Java中File与byte[]的互转方式

public static byte[] getImageStream(String imageUrl, 
									HttpServletRequest request) {

	ServletContext application = request.getSession().getServletContext();
	String url = application.getRealPath("/")+imageUrl;
	byte[] buffer = null;
	File file = new File(url);
	FileInputStream fis;
	try {
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		fis = new FileInputStream(file);
	    byte[] b = new byte[1024];
        int n;
        while ((n = fis.read(b)) != -1) {
		     bos.write(b, 0, n);
		}
        fis.close();
        bos.close();
        buffer = bos.toByteArray();
        if(file.exists()) {
        	 file.delete();
        }
	} catch (FileNotFoundException e) {
		e.printStackTrace();
	}catch (IOException e) {
		e.printStackTrace();
	}
	return buffer;
}

public static void readBin2Image(byte[] byteArray, String targetPath) {
	InputStream in = new ByteArrayInputStream(byteArray);
    File file = new File(targetPath);
    String path = targetPath.substring(0, targetPath.lastIndexOf("/"));
    if (!file.exists()) {
        new File(path).mkdir();
    }
    FileOutputStream fos = null;
    try {
        fos = new FileOutputStream(file);
        int len = 0;
        byte[] buf = new byte[1024];
        while ((len = in.read(buf)) != -1) {
            fos.write(buf, 0, len);
        }
        fos.flush();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (null != fos) {
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

byte[] bytes = ...; 
StringBuilder binary = new StringBuilder(); 
for (byte b : bytes) { 
    int val = b; 
    for (int i = 0; i < 8; i++) { 
        binary.append((val &amp; 128) == 0 ? 0 : 1); 
        val <<= 1; 
    } 
} 
System.out.println(binary.toStri