How to determine the type of the uploaded file

Determine with the file header. Directly read the first few bytes of the file. Common File Header: JPEG (JPG), file header: ffd8ff PNG (PNG), file header: 89504e47 GIF (GIF), file header: 47494638 tiff (TIF), file header: 4910000a00 Windows Bitmap (BMP), file header: Drawing d cad (DWG), file header: 41433130 Adobe Photoshop (PSD), file header: 38425053 Rich Text Format (RTF), file header: 7b5c727466 XML (XML), file header: 3c3f786d6c HTML (HTML), file header: 68746d6c3e email [thorough only] (EML), file header: Outlook Express (DBX), file header: export outlook (PST), file header: 2142444e MS word/Excel (xls.or.doc), file header: d0cf11e0 MS access (MDB), file header: Export Wordperfect (WPD), file header: ff575043 postscript (EPS. or. PS), file header: Adobe Acrobat (PDF), file header: 255044462d312e quicken (qdf), file header: ac9ebd8f Windows Password (pwl), file header: e3828596 ZIP Archive (ZIP), file header: 504b0304 RAR Archive (RAR), file header: 52617221 wave (WAV), file header: 57415645 AVI (AVI), file header: 41564920 Real Audio (RAM), file header: 2e00001fd Real Media (RM), file header: 2e524d46 MPEG (MPG), file header: 000001ba MPEG (MPG), file header: 000001b3 QuickTime (mov), file header: 6d6f6f76 Windows Media (ASF ), file Header: 3026b2758e66cf11 Midi (MID), file header: 4d546864

 

package org.test;import java.io.FileInputStream;public class Test {    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();        }        /**     * @param args     */    public static void main(String[] args) throws Exception {        FileInputStream is = new FileInputStream("D:\\face.jpg");        byte[] b = new byte[3];        is.read(b, 0, b.length);        System.out.println(bytesToHexString(b));    }}