LEGACY('RAW', 'ANY<java.util.Map>')对应sql中数据类型改为：MAP<STRING,STRING>，仍然报错，异常：
org.apache.flink.table.api.TableException: A raw type backed by type
information has no serializable string representation. It needs to be
resolved into a proper raw type.
方便说下具体实现细节吗？-- Sent from: http://apache-flink.147419.n8.nabble.com/
