获取File文件类型

参考博客：
org.apache.tika
--java中利用tika判断文件类型
http://blog.sina.com.cn/s/blog_958a07d001014184.html
--va获取文件类型Mime Type的各种方法
http://dada89007.iteye.com/blog/1392606
--TIKA内容提取
http://www.yiibai.com/tika/tika_content_extraction.html
--常见文件的mime类型 可以根据mime+后缀名判断文件类型
http://blog.csdn.net/kuangshp128/article/details/75207984
http://www.w3school.com.cn/media/media_mimeref.asp
--使用apache.tika判断文件类型
https://blog.csdn.net/bedisdover/article/details/52706279

<dependency>
	    <groupId>org.apache.tika</groupId>
	    <artifactId>tika-core</artifactId>
	    <version>1.5</version>
	</dependency>

import org.apache.tika.metadata.HttpHeaders;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.metadata.TikaMetadataKeys;
import org.apache.tika.mime.MediaType;
import org.apache.tika.parser.AutoDetectParser;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
	/**
	 * 获取文件的mime类型
	 * @param multipartFile-来自spring-web-3.*.jar
	 * @return
	 */
   private String getFileMimeType(MultipartFile multipartFile) {
	    if (null == multipartFile) {
			logger.error("文件不存在。");
			return "";
		}
        AutoDetectParser parser = new AutoDetectParser();
        parser.setParsers(new HashMap<MediaType, Parser>());
        Metadata metadata = new Metadata();
        metadata.add(TikaMetadataKeys.RESOURCE_NAME_KEY, multipartFile.getOriginalFilename());
        InputStream stream=null;
        try {
            stream = multipartFile.getInputStream();
            parser.parse(stream, new DefaultHandler(), metadata, new ParseContext());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
        	//在finally语句块中关闭流
        	try {
				stream.close();
			} catch (IOException e) {
				logger.info("输入流InputStream关闭时异常");
				e.printStackTrace();
			}
		}
        return metadata.get(HttpHeaders.CONTENT_TYPE);
    }