将java.lang.double转换为org.joda.time.Instant

I have looked around a lot. I am very new to Java, and I am trying to cast a Double into an Instant. The use case is for the Google Dataflow Java SDK. The Double is a UNIX timestamp from a file I read using TextIO. When I System.out.println(row.get("timestamp")) I indeed get UNIX timestamps. When I do System.out.println(row.get("timestamp").getClass().getName()), then I get java.lang.double. what I have is as follows:

我环顾四周。我是Java的新手，我正在尝试将Double转换为Instant。该用例适用于Google Dataflow Java SDK。 Double是我使用TextIO读取的文件的UNIX时间戳。当我System.out.println（row.get（“timestamp”））我确实得到UNIX时间戳。当我做System.out.println（row.get（“timestamp”）。getClass（）。getName（）），然后我得到java.lang.double。我所拥有的如下：

static class ExtractTimestamp extends DoFn<TableRow, TableRow> {
    @Override
    public void processElement(ProcessContext c) {
        TableRow row = c.element();
        Instant timestamp = (Instant) row.get("timestamp");
        c.outputWithTimestamp(row, timestamp);
    }
}

The error I am getting is:

我得到的错误是：

java.lang.Double cannot be cast to org.joda.time.Instant

java.lang.Double无法强制转换为org.joda.time.Instant

The problem is that I want to cast the UNIX timestamps that are in double to Instants so I can pass it to outputWithTimestamp. I believe this should be a trivial problem, but I wasn't able to find the solution yet. Thank you.

问题是我想将双时的UNIX时间戳转换为Instants，因此我可以将它传递给outputWithTimestamp。我认为这应该是一个微不足道的问题，但我还没有找到解决方案。谢谢。

1 个解决方案

#1

You can't "cast" a Double to an Instant. You need to pass your timestamp as a constructor argument:

你无法将“双重”投射到瞬间。您需要将时间戳作为构造函数参数传递：

Instant timestamp = new Instant(((Number)row.getTimestamp("timestamp")).longValue());

This assumes the "timestamp" value is in milliseconds. If it's seconds, just multiply by 1000.

这假定“timestamp”值以毫秒为单位。如果它是秒，只需乘以1000。

#1