Question

我正在尝试检查当前时间（小时和分钟）是否在特定时间之后或之前，如何在Kotlin中进行操作

Answer 1

您可以使用Calendar类：

import com.ericsson.otp.erlang.*;

import java.io.IOException;
import java.util.LinkedList;
import java.util.List;

public class Main {
    public static OtpErlangList StringListToErlangList(List<String> strs) {
        OtpErlangObject[] elems = new OtpErlangObject[strs.size()];

        int idx = 0;
        for (String str : strs) {
            elems[idx] = new OtpErlangString(str);
            idx++;
        }

        return new OtpErlangList(elems);
    }

    public static List<String> ErlangListToStringList(OtpErlangList estrs) {
        OtpErlangObject[] erlObjs = estrs.elements();
        List<String> strs = new LinkedList<String>();

        for (OtpErlangObject erlO : erlObjs) {
            strs.add(erlO.toString());
        }
        return strs;
    }

    public static void main(String[] args) throws IOException, InterruptedException {
        // Do some initial setup.
        OtpNode node = new OtpNode("alice", "secret");
        OtpMbox mbox = node.createMbox();
        mbox.registerName("alice");

        // Check that the remote node is actually online.
        if (node.ping("bob@127.0.0.1", 2000)) {
            System.out.println("remote is up");
        } else {
            System.out.println("remote is not up");
        }

        // Create the list of strings that needs to be sent to the other node.
        List<String> strs = new LinkedList<String>();
        strs.add("foo");
        strs.add("bar");
        OtpErlangList erlangStrs = StringListToErlangList(strs);

        // Create a tuple so the other node can reply to use.
        OtpErlangObject[] msg = new OtpErlangObject[2];
        msg[0] = mbox.self();
        msg[1] = erlangStrs;
        OtpErlangTuple tuple = new OtpErlangTuple(msg);

        // Send the tuple to the other node.
        mbox.send("echo", "bob@127.0.0.1", tuple);

        // Await the reply.
        while (true) {
            try {
                System.out.println("Waiting for response!");
                OtpErlangObject o = mbox.receive();

                if (o instanceof OtpErlangList) {
                    OtpErlangList erlList = (OtpErlangList) o;
                    List<String> receivedStrings = ErlangListToStringList(erlList);
                    for (String s : receivedStrings) {
                        System.out.println(s);
                    }
                }
                if (o instanceof OtpErlangTuple) {
                    OtpErlangTuple m = (OtpErlangTuple) o;
                    OtpErlangPid from = (OtpErlangPid) (m.elementAt(0));
                    OtpErlangList value = (OtpErlangList) m.elementAt(1);
                    List<String> receivedStrings = ErlangListToStringList(value);

                    for (String s : receivedStrings) {
                        System.out.println(s);
                    }
                }

            } catch (OtpErlangExit otpErlangExit) {
                otpErlangExit.printStackTrace();
            } catch (OtpErlangDecodeException e) {
                e.printStackTrace();
            }
        }
    }
}

Answer 2

如果您有LocalDateTime或类似名称，则可以提取MINUTE_OF_DAY（基本上是小时+分钟）来比较时间，而忽略其余时间，例如：

val now = LocalDateTime.now()
val dateToCompare : LocalDateTime = TODO()

val minutesOfDayNow = now.get(ChronoField.MINUTE_OF_DAY)
val minutesOfDayToCompare = dateToCompare.get(ChronoField.MINUTE_OF_DAY)

when {
  minutesOfDayNow == minutesOfDayToCompare -> // same hour and minute of day
  minutesOfDayNow > minutesOfDayToCompare -> // hours and minutes now are after the time to compare (only in regards to hours and minutes... not day/month/year or whatever)
  minutesOfDayNow < minutesOfDayToCompare -> // hours and minutes now are before the time to compare... same conditions apply
}

如果您有Date，则可能有兴趣将其转换为java.time类型的实例，例如：

fun Date.minutesOfDay() = toInstant().atZone(ZoneId.systemDefault()).get(ChronoField.MINUTE_OF_DAY)

val now = Date()
val dateToCompare : Date = TODO()

if (now.minutesOfDay() > dateToCompare.minutesOfDay()) // ...etc. pp.

最后，如果您想使用Calendar，请确保只比较您感兴趣的事物，例如小时和分钟，仅此而已，例如：

val now = Calendar.getInstance()
val nowInMinutes = now[Calendar.HOUR_OF_DAY] * 60 + now[Calendar.MINUTE]

val dateInMinutesToCompare = hours * 60 + minutes

when {
  nowInMinutes == dateInMinutesToCompare -> // equal
  nowInMinutes > dateInMinutesToCompare -> // now after given time
  else -> // now before given time
}

如何在Kotlin中检查当前时间是在特定时间之后还是之前

2 个答案: