java通过文件头内容判断文件类型

转自：http://space.itpub.net/23071790/viewspace-691870

/**

 * byte数组转换成16进制字符串

 * @param src

 * @return

 */

 public static String bytesToHexString(byte[] src){     

        StringBuilder stringBuilder = new StringBuilder();     

        if (src == null || 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();     

  }

 

/**

 * 根据文件流读取图片文件真实类型

 * @param is

 * @return

 */

 public static String getTypeByStream(FileInputStream is){

     byte[] b = new byte[4];  

     try {

   　　　　is.read(b, 0, b.length);

  　　} catch (IOException e) {

   　　　　e.printStackTrace();

  　　}

     String type = bytesToHexString(b).toUpperCase();

     if(type.contains("FFD8FF")){

         return "jpg";

     }else if(type.contains("89504E47")){

         return "png";

     }else if(type.contains("47494638")){

         return "gif";

     }else if(type.contains("49492A00")){

         return "tif";

     }else if(type.contains("424D")){

         return "bmp";

     }

        return type;

}



public static void main(String[] args) throws Exception {

//     String src = "D:/workspace//8129.jpg";

//     String src = "D:/workspace//temp/1.gif";

     String src = "D:/workspace//temp/2.bmp";

     FileInputStream is = new FileInputStream(src);  

//        byte[] b = new byte[4];  

//        is.read(b, 0, b.length);  

//        System.out.println(bytesToHexString(b));

       

        String type = getTypeByStream(is);

        System.out.println(type);

  /*

   * JPEG (jpg)，文件头：FFD8FF

PNG (png)，文件头：89504E47

GIF (gif)，文件头：47494638

TIFF (tif)，文件头：49492A00 

Windows Bitmap (bmp)，文件头：424D



   */

    }  

解析：

用文件头判断。直接读取文件的前几个字节。

常用文件的文件头如下：

JPEG (jpg)，文件头：FFD8FF

PNG (png)，文件头：89504E47

GIF (gif)，文件头：47494638

TIFF (tif)，文件头：49492A00 

Windows Bitmap (bmp)，文件头：424D

CAD (dwg)，文件头：41433130

Adobe Photoshop (psd)，文件头：38425053

Rich Text Format (rtf)，文件头：7B5C727466

XML (xml)，文件头：3C3F786D6C

HTML (html)，文件头：68746D6C3E

Email [thorough only] (eml)，文件头：44656C69766572792D646174653A

Outlook Express (dbx)，文件头：CFAD12FEC5FD746F 

Outlook (pst)，文件头：2142444E 

MS Word/Excel (xls.or.doc)，文件头：D0CF11E0

MS Access (mdb)，文件头：5374616E64617264204A

WordPerfect (wpd)，文件头：FF575043

Postscript. (eps.or.ps)，文件头：252150532D41646F6265

Adobe Acrobat (pdf)，文件头：255044462D312E

Quicken (qdf)，文件头：AC9EBD8F 

Windows Password (pwl)，文件头：E3828596 

ZIP Archive (zip)，文件头：504B0304 

RAR Archive (rar)，文件头：52617221 

Wave (wav)，文件头：57415645 

AVI (avi)，文件头：41564920 

Real Audio (ram)，文件头：2E7261FD 

Real Media (rm)，文件头：2E524D46 

MPEG (mpg)，文件头：000001BA 

MPEG (mpg)，文件头：000001B3

Quicktime (mov)，文件头：6D6F6F76 

Windows Media (asf)，文件头：3026B2758E66CF11 

MIDI (mid)，文件头：4D546864

GRAPHICS FILES

Adobe Photoshop File (.psd)

00000000  38 42 50 53 00 01 00 00  00 00 00 00 00 04 00 00  |8BPS............|

00000010  0b 71 00 00 10 dd 00 08  00 03 00 00 00 00 00 00  |.q...?..........|

00000020  6f c4 38 42 49 4d 04 04  00 00 00 00 00 07 1c 02  |o?8BIM..........|



JPEG image (.jpg)

00000000  ff d8 ff e0 00 10 4a 46  49 46 00 01 01 01 00 48  |????..JFIF.....H|

00000010  00 48 00 00 ff db 00 43  00 06 04 05 06 05 04 06  |.H..??.C........|

00000020  06 05 06 07 07 06 08 0a  10 0a 0a 09 09 0a 14 0e  |................|



PNG image (.png)

00000000  89 50 4e 47 0d 0a 1a 0a  00 00 00 0d 49 48 44 52  |.PNG........IHDR|

00000010  00 00 03 20 00 00 02 58  08 06 00 00 00 9a 76 82  |... ...X......v.|

00000020  70 00 00 0c d9 69 43 43  50 69 63 63 00 00 78 da  |p...?iCCPicc..x?|



GIF image (.gif)

00000000  47 49 46 38 39 61 10 00  10 00 b3 0d 00 3f 3f 3f  |GIF89a....?..???|

00000010  bf bf bf 2a 2a 2a 55 55  55 7f 7f 7f 15 15 15 40  |???***UUU......@|

00000020  40 40 60 60 60 c0 c0 c0  2f 2f 2f 90 90 90 ff ff  |@@```???///...??|



Adobe Illustrator File (.ai)

00000000  25 50 44 46 2d 31 2e 34  0d 25 e2 e3 cf d3 0d 0a  |%PDF-1.4.%????..|

00000010  31 20 30 20 6f 62 6a 3c  3c 2f 50 61 67 65 73 20  |1 0 obj<</Pages |

00000020  32 20 30 20 52 2f 54 79  70 65 2f 43 61 74 61 6c  |2 0 R/Type/Catal|

MUSIC FILES

MP3 Music Track (.mp3)

00000000  49 44 33 03 00 00 00 00  00 6f 54 49 54 32 00 00  |ID3......oTIT2..|

00000010  00 0e 00 00 00 54 68 65  20 4f 74 68 65 72 20 4d  |.....The Other M|

00000020  61 6e 54 52 43 4b 00 00  00 02 00 00 00 33 54 50  |anTRCK.......3TP|



WAV file (.wav)

00000000  52 49 46 46 62 b7 01 00  57 41 56 45 66 6d 74 20  |RIFFb?..WAVEfmt|

00000010  10 00 00 00 01 00 01 00  44 ac 00 00 88 58 01 00  |........D?...X..|

00000020  02 00 10 00 64 61 74 61  3e b7 01 00 57 01 bd 01  |....data>?..W.?.|



AIFF file (.aif)

00000000  46 4f 52 4d 00 2a ef cc  41 49 46 46 43 4f 4d 54  |FORM.*??AIFFCOMT|

00000010  00 00 01 c2 00 01 00 00  00 00 00 00 00 12 43 72  |...?..........Cr|

00000020  65 61 74 6f 72 3a 20 4c  6f 67 69 63 20 50 72 6f  |eator: Logic Pro|

TEXT FILES

Text file (often .txt, but not always)

00000000  48 69 20 65 76 65 72 79  6f 6e 65 2c 0a 0a 48 65  |Hi everyone,..He|

00000010  72 65 20 61 72 65 20 73  6f 6d 65 20 63 68 61 6e  |re are some chan|

00000020  67 65 73 20 74 68 61 74  20 77 69 6c 6c 20 68 61  |ges that will ha|



Microsoft Word/Office (.doc, .xls)

00000000d0 cf 11 e0 a1 b1 1a e100 00 00 00 00 00 00 00  |??.....?........|

00000010  00 00 00 00 00 00 00 00  3e 00 03 00 fe ff 09 00  |........>...??..|

00000020  06 00 00 00 00 00 00 00  00 00 00 00 01 00 00 00  |................|



Adobe PDF (.pdf) - Very similar to Adobe Illustrator and other Postscript. formats

00000000  25 50 44 46 2d 31 2e 34  0d 25 e2 e3 cf d3 0d 0a  |%PDF-1.4.%????..|

00000010  36 20 30 20 6f 62 6a 20  3c 3c 2f 4c 69 6e 65 61  |6 0 obj <</Linea|

00000020  72 69 7a 65 64 20 31 2f  4c 20 34 34 30 36 38 2f  |rized 1/L 44068/|

ANIMATION & VIDEO

Flash movie (.swf)

00000000  43 57 53 08 ac 43 00 00  78 9c ed 7a 77 58 93 c9  |CWS.?C..x.?zwX.?|

00000010  d6 f8 49 25 f4 80 94 50  0d 45 4a 00 e9 45 b0 04  |??I%?..P.EJ.?E?.|

00000020  44 44 45 e9 55 d0 80 44  01 11 10 11 01 75 0d bd  |DDE?U?.D.....u.?|



Quicktime Movie (.mov)

00000000  00 00 00 20 66 74 79 70  71 74 20 20 20 05 03 00  |... ftypqt   ...|

00000010  71 74 20 20 00 00 00 00  00 00 00 00 00 00 00 00  |qt............|

00000020  00 00 03 55 6d 6f 6f 76  00 00 00 6c 6d 76 68 64  |...Umoov...lmvhd|