generate uuid
===

public String createTransactionID() throws Exception{
    String uuid = UUID.randomUUID().toString().replaceAll("-", "").toUpperCase();
    return uuid.replaceAll("(\\w{8})(\\w{4})(\\w{4})(\\w{4})(\\w{12})", "$1-$2-$3-$4-$5");
}

## Ref.
[Generating unique id in android (UUID)](https://stackoverflow.com/a/40237325)

###### tags: `實作相關`