Flink解析kafka Protobuf格式数据 map函数处理时报错

Question

问题描述：
Flink解析kafka Protobuf格式数据 map函数处理时报错

报错信息

   SingleOutputStreamOperator<MessageDB.Record> map1
                = kafka_source.map(t -> MessageDB.Record.parseFrom((byte[]) t.value()));

        SingleOutputStreamOperator<Object> objectSingleOutputStreamOperator = map1.flatMap(new FlatMapFunction<MessageDB.Record, Object>() {

            @Override
            public void flatMap(MessageDB.Record record, Collector<Object> collector) throws Exception {
                collector.collect(record.getTableName());
            }
        });