yangbongsoo's blog

The meaning of the Optional form (Monad)

May 15, 20224 min read

I don't deal with the exact concept of Monad, but try to look at the form used by Java Optional from a Monad application perspective. Monad has a...

Java Date format compatible

May 8, 20222 min read

If we make java.util.Date object, basically log format is below. Sun May 08 18:03:23 KST 2022 Our team has an old system that is more than 10 years...

SLF4J Error Log Format

Apr 30, 20221 min read

Variable s has string value. If I put that variable in Integer.valueOf method, I must encounter NumberFormatException. But It's not important. I just...

Beware of using spring WebClient(Episode7)

Apr 24, 20221 min read

This episode story is simple. If we receive response that is list type, we can use flatMapIterable operator(finally return type is Flux). Sometimes, I...

Beware of using spring WebClient(Episode6)

Apr 17, 20222 min read

Let's imagine we received the WebClient response data and then binding to ResponseDto. Message value in ResponseDto can be null. public class...

Beware of using spring WebClient(Episode5)

Apr 10, 20223 min read

Metric We have to know that It is different between WebClient level metric and reactor.netty level metric which is implementation of WebClient. At...