Explain spring boot custom HTTP message converter

In the process of building restful data services, we defined controllers and repositories and modified them with some annotations, but so far we have not performed object conversion -- converting Java entity objects into HTTP data output streams. The bottom layer of spring boot outputs Java entity classes to JSON format through httpmessageconverters and Jackson library. When multiple converters are available, the most suitable converter is selected according to the message object type and the required content type.

In the article httpmessageconverter of spring MVC source code analysis, there is a figure that can clearly show the location of the message converter.