Android中Java根据文件头获取文件类型的方法

public class FileType {  public static final HashMap<String, String> mFileTypes = new HashMap<String, String>();  static {    //images    mFileTypes.put("FFD8FF", "jpg");    mFileTypes.put("89504E47", "png");    mFileTypes.put("47494638", "gif");    mFileTypes.put("49492A00", "tif");    mFileTypes.put("424D", "bmp");    //    mFileTypes.put("41433130", "dwg"); //CAD    mFileTypes.put("38425053", "psd");    mFileTypes.put("7B5C727466", "rtf"); //日记本    mFileTypes.put("3C3F786D6C", "xml");    mFileTypes.put("68746D6C3E", "html");    mFileTypes.put("44656C69766572792D646174653A", "eml"); //邮件    mFileTypes.put("D0CF11E0", "doc");    mFileTypes.put("5374616E64617264204A", "mdb");    mFileTypes.put("252150532D41646F6265", "ps");    mFileTypes.put("255044462D312E", "pdf");    mFileTypes.put("504B0304", "zip");    mFileTypes.put("52617221", "rar");    mFileTypes.put("57415645", "wav");    mFileTypes.put("41564920", "avi");    mFileTypes.put("2E524D46", "rm");    mFileTypes.put("000001BA", "mpg");    mFileTypes.put("000001B3", "mpg");    mFileTypes.put("6D6F6F76", "mov");    mFileTypes.put("3026B2758E66CF11", "asf");    mFileTypes.put("4D546864", "mid");    mFileTypes.put("1F8B08", "gz");    mFileTypes.put("", "");    mFileTypes.put("", "");  }  public static String getFileType(String filePath) {    return mFileTypes.get(getFileHeader(filePath));  }  //获取文件头信息  public static String getFileHeader(String filePath) {    FileInputStream is = null;    String value = null;    try {      is = new FileInputStream(filePath);      byte[] b = new byte[3];      is.read(b, 0, b.length);      value = bytesToHexString(b);    } catch (Exception e) {    } finally {      if(null != is) {        try {          is.close();        } catch (IOException e) {}      }    }    return value;  }  private static String bytesToHexString(byte[] src){     StringBuilder builder = new StringBuilder();     if (src == null || src.length <= 0) {       return null;     }     String hv;     for (int i = 0; i < src.length; i++) {       hv = Integer.toHexString(src[i] & 0xFF).toUpperCase();       if (hv.length() < 2) {         builder.append(0);       }       builder.append(hv);     }     return builder.toString();   }  public static void main(String[] args) throws Exception {    final String fileType = getFileType("D:/apache-tomcat-6.0.35.tar.gz");    System.out.println(fileType);  }}