您的位置:首页 > 编程语言 > Java开发

java通过文件头内容判断文件类型

2012-03-24 01:42 489 查看
转载自: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

*/

}

==================================

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





内容来自用户分享和网络整理,不保证内容的准确性,如有侵权内容,可联系管理员处理 点击这里给我发消息
标签: