Java 读取文件 文件头字节码信息，判断文件类型

不同文件对应的文件头信息：
(“FFD8FFE0”, “jpg”);
(“89504E47”, “png”);
(“47494638”, “gif”);
(“49492A00”, “tif”);
(“424D”, “bmp”); //
(“41433130”, “dwg”); // CAD
(“38425053”, “psd”);
(“7B5C727466”, “rtf”); // 日记本
(“3C3F786D6C”, “xml”);
(“68746D6C3E”, “html”);
(“44656C69766572792D646174653A”, “eml”); // 邮件
(“D0CF11E0”, “doc”); // word or xls
(“5374616E64617264204A”, “mdb”);
(“252150532D41646F6265”, “ps”);
(“255044462D312E”, “pdf”);
(“504B0304”, “docx”); //word or xlsx
(“52617221”, “rar”);
(“57415645”, “wav”);
(“41564920”, “avi”);
(“2E524D46”, “rm”);
(“000001BA”, “mpg”);
(“000001B3”, “mpg”);
(“6D6F6F76”, “mov”);
(“3026B2758E66CF11”, “asf”);
(“4D546864”, “mid”);
(“1F8B08”, “gz”);
(“4D5A9000”, “exe/dll”);
(“75736167”, “txt”);

java 代码：
		import java.io.ByteArrayOutputStream;
		import java.io.File;
		import java.io.FileInputStream;
		import java.io.FileNotFoundException;
		import java.io.IOException;
		import java.util.Arrays;
 /**   
 * @ClassName:  GetFileType   
 */
public class GetFileType {
	/** 
     * 获得指定文件的byte数组 
     */  
    public static byte[] getBytes(String filePath){  
        byte[] buffer = null;  
        try {  
            File file = new File(filePath);  
            FileInputStream fis = new FileInputStream(file);  
            ByteArrayOutputStream bos = new ByteArrayOutputStream(1000);  
            byte[] b = new byte[(int)file.length()];  
            int n;  
            while ((n = fis.read(b)) != -1) {  
                bos.write(b, 0, n);  
            }  
            fis.close();  
            bos.close();  
            buffer = bos.toByteArray();  
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
        return buffer;  
    }
    
    /**
     * 将要读取文件头信息的文件的byte数组转换成string类型表示
     * @param src	要读取文件头信息的文件的byte数组
     * @return 文件头信息
     */
    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++) {
            // 以十六进制（基数 16）无符号整数形式返回一个整数参数的字符串表示形式，并转换为大写
            hv = Integer.toHexString(src[i] & 0xFF).toUpperCase();
            if (hv.length() < 2) {
                builder.append(0);
            }
            builder.append(hv);
        }

        return builder.toString();
    }
    
    /**
     * @return boolean
     */
    public static boolean fileTypes(byte[] bytes){
        //文件的文件头信息
        byte[] b = new byte[4];
        
        for (int i=0; i

文章转载自：https://www.cnblogs.com/onop/p/10219994.html