java library to find the mime type from file content [duplicate]

Question

I am searching for a java library which tells you the mime type by looking at the file content(byte array). I found this project using jmimemagic and it no longer supports newer file types (eg. MS word docx format) as it is inactive now (from 2006).

Answer 1

Maybe useful for someone, who needs the most used office formats as well (and does not use Apache Tika):

public class MimeTypeUtils {

    private static final Map<String, String> fileExtensionMap;

    static {
        fileExtensionMap = new HashMap<String, String>();
        // MS Office
        fileExtensionMap.put("doc", "application/msword");
        fileExtensionMap.put("dot", "application/msword");
        fileExtensionMap.put("docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document");
        fileExtensionMap.put("dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template");
        fileExtensionMap.put("docm", "application/vnd.ms-word.document.macroEnabled.12");
        fileExtensionMap.put("dotm", "application/vnd.ms-word.template.macroEnabled.12");
        fileExtensionMap.put("xls", "application/vnd.ms-excel");
        fileExtensionMap.put("xlt", "application/vnd.ms-excel");
        fileExtensionMap.put("xla", "application/vnd.ms-excel");
        fileExtensionMap.put("xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        fileExtensionMap.put("xltx", "application/vnd.openxmlformats-officedocument.spreadsheetml.template");
        fileExtensionMap.put("xlsm", "application/vnd.ms-excel.sheet.macroEnabled.12");
        fileExtensionMap.put("xltm", "application/vnd.ms-excel.template.macroEnabled.12");
        fileExtensionMap.put("xlam", "application/vnd.ms-excel.addin.macroEnabled.12");
        fileExtensionMap.put("xlsb", "application/vnd.ms-excel.sheet.binary.macroEnabled.12");
        fileExtensionMap.put("ppt", "application/vnd.ms-powerpoint");
        fileExtensionMap.put("pot", "application/vnd.ms-powerpoint");
        fileExtensionMap.put("pps", "application/vnd.ms-powerpoint");
        fileExtensionMap.put("ppa", "application/vnd.ms-powerpoint");
        fileExtensionMap.put("pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation");
        fileExtensionMap.put("potx", "application/vnd.openxmlformats-officedocument.presentationml.template");
        fileExtensionMap.put("ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow");
        fileExtensionMap.put("ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12");
        fileExtensionMap.put("pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12");
        fileExtensionMap.put("potm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12");
        fileExtensionMap.put("ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12");
        // Open Office
        fileExtensionMap.put("odt", "application/vnd.oasis.opendocument.text");
        fileExtensionMap.put("ott", "application/vnd.oasis.opendocument.text-template");
        fileExtensionMap.put("oth", "application/vnd.oasis.opendocument.text-web");
        fileExtensionMap.put("odm", "application/vnd.oasis.opendocument.text-master");
        fileExtensionMap.put("odg", "application/vnd.oasis.opendocument.graphics");
        fileExtensionMap.put("otg", "application/vnd.oasis.opendocument.graphics-template");
        fileExtensionMap.put("odp", "application/vnd.oasis.opendocument.presentation");
        fileExtensionMap.put("otp", "application/vnd.oasis.opendocument.presentation-template");
        fileExtensionMap.put("ods", "application/vnd.oasis.opendocument.spreadsheet");
        fileExtensionMap.put("ots", "application/vnd.oasis.opendocument.spreadsheet-template");
        fileExtensionMap.put("odc", "application/vnd.oasis.opendocument.chart");
        fileExtensionMap.put("odf", "application/vnd.oasis.opendocument.formula");
        fileExtensionMap.put("odb", "application/vnd.oasis.opendocument.database");
        fileExtensionMap.put("odi", "application/vnd.oasis.opendocument.image");
        fileExtensionMap.put("oxt", "application/vnd.openofficeorg.extension");
    }

    public static String getContentTypeByFileName(String fileName) {
        // 1. first use java's buildin utils
        FileNameMap mimeTypes = URLConnection.getFileNameMap();
        String contentType = mimeTypes.getContentTypeFor(fileName);
        // 2. nothing found -> lookup our in extension map to find types like ".doc" or ".docx"
        if (!StringUtils.hasText(contentType)) {
            String extension = FilenameUtils.getExtension(fileName);
            contentType = fileExtensionMap.get(extension);
        }
        return contentType;
    }
}