异常信息：
com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.apache.ibatis.executor.loader.javassist.JavassistProxyFactoryKaTeX parse error: Expected group after '_' at position 235: ….glc.bean.Route_̲$_jvst8ad_0[“handler”])
解决方法
关闭全局懒加载
<setting name
="lazyLoadingEnabled" value
="false"/>
或关闭该查询的懒加载 fetchType=“eager”
<collection
... fetchType
="eager">
</collection
>
返回的类加上注解
@JsonIgnoreProperties(value = { “handler” })
3. json转换器属性SerializationFeature.FAIL_ON_EMPTY_BEANS为false 详情：https://blog.csdn.net/justinytsoft/article/details/53575236
