Java根据文件头判断文件类型

 //转自:http://blog.csdn.net/honwellhsueh/article/details/12913591
 public class FileType {

     private final static Map<String, String> FILE_TYPE_MAP = new HashMap<String, String>();

     private FileType(){}

     static{
         getAllFileType();  //初始化文件类型信息
     }

     private static void getAllFileType(){
         FILE_TYPE_MAP.put("ffd8ffe000104a464946", "jpg");
         FILE_TYPE_MAP.put("89504e470d0a1a0a0000", "png");
         FILE_TYPE_MAP.put("47494638396126026f01", "gif");
         FILE_TYPE_MAP.put("49492a00227105008037", "tif");
         FILE_TYPE_MAP.put("424d228c010000000000", "bmp"); // 16色位图(bmp)
         FILE_TYPE_MAP.put("424d8240090000000000", "bmp"); // 24位位图(bmp)
         FILE_TYPE_MAP.put("424d8e1b030000000000", "bmp"); // 256色位图(bmp)
         FILE_TYPE_MAP.put("41433130313500000000", "dwg");
         FILE_TYPE_MAP.put("3c21444f435459504520", "html");
         FILE_TYPE_MAP.put("3c21646f637479706520", "htm");
         FILE_TYPE_MAP.put("48544d4c207b0d0a0942", "css");
         FILE_TYPE_MAP.put("696b2e71623d696b2e71", "js");
         FILE_TYPE_MAP.put("7b5c727466315c616e73", "rtf");
         FILE_TYPE_MAP.put("38425053000100000000", "psd");
         FILE_TYPE_MAP.put("46726f6d3a203d3f6762", "eml");
         FILE_TYPE_MAP.put("d0cf11e0a1b11ae10000", "doc"); // MS Excel、Word、Msi
         FILE_TYPE_MAP.put("d0cf11e0a1b11ae10000", "vsd");
         FILE_TYPE_MAP.put("5374616E64617264204A", "mdb");
         FILE_TYPE_MAP.put("255044462d312e350d0a", "pdf");
         FILE_TYPE_MAP.put("2e524d46000000120001", "rmvb"); // rmvb、rm
         FILE_TYPE_MAP.put("464c5601050000000900", "flv"); // flv、f4v
         FILE_TYPE_MAP.put("00000020667479706d70", "mp4");
         FILE_TYPE_MAP.put("49443303000000002176", "mp3");
         FILE_TYPE_MAP.put("000001ba210001000180", "mpg");
         FILE_TYPE_MAP.put("3026b2758e66cf11a6d9", "wmv"); // wmv、asf
         FILE_TYPE_MAP.put("52494646e27807005741", "wav");
         FILE_TYPE_MAP.put("52494646d07d60074156", "avi");
         FILE_TYPE_MAP.put("4d546864000000060001", "mid");
         FILE_TYPE_MAP.put("504b0304140000000800", "zip");
         FILE_TYPE_MAP.put("526172211a0700cf9073", "rar");
         FILE_TYPE_MAP.put("235468697320636f6e66", "ini");
         FILE_TYPE_MAP.put("504b03040a0000000000", "jar");
         FILE_TYPE_MAP.put("4d5a9000030000000400", "exe");
         FILE_TYPE_MAP.put("3c25402070616765206c", "jsp");
         FILE_TYPE_MAP.put("4d616e69666573742d56", "mf");
         FILE_TYPE_MAP.put("3c3f786d6c2076657273", "xml");
         FILE_TYPE_MAP.put("494e5345525420494e54", "sql");
         FILE_TYPE_MAP.put("7061636b616765207765", "java");
         FILE_TYPE_MAP.put("406563686f206f66660d", "bat");
         FILE_TYPE_MAP.put("1f8b0800000000000000", "gz");
         FILE_TYPE_MAP.put("6c6f67346a2e726f6f74", "properties");
         FILE_TYPE_MAP.put("cafebabe0000002e0041", "class");
         FILE_TYPE_MAP.put("49545346030000006000", "chm");
         FILE_TYPE_MAP.put("04000000010000001300", "mxp");
         FILE_TYPE_MAP.put("504b0304140006000800", "docx");
         FILE_TYPE_MAP.put("d0cf11e0a1b11ae10000", "wps");// WPS(wps、et、dps)
         FILE_TYPE_MAP.put("6431303a637265617465", "torrent");
         FILE_TYPE_MAP.put("6D6F6F76", "mov");
         FILE_TYPE_MAP.put("FF575043", "wpd");
         FILE_TYPE_MAP.put("CFAD12FEC5FD746F", "dbx");
         FILE_TYPE_MAP.put("2142444E", "pst");
         FILE_TYPE_MAP.put("AC9EBD8F", "qdf");
         FILE_TYPE_MAP.put("E3828596", "pwl");
         FILE_TYPE_MAP.put("2E7261FD", "ram");
     }

     /**
      * 得到上传文件的文件头
      * @param src
      * @return
      */
     private static String bytesToHexString(byte[] src){
         StringBuilder stringBuilder = new StringBuilder();
         if(null==src || src.length <= 0){
             return null;
         }
         for(int i = 0; i < src.length; i++){
             int v = src[i] & 0xFF;
             String hv = Integer.toHexString(v);
             if(hv.length() < 2){
                 stringBuilder.append(0);
             }
             stringBuilder.append(hv);
         }
         return stringBuilder.toString();
     }

     /**
      * 获取文件类型
      * @param file
      * @return
      */
     public static String getFileType(File file){
         String res = null;
         try{
             @SuppressWarnings("resource")
             FileInputStream fis = new FileInputStream(file);
             byte[] b = new byte[10];
             fis.read(b, 0, b.length);
             String fileCode = bytesToHexString(b);

             Iterator<String> keyIter = FILE_TYPE_MAP.keySet().iterator();
             while(keyIter.hasNext()){
                 String key = keyIter.next();
                 if(key.toLowerCase().startsWith(fileCode.toLowerCase()) || fileCode.toLowerCase().startsWith(key.toLowerCase())){
                     res = FILE_TYPE_MAP.get(key);
                     break;
                 }
             }
         }catch(FileNotFoundException e){
             e.printStackTrace();
         }catch (IOException e){
             e.printStackTrace();
         }
         return res;
     }

 }