");
                put(".asax", "application/xml");
                put(".ascx", "application/xml");
                put(".asd", "application/octet-stream");
                put(".asf", "video/x-ms-asf");
                put(".ashx", "application/xml");
                put(".asi", "application/octet-stream");
                put(".asm", "text/plain");
                put(".asmx", "application/xml");
                put(".aspx", "application/xml");
                put(".asr", "video/x-ms-asf");
                put(".asx", "video/x-ms-asf");
                put(".atom", "application/atom+xml");
                put(".au", "audio/basic");
                put(".avi", "video/x-msvideo");
                put(".axs", "application/olescript");
                put(".bas", "text/plain");
                put(".bcpio", "application/x-bcpio");
                put(".bin", "application/octet-stream");
                put(".bmp", "image/bmp");
                put(".c", "text/plain");
                put(".cab", "application/octet-stream");
                put(".caf", "audio/x-caf");
                put(".calx", "application/vnd.ms-office.calx");
                put(".cat", "application/vnd.ms-pki.seccat");
                put(".cc", "text/plain");
                put(".cd", "text/plain");
                put(".cdda", "audio/aiff");
                put(".cdf", "application/x-cdf");
                put(".cer", "application/x-x509-ca-cert");
                put(".chm", "application/octet-stream");
                put(".class", "application/x-java-applet");
                put(".clp", "application/x-msclip");
                put(".cmx", "image/x-cmx");
                put(".cnf", "text/plain");
                put(".cod", "image/cis-cod");
                put(".config", "application/xml");
                put(".contact", "text/x-ms-contact");
                put(".coverage", "application/xml");
                put(".cpio", "application/x-cpio");
                put(".cpp", "text/plain");
                put(".crd", "application/x-mscardfile");
                put(".crl", "application/pkix-crl");
                put(".crt", "application/x-x509-ca-cert");
                put(".cs", "text/plain");
                put(".csdproj", "text/plain");
                put(".csh", "application/x-csh");
                put(".csproj", "text/plain");
                put(".css", "text/css");
                put(".csv", "text/csv");
                put(".cur", "application/octet-stream");
                put(".cxx", "text/plain");
                put(".dat", "application/octet-stream");
                put(".datasource", "application/xml");
                put(".dbproj", "text/plain");
                put(".dcr", "application/x-director");
                put(".def", "text/plain");
                put(".deploy", "application/octet-stream");
                put(".der", "application/x-x509-ca-cert");
                put(".dgml", "application/xml");
                put(".dib", "image/bmp");
                put(".dif", "video/x-dv");
                put(".dir", "application/x-director");
                put(".disco", "text/xml");
                put(".dll", "application/x-msdownload");
                put(".dll.config", "text/xml");
                put(".dlm", "text/dlm");
                put(".doc", "application/msword");
                put(".docm", "application/vnd.ms-word.document.macroEnabled.12");
                put(".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document");
                put(".dot", "application/msword");
                put(".dotm", "application/vnd.ms-word.template.macroEnabled.12");
                put(".dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template");
                put(".dsp", "application/octet-stream");
                put(".dsw", "text/plain");
                put(".dtd", "text/xml");
                put(".dtsConfig", "text/xml");
                put(".dv", "video/x-dv");
                put(".dvi", "application/x-dvi");
                put(".dwf", "drawing/x-dwf");
                put(".dwp", "application/octet-stream");
                put(".dxr", "application/x-director");
                put(".eml", "message/rfc822");
                put(".emz", "application/octet-stream");
                put(".eot", "application/octet-stream");
                put(".eps", "application/postscript");
                put(".etl", "application/etl");
                put(".etx", "text/x-setext");
                put(".evy", "application/envoy");
                put(".exe", "application/octet-stream");
                put(".exe.config", "text/xml");
                put(".fdf", "application/vnd.fdf");
                put(".fif", "application/fractals");
                put(".filters", "Application/xml");
                put(".fla", "application/octet-stream");
                put(".flr", "x-world/x-vrml");
                put(".flv", "video/x-flv");
                put(".fsscript", "application/fsharp-script");
                put(".fsx", "application/fsharp-script");
                put(".generictest", "application/xml");
                put(".gif", "image/gif");
                put(".group", "text/x-ms-group");
                put(".gsm", "audio/x-gsm");
                put(".gtar", "application/x-gtar");
                put(".gz", "application/x-gzip");
                put(".h", "text/plain");
                put(".hdf", "application/x-hdf");
                put(".hdml", "text/x-hdml");
                put(".hhc", "application/x-oleobject");
                put(".hhk", "application/octet-stream");
                put(".hhp", "application/octet-stream");
                put(".hlp", "application/winhlp");
                put(".hpp", "text/plain");
                put(".hqx", "application/mac-binhex40");
                put(".hta", "application/hta");
                put(".htc", "text/x-component");
                put(".htm", "text/html");
                put(".html", "text/html");
                put(".htt", "text/webviewhtml");
                put(".hxa", "application/xml");
                put(".hxc", "application/xml");
                put(".hxd", "application/octet-stream");
                put(".hxe", "application/xml");
                put(".hxf", "application/xml");
                put(".hxh", "application/octet-stream");
                put(".hxi", "application/octet-stream");
                put(".hxk", "application/xml");
                put(".hxq", "application/octet-stream");
                put(".hxr", "application/octet-stream");
                put(".hxs", "application/octet-stream");
                put(".hxt", "text/html");
                put(".hxv", "application/xml");
                put(".hxw", "application/octet-stream");
                put(".hxx", "text/plain");
                put(".i", "text/plain");
                put(".ico", "image/x-icon");
                put(".ics", "application/octet-stream");
                put(".idl", "text/plain");
                put(".ief", "image/ief");
                put(".iii", "application/x-iphone");
                put(".inc", "text/plain");
                put(".inf", "application/octet-stream");
                put(".inl", "text/plain");
                put(".ins", "application/x-internet-signup");
                put(".ipa", "application/x-itunes-ipa");
                put(".ipg", "application/x-itunes-ipg");
                put(".ipproj", "text/plain");
                put(".ipsw", "application/x-itunes-ipsw");
                put(".iqy", "text/x-ms-iqy");
                put(".isp", "application/x-internet-signup");
                put(".ite", "application/x-itunes-ite");
                put(".itlp", "application/x-itunes-itlp");
                put(".itms", "application/x-itunes-itms");
                put(".itpc", "application/x-itunes-itpc");
                put(".IVF", "video/x-ivf");
                put(".jar", "application/java-archive");
                put(".java", "application/octet-stream");
                put(".jck", "application/liquidmotion");
                put(".jcz", "application/liquidmotion");
                put(".jfif", "image/pjpeg");
                put(".jnlp", "application/x-java-jnlp-file");
                put(".jpb", "application/octet-stream");
                put(".jpe", "image/jpeg");
                put(".jpeg", "image/jpeg");
                put(".jpg", "image/jpeg");
                put(".js", "application/x-javascript");
                put(".json", "application/json");
                put(".jsx", "text/jscript");
                put(".jsxbin", "text/plain");
                put(".latex", "application/x-latex");
                put(".library-ms", "application/windows-library+xml");
                put(".lit", "application/x-ms-reader");
                put(".loadtest", "application/xml");
                put(".lpk", "application/octet-stream");
                put(".lsf", "video/x-la-asf");
                put(".lst", "text/plain");
                put(".lsx", "video/x-la-asf");
                put(".lzh", "application/octet-stream");
                put(".m13", "application/x-msmediaview");
                put(".m14", "application/x-msmediaview");
                put(".m1v", "video/mpeg");
                put(".m2t", "video/vnd.dlna.mpeg-tts");
                put(".m2ts", "video/vnd.dlna.mpeg-tts");
                put(".m2v", "video/mpeg");
                put(".m3u", "audio/x-mpegurl");
                put(".m3u8", "audio/x-mpegurl");
                put(".m4a", "audio/m4a");
                put(".m4b", "audio/m4b");
                put(".m4p", "audio/m4p");
                put(".m4r", "audio/x-m4r");
                put(".m4v", "video/x-m4v");
                put(".mac", "image/x-macpaint");
                put(".mak", "text/plain");
                put(".man", "application/x-troff-man");
                put(".manifest", "application/x-ms-manifest");
                put(".map", "text/plain");
                put(".master", "application/xml");
                put(".mda", "application/msaccess");
                put(".mdb", "application/x-msaccess");
                put(".mde", "application/msaccess");
                put(".mdp", "application/octet-stream");
                put(".me", "application/x-troff-me");
                put(".mfp", "application/x-shockwave-flash");
                put(".mht", "message/rfc822");
                put(".mhtml", "message/rfc822");
                put(".mid", "audio/mid");
                put(".midi", "audio/mid");
                put(".mix", "application/octet-stream");
                put(".mk", "text/plain");
                put(".mmf", "application/x-smaf");
                put(".mno", "text/xml");
                put(".mny", "application/x-msmoney");
                put(".mod", "video/mpeg");
                put(".mov", "video/quicktime");
                put(".movie", "video/x-sgi-movie");
                put(".mp2", "video/mpeg");
                put(".mp2v", "video/mpeg");
                put(".mp3", "audio/mpeg");
                put(".mp4", "video/mp4");
                put(".mp4v", "video/mp4");
                put(".mpa", "video/mpeg");
                put(".mpe", "video/mpeg");
                put(".mpeg", "video/mpeg");
                put(".mpf", "application/vnd.ms-mediapackage");
                put(".mpg", "video/mpeg");
                put(".mpp", "application/vnd.ms-project");
                put(".mpv2", "video/mpeg");
                put(".mqv", "video/quicktime");
                put(".ms", "application/x-troff-ms");
                put(".msi", "application/octet-stream");
                put(".mso", "application/octet-stream");
                put(".mts", "video/vnd.dlna.mpeg-tts");
                put(".mtx", "application/xml");
                put(".mvb", "application/x-msmediaview");
                put(".mvc", "application/x-miva-compiled");
                put(".mxp", "application/x-mmxp");
                put(".nc", "application/x-netcdf");
                put(".nsc", "video/x-ms-asf");
                put(".nws", "message/rfc822");
                put(".ocx", "application/octet-stream");
                put(".oda", "application/oda");
                put(".odc", "text/x-ms-odc");
                put(".odh", "text/plain");
                put(".odl", "text/plain");
                put(".odp", "application/vnd.oasis.opendocument.presentation");
                put(".ods", "application/oleobject");
                put(".odt", "application/vnd.oasis.opendocument.text");
                put(".one", "application/onenote");
                put(".onea", "application/onenote");
                put(".onepkg", "application/onenote");
                put(".onetmp", "application/onenote");
                put(".onetoc", "application/onenote");
                put(".onetoc2", "application/onenote");
                put(".orderedtest", "application/xml");
                put(".osdx", "application/opensearchdescription+xml");
                put(".p10", "application/pkcs10");
                put(".p12", "application/x-pkcs12");
                put(".p7b", "application/x-pkcs7-certificates");
                put(".p7c", "application/pkcs7-mime");
                put(".p7m", "application/pkcs7-mime");
                put(".p7r", "application/x-pkcs7-certreqresp");
                put(".p7s", "application/pkcs7-signature");
                put(".pbm", "image/x-portable-bitmap");
                put(".pcast", "application/x-podcast");
                put(".pct", "image/pict");
                put(".pcx", "application/octet-stream");
                put(".pcz", "application/octet-stream");
                put(".pdf", "application/pdf");
                put(".pfb", "application/octet-stream");
                put(".pfm", "application/octet-stream");
                put(".pfx", "application/x-pkcs12");
                put(".pgm", "image/x-portable-graymap");
                put(".pic", "image/pict");
                put(".pict", "image/pict");
                put(".pkgdef", "text/plain");
                put(".pkgundef", "text/plain");
                put(".pko", "application/vnd.ms-pki.pko");
                put(".pls", "audio/scpls");
                put(".pma", "application/x-perfmon");
                put(".pmc", "application/x-perfmon");
                put(".pml", "application/x-perfmon");
                put(".pmr", "application/x-perfmon");
                put(".pmw", "application/x-perfmon");
                put(".png", "image/png");
                put(".pnm", "image/x-portable-anymap");
                put(".pnt", "image/x-macpaint");
                put(".pntg", "image/x-macpaint");
                put(".pnz", "image/png");
                put(".pot", "application/vnd.ms-powerpoint");
                put(".potm", "application/vnd.ms-powerpoint.template.macroEnabled.12");
                put(".potx", "application/vnd.openxmlformats-officedocument.presentationml.template");
                put(".ppa", "application/vnd.ms-powerpoint");
                put(".ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12");
                put(".ppm", "image/x-portable-pixmap");
                put(".pps", "application/vnd.ms-powerpoint");
                put(".ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12");
                put(".ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow");
                put(".ppt", "application/vnd.ms-powerpoint");
                put(".pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12");
                put(".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation");
                put(".prf", "application/pics-rules");
                put(".prm", "application/octet-stream");
                put(".prx", "application/octet-stream");
                put(".ps", "application/postscript");
                put(".psc1", "application/PowerShell");
                put(".psd", "application/octet-stream");
                put(".psess", "application/xml");
                put(".psm", "application/octet-stream");
                put(".psp", "application/octet-stream");
                put(".pub", "application/x-mspublisher");
                put(".pwz", "application/vnd.ms-powerpoint");
                put(".qht", "text/x-html-insertion");
                put(".qhtm", "text/x-html-insertion");
                put(".qt", "video/quicktime");
                put(".qti", "image/x-quicktime");
                put(".qtif", "image/x-quicktime");
                put(".qtl", "application/x-quicktimeplayer");
                put(".qxd", "application/octet-stream");
                put(".ra", "audio/x-pn-realaudio");
                put(".ram", "audio/x-pn-realaudio");
                put(".rar", "application/octet-stream");
                put(".ras", "image/x-cmu-raster");
                put(".rat", "application/rat-file");
                put(".rc", "text/plain");
                put(".rc2", "text/plain");
                put(".rct", "text/plain");
                put(".rdlc", "application/xml");
                put(".resx", "application/xml");
                put(".rf", "image/vnd.rn-realflash");
                put(".rgb", "image/x-rgb");
                put(".rgs", "text/plain");
                put(".rm", "application/vnd.rn-realmedia");
                put(".rmi", "audio/mid");
                put(".rmp", "application/vnd.rn-rn_music_package");
                put(".roff", "application/x-troff");
                put(".rpm", "audio/x-pn-realaudio-plugin");
                put(".rqy", "text/x-ms-rqy");
                put(".rtf", "application/rtf");
                put(".rtx", "text/richtext");
                put(".ruleset", "application/xml");
                put(".s", "text/plain");
                put(".safariextz", "application/x-safari-safariextz");
                put(".scd", "application/x-msschedule");
                put(".sct", "text/scriptlet");
                put(".sd2", "audio/x-sd2");
                put(".sdp", "application/sdp");
                put(".sea", "application/octet-stream");
                put(".searchConnector-ms", "application/windows-search-connector+xml");
                put(".setpay", "application/set-payment-initiation");
                put(".setreg", "application/set-registration-initiation");
                put(".settings", "application/xml");
                put(".sgimb", "application/x-sgimb");
                put(".sgml", "text/sgml");
                put(".sh", "application/x-sh");
                put(".shar", "application/x-shar");
                put(".shtml", "text/html");
                put(".sit", "application/x-stuffit");
                put(".sitemap", "application/xml");
                put(".skin", "application/xml");
                put(".sldm", "application/vnd.ms-powerpoint.slide.macroEnabled.12");
                put(".sldx", "application/vnd.openxmlformats-officedocument.presentationml.slide");
                put(".slk", "application/vnd.ms-excel");
                put(".sln", "text/plain");
                put(".slupkg-ms", "application/x-ms-license");
                put(".smd", "audio/x-smd");
                put(".smi", "application/octet-stream");
                put(".smx", "audio/x-smd");
                put(".smz", "audio/x-smd");
                put(".snd", "audio/basic");
                put(".snippet", "application/xml");
                put(".snp", "application/octet-stream");
                put(".sol", "text/plain");
                put(".sor", "text/plain");
                put(".spc", "application/x-pkcs7-certificates");
                put(".spl", "application/futuresplash");
                put(".src", "application/x-wais-source");
                put(".srf", "text/plain");
                put(".SSISDeploymentManifest", "text/xml");
                put(".ssm", "application/streamingmedia");
                put(".sst", "application/vnd.ms-pki.certstore");
                put(".stl", "application/vnd.ms-pki.stl");
                put(".sv4cpio", "application/x-sv4cpio");
                put(".sv4crc", "application/x-sv4crc");
                put(".svc", "application/xml");
                put(".swf", "application/x-shockwave-flash");
                put(".t", "application/x-troff");
                put(".tar", "application/x-tar");
                put(".tcl", "application/x-tcl");
                put(".testrunconfig", "application/xml");
                put(".testsettings", "application/xml");
                put(".tex", "application/x-tex");
                put(".texi", "application/x-texinfo");
                put(".texinfo", "application/x-texinfo");
                put(".tgz", "application/x-compressed");
                put(".thmx", "application/vnd.ms-officetheme");
                put(".thn", "application/octet-stream");
                put(".tif", "image/tiff");
                put(".tiff", "image/tiff");
                put(".tlh", "text/plain");
                put(".tli", "text/plain");
                put(".toc", "application/octet-stream");
                put(".tr", "application/x-troff");
                put(".trm", "application/x-msterminal");
                put(".trx", "application/xml");
                put(".ts", "video/vnd.dlna.mpeg-tts");
                put(".tsv", "text/tab-separated-values");
                put(".ttf", "application/octet-stream");
                put(".tts", "video/vnd.dlna.mpeg-tts");
                put(".txt", "text/plain");
                put(".u32", "application/octet-stream");
                put(".uls", "text/iuls");
                put(".user", "text/plain");
                put(".ustar", "application/x-ustar");
                put(".vb", "text/plain");
                put(".vbdproj", "text/plain");
                put(".vbk", "video/mpeg");
                put(".vbproj", "text/plain");
                put(".vbs", "text/vbscript");
                put(".vcf", "text/x-vcard");
                put(".vcproj", "Application/xml");
                put(".vcs", "text/plain");
                put(".vcxproj", "Application/xml");
                put(".vddproj", "text/plain");
                put(".vdp", "text/plain");
                put(".vdproj", "text/plain");
                put(".vdx", "application/vnd.ms-visio.viewer");
                put(".vml", "text/xml");
                put(".vscontent", "application/xml");
                put(".vsct", "text/xml");
                put(".vsd", "application/vnd.visio");
                put(".vsi", "application/ms-vsi");
                put(".vsix", "application/vsix");
                put(".vsixlangpack", "text/xml");
                put(".vsixmanifest", "text/xml");
                put(".vsmdi", "application/xml");
                put(".vspscc", "text/plain");
                put(".vss", "application/vnd.visio");
                put(".vsscc", "text/plain");
                put(".vssettings", "text/xml");
                put(".vssscc", "text/plain");
                put(".vst", "application/vnd.visio");
                put(".vstemplate", "text/xml");
                put(".vsto", "application/x-ms-vsto");
                put(".vsw", "application/vnd.visio");
                put(".vsx", "application/vnd.visio");
                put(".vtx", "application/vnd.visio");
                put(".wav", "audio/wav");
                put(".wave", "audio/wav");
                put(".wax", "audio/x-ms-wax");
                put(".wbk", "application/msword");
                put(".wbmp", "image/vnd.wap.wbmp");
                put(".wcm", "application/vnd.ms-works");
                put(".wdb", "application/vnd.ms-works");
                put(".wdp", "image/vnd.ms-photo");
                put(".webarchive", "application/x-safari-webarchive");
                put(".webtest", "application/xml");
                put(".wiq", "application/xml");
                put(".wiz", "application/msword");
                put(".wks", "application/vnd.ms-works");
                put(".WLMP", "application/wlmoviemaker");
                put(".wlpginstall", "application/x-wlpg-detect");
                put(".wlpginstall3", "application/x-wlpg3-detect");
                put(".wm", "video/x-ms-wm");
                put(".wma", "audio/x-ms-wma");
                put(".wmd", "application/x-ms-wmd");
                put(".wmf", "application/x-msmetafile");
                put(".wml", "text/vnd.wap.wml");
                put(".wmlc", "application/vnd.wap.wmlc");
                put(".wmls", "text/vnd.wap.wmlscript");
                put(".wmlsc", "application/vnd.wap.wmlscriptc");
                put(".wmp", "video/x-ms-wmp");
                put(".wmv", "video/x-ms-wmv");
                put(".wmx", "video/x-ms-wmx");
                put(".wmz", "application/x-ms-wmz");
                put(".wpl", "application/vnd.ms-wpl");
                put(".wps", "application/vnd.ms-works");
                put(".wri", "application/x-mswrite");
                put(".wrl", "x-world/x-vrml");
                put(".wrz", "x-world/x-vrml");
                put(".wsc", "text/scriptlet");
                put(".wsdl", "text/xml");
                put(".wvx", "video/x-ms-wvx");
                put(".x", "application/directx");
                put(".xaf", "x-world/x-vrml");
                put(".xaml", "application/xaml+xml");
                put(".xap", "application/x-silverlight-app");
                put(".xbap", "application/x-ms-xbap");
                put(".xbm", "image/x-xbitmap");
                put(".xdr", "text/plain");
                put(".xht", "application/xhtml+xml");
                put(".xhtml", "application/xhtml+xml");
                put(".xla", "application/vnd.ms-excel");
                put(".xlam", "application/vnd.ms-excel.addin.macroEnabled.12");
                put(".xlc", "application/vnd.ms-excel");
                put(".xld", "application/vnd.ms-excel");
                put(".xlk", "application/vnd.ms-excel");
                put(".xll", "application/vnd.ms-excel");
                put(".xlm", "application/vnd.ms-excel");
                put(".xls", "application/vnd.ms-excel");
                put(".xlsb", "application/vnd.ms-excel.sheet.binary.macroEnabled.12");
                put(".xlsm", "application/vnd.ms-excel.sheet.macroEnabled.12");
                put(".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
                put(".xlt", "application/vnd.ms-excel");
                put(".xltm", "application/vnd.ms-excel.template.macroEnabled.12");
                put(".xltx", "application/vnd.openxmlformats-officedocument.spreadsheetml.template");
                put(".xlw", "application/vnd.ms-excel");
                put(".xml", "text/xml");
                put(".xmta", "application/xml");
                put(".xof", "x-world/x-vrml");
                put(".XOML", "text/plain");
                put(".xpm", "image/x-xpixmap");
                put(".xps", "application/vnd.ms-xpsdocument");
                put(".xrm-ms", "text/xml");
                put(".xsc", "application/xml");
                put(".xsd", "text/xml");
                put(".xsf", "text/xml");
                put(".xsl", "text/xml");
                put(".xslt", "text/xml");
                put(".xsn", "application/octet-stream");
                put(".xss", "application/xml");
                put(".xtp", "application/octet-stream");
                put(".xwd", "image/x-xwindowdump");
                put(".z", "application/x-compress");
                put(".zip", "application/x-zip-compressed");
            }
        };
    }

    public static String getMimeType(String extension) {
        if (extension == null) {
            return null;
        }

        if (!extension.startsWith(".")) {
            extension = "." + extension.toLowerCase(Locale.getDefault());
        }

        String mime = mimeTypes.get(extension);

        return mime != null ? mime : "application/octet-stream";
    }
}

Como já publicado na resposta anterior, os tipos MIME mais comuns são configurados em um servidor da web. Por exemplo, no tomcat conf /, temos o web.xml com o seguinte MIME configurado:

   <mime-mapping>
      <extension>abs</extension>
      <mime-type>audio/x-mpeg</mime-type>
   </mime-mapping>
   <mime-mapping>
      <extension>ai</extension>
      <mime-type>application/postscript</mime-type>
   </mime-mapping>
   <mime-mapping>
      <extension>aif</extension>
      <mime-type>audio/x-aiff</mime-type>
   </mime-mapping>
...

Crie um ouvinte de inicialização que entre em ação quando o aplicativo Web for iniciado e analise esse arquivo XML, crie o ENUMS para você e vincule-o ao contexto do servlet para compartilhar a jusante.