access to DefaultFormBindingWriter.convertMapToString

[564155611]

i want to serialize request parameter with GBK url encoder, so i customize an Writer extends DefaultFormBindingWriter,but there is no way to override convertMapToString method for it is private.

[exabrial]

Can you post a link to the line of code? That seems like a reasonable request. I may not have time to implement, but I'd happily accept a PR