long转换为字节数组
//long转换为字节数组
long n = 909090L;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(baos);
dos.writeLong(n);
byte[] buf = baos.toByteArray();
字节数组转换为long
byte[] buf = new byte[1024];
ByteArrayInputStream bais = new ByteArrayInputStream(buf);
DataInputStream dis = new DataInputStream();
long l = dis.readLong();