import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
public void testFileExtension() throws IOException{
	new FileTypeDetector() {
		@Override
		public String probeContentType(Path file) throws IOException {
			String type;				
			// Basic check on the type using the filename
			if (file.toString().lastIndexOf('.') != -1) {
				type = file.toString().substring( file.toString().lastIndexOf('.') );
			} else {
				type = null;
			}
			return type;				
		}			
	};		
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
private static FileTypeDetector createDefaultFileTypeDetector() {
    return AccessController
        .doPrivileged(new PrivilegedAction<FileTypeDetector>() {
            @Override public FileTypeDetector run() {
                return sun.nio.fs.DefaultFileTypeDetector.create();
        }});
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
private static List<FileTypeDetector> loadInstalledDetectors() {
    return AccessController
        .doPrivileged(new PrivilegedAction<List<FileTypeDetector>>() {
            @Override public List<FileTypeDetector> run() {
                List<FileTypeDetector> list = new ArrayList<>();
                ServiceLoader<FileTypeDetector> loader = ServiceLoader
                    .load(FileTypeDetector.class, ClassLoader.getSystemClassLoader());
                for (FileTypeDetector detector: loader) {
                    list.add(detector);
                }
                return list;
        }});
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
/**
 * Returns a {@code FileTypeDetector} for this platform.
 */
FileTypeDetector getFileTypeDetector() {
    return new AbstractFileTypeDetector() {
        @Override
        public String implProbeContentType(Path file) {
            return null;
        }
    };
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
/**
 * Returns a {@code FileTypeDetector} that chains the given array of file
 * type detectors. When the {@code implProbeContentType} method is invoked
 * then each of the detectors is invoked in turn, the result from the
 * first to detect the file type is returned.
 */
final FileTypeDetector chain(final AbstractFileTypeDetector... detectors) {
    return new AbstractFileTypeDetector() {
        @Override
        protected String implProbeContentType(Path file) throws IOException {
            for (AbstractFileTypeDetector detector : detectors) {
                String result = detector.implProbeContentType(file);
                if (result != null && !result.isEmpty()) {
                    return result;
                }
            }
            return null;
        }
    };
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
@Override
FileTypeDetector getFileTypeDetector() {
    Path userMimeTypes = Paths.get(AccessController.doPrivileged(
        new GetPropertyAction("user.home")), ".mime.types");
    Path etcMimeTypes = Paths.get("/etc/mime.types");

    return chain(new GnomeFileTypeDetector(),
                 new MimeTypesFileTypeDetector(userMimeTypes),
                 new MimeTypesFileTypeDetector(etcMimeTypes),
                 new MagicFileTypeDetector());
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
@Override
FileTypeDetector getFileTypeDetector() {
    Path userMimeTypes = Paths.get(AccessController.doPrivileged(
        new GetPropertyAction("user.home")), ".mime.types");
    Path etcMimeTypes = Paths.get("/etc/mime.types");

    return chain(new GnomeFileTypeDetector(),
                 new MimeTypesFileTypeDetector(userMimeTypes),
                 new MimeTypesFileTypeDetector(etcMimeTypes));
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
public static FileTypeDetector create()
{
    return new AbstractFileTypeDetector() {
        public String implProbeContentType(Path obj) throws IOException {
            return null;
        }
    };
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
private static FileTypeDetector createDefaultFileTypeDetector() {
    return AccessController
        .doPrivileged(new PrivilegedAction<>() {
            @Override public FileTypeDetector run() {
                return sun.nio.fs.DefaultFileTypeDetector.create();
        }});
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
private static List<FileTypeDetector> loadInstalledDetectors() {
    return AccessController
        .doPrivileged(new PrivilegedAction<>() {
            @Override public List<FileTypeDetector> run() {
                List<FileTypeDetector> list = new ArrayList<>();
                ServiceLoader<FileTypeDetector> loader = ServiceLoader
                    .load(FileTypeDetector.class, ClassLoader.getSystemClassLoader());
                for (FileTypeDetector detector: loader) {
                    list.add(detector);
                }
                return list;
        }});
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
@Override
FileTypeDetector getFileTypeDetector() {
    String userHome = GetPropertyAction.privilegedGetProperty("user.home");
    Path userMimeTypes = Paths.get(userHome, ".mime.types");
    Path etcMimeTypes = Paths.get("/etc/mime.types");

    return chain(new MimeTypesFileTypeDetector(userMimeTypes),
                 new MimeTypesFileTypeDetector(etcMimeTypes));
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
@Override
FileTypeDetector getFileTypeDetector() {
    Path userMimeTypes = Paths.get(GetPropertyAction
            .privilegedGetProperty("user.home"), ".mime.types");

    return chain(new MimeTypesFileTypeDetector(userMimeTypes),
                 new UTIFileTypeDetector());
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
@Override
FileTypeDetector getFileTypeDetector() {
    Path userMimeTypes = Paths.get(
        GetPropertyAction.privilegedGetProperty("user.home"), ".mime.types");
    Path etcMimeTypes = Paths.get("/etc/mime.types");

    return chain(new MimeTypesFileTypeDetector(userMimeTypes),
                 new MimeTypesFileTypeDetector(etcMimeTypes));
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
@Override
FileTypeDetector getFileTypeDetector() {
    String userHome = GetPropertyAction.privilegedGetProperty("user.home");
    Path userMimeTypes = Paths.get(userHome, ".mime.types");
    Path etcMimeTypes = Paths.get("/etc/mime.types");

    return chain(new GioFileTypeDetector(),
                 new MimeTypesFileTypeDetector(userMimeTypes),
                 new MimeTypesFileTypeDetector(etcMimeTypes),
                 new MagicFileTypeDetector());
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
@Override
FileTypeDetector getFileTypeDetector() {
    Path userMimeTypes = Paths.get(
        GetPropertyAction.privilegedGetProperty("user.home"), ".mime.types");
    Path etcMimeTypes = Paths.get("/etc/mime.types");

    return chain(new GioFileTypeDetector(),
                 new MimeTypesFileTypeDetector(userMimeTypes),
                 new MimeTypesFileTypeDetector(etcMimeTypes));
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
private static List<FileTypeDetector> getInstalledDetectors() {
    ArrayList<FileTypeDetector> detectors = new ArrayList<>();
    ServiceLoader<FileTypeDetector> serviceLoader = ServiceLoader.load(FileTypeDetector.class);
    for (FileTypeDetector fileTypeDetector : serviceLoader) {
        LOGGER.info("Adding content type detector: {}", fileTypeDetector.getClass());
        detectors.add(fileTypeDetector);
    }
    return detectors;
}
 

import java.nio.file.spi.FileTypeDetector; //导入依赖的package包/类
/**
 * Probes the content type of a file.
 * 
 * Same as {@link Files#probeContentType(Path)} but uses context class loader.
 * @param path
 *              the path to the file to probe
 * @return The content type of the file, or null if the content type cannot be determined
 * @throws IOException if an I/O error occurs
 */
public static String probeContentType(Path path) throws IOException {
    LOGGER.debug("Probing content type: {}", path);
    for (FileTypeDetector fileTypeDetector : fileTypeDetectors) {
        LOGGER.debug("Using type detector: {}", fileTypeDetector.getClass());
        String contentType = fileTypeDetector.probeContentType(path);
        if (contentType != null) {
            LOGGER.debug("Content type: {}", contentType);
            return contentType;
        }
    }
    return Files.probeContentType(path);
}