Support for customized ProviderSqlSource.

[abel533]

Enhances the functionality by customizing the ProviderSqlSource.

synchronized with latest code

see also #1120, #1111

[harawata]

Hi @abel533 ,

Thank you for the PRs and sorry for my lack of response.
You wrote...

This feature is very useful and it is easy for developers to create the underlying framework.

So, this is another attempt to auto-generate SQLs, I presume.
I've been thinking about this request for a while, but building a framework that generates XML string does not seem to be the right approach to me.
And even if this PR is merged, how do you plan to auto-generate result maps?

[abel533]

The simplest way is to use column aliases, the other way is getting the MappedStatement of the current interface method through Configuration can also override the result map.

There is a common Mapper that is commonly used in China. This implementation is to modify the MappedStatement during initialization. Although this method works well, it is more complicated to understand. With this pr, it can be implemented in a more compact way and can be easily extended and understand.

If this PR can be merged, I will provide a framework for reference as soon as possible. It is more convenient to use this function than MBG(because it is dynamically generated at runtime).

[abel533]

@harawata Please resolve this PR before the 3.5.0 release.

[harawata]

Hi @abel533 ,
As I wrote, this does not seem to be the right approach to me.
I keep it open because other devs might have a different opinion.