可以创建一个自定义的`AssignerWithPeriodicWatermarks`实现类

在Flink CDC中，可以使用AssignerWithPeriodicWatermarks接口来处理时间戳的转换。具体来说，可以创建一个自定义的AssignerWithPeriodicWatermarks实现类，将timestamp(3)类型乘以1000，然后将其转换为事件时间水印。

以下是一个示例代码：

import org.apache.flink.streaming.api.functions.timestamps.BoundedOutOfOrdernessTimestampExtractor;
import org.apache.flink.streaming.api.watermark.Watermark;
import org.apache.flink.streaming.api.windowing.time.Time;

public class CustomTimestampExtractor implements AssignerWithPeriodicWatermarks<Event> {
   
    private long maxTs = Long.MIN_VALUE;
    private final long delayBetweenMaxTimestamps = 1000L; // delay between max timestamps to be considered as watermark

    @Override
    public long extractTimestamp(Event element, long previousElementTimestamp) {
   
        long timestamp = element.getTimestamp() * 1000; // multiply by 1000
        maxTs = Math.max(maxTs, timestamp);
        return timestamp;
    }

    @Override
    public Watermark getCurrentWatermark() {
   
        return new Watermark(maxTs - delayBetweenMaxTimestamps);
    }

    @Override
    public long extractTimestamp(Event element, long previousElementTimestamp, long previousElementMaxTimestamp) {
   
        // same logic as above
    }
}

在上面的代码中，extractTimestamp方法用于提取事件的时间戳并将其乘以1000。getCurrentWatermark方法返回一个基于最大时间戳和延迟之间的最大时间戳的水印。