Flink CDC里为什么我运行好了demo没有数据出来？

Flink CDC里为什么我运行好了demo没有数据出来？public class MySqlCDCSourceExample {
public static void main(String[] args) throws Exception {
MySqlSource mySqlSource = MySqlSource.builder()
.hostname("localhost")
.port(3306)
.databaseList("demo") // set captured database
.tableList("demo.answer_paper") // set captured table
.username("root")
.password("Hadoop.123456")
.deserializer(new JsonDebeziumDeserializationSchema()) // converts SourceRecord to JSON String
.build();

    StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

    // enable checkpoint
    env.enableCheckpointing(3000);

    env
            .fromSource(mySqlSource, WatermarkStrategy.noWatermarks(), "MySQL Source")
            // set 4 parallel source tasks
            .setParallelism(4)
            .print().setParallelism(1); // use parallelism 1 for sink to keep message ordering

    env.execute("Print MySQL Snapshot + Binlog");
}

}