java中二进制和流的相互转换

public static byte[] toByteArray(InputStream in) throws IOException {
ByteArrayOutputStream out=new ByteArrayOutputStream();
byte[] buffer=new byte[1024*4];
int n=0;
while ( (n=in.read(buffer)) !=-1) {
out.write(buffer,0,n);
}
return out.toByteArray();
}

public static byte[] toInputStream(byte[] b) throws IOException {
returnInputStream inputStream = new ByteArrayInputStream(b);
}