[QUESTION]自定义消息转换器fastjson1.x升级到2.x后不能用了

### Springboot 自定义消息转换器fastjson1.x升级到2.x后不能用了

以前使用fastjson1.x时WebMvcConfigurer 设置自定义消息转换器 configureMessageConverters，现在升级fastjson2.x后有些类找不到了，详见截屏：

```xml

com.alibaba.fastjson2
fastjson2
2.0.43


com.alibaba.fastjson2
fastjson2-extension
2.0.43


com.alibaba.fastjson2
fastjson2-extension-spring5
2.0.43


com.alibaba.fastjson2
fastjson2-extension-spring6
2.0.43

```

Start with the dependency list in the issue and the WebMvcConfigurer configureMessageConverters entry point, then compare the Spring integration APIs available in fastjson 2.0.43 with those used by fastjson 1.x. Done means identifying a supported custom message-converter configuration or documenting that the requested classes are unavailable; no repository file or test is named.

Written by the indexing model from the issue text.