diff --git a/core-java-modules/core-java-datetime-conversion/src/main/java/com/baeldung/timestamptolong/TimestampToLong.java b/core-java-modules/core-java-datetime-conversion/src/main/java/com/baeldung/timestamptolong/TimestampToLong.java new file mode 100644 index 0000000000..2ebe30f4ff --- /dev/null +++ b/core-java-modules/core-java-datetime-conversion/src/main/java/com/baeldung/timestamptolong/TimestampToLong.java @@ -0,0 +1,32 @@ +package com.baeldung.timestamptolong; + +import java.sql.Timestamp; +import java.text.ParseException; +import java.text.SimpleDateFormat; +import java.time.Instant; +import java.time.LocalDateTime; +import java.time.ZoneId; +import java.util.Date; + +public class TimestampToLong { + public void usingSimpleDateFormat() throws ParseException { + SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); + String currentDateString = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()); + long actualTimestamp = sdf.parse(currentDateString).getTime(); + } + + public void usingInstantClass() { + Instant instant = Instant.now(); + long actualTimestamp = instant.toEpochMilli(); + } + + public void usingTimestamp() { + Timestamp timestamp = new Timestamp(System.currentTimeMillis()); + long actualTimestamp = timestamp.getTime(); + } + + public void usingJava8DateTime() { + LocalDateTime localDateTime = LocalDateTime.now(); + long actualTimestamp = localDateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli(); + } +} \ No newline at end of file diff --git a/core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/timestamptolong/TimestampToLongUnitTest.java b/core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/timestamptolong/TimestampToLongUnitTest.java new file mode 100644 index 0000000000..ede8f7792d --- /dev/null +++ b/core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/timestamptolong/TimestampToLongUnitTest.java @@ -0,0 +1,52 @@ +package com.baeldung.timestamptolong; + +import org.junit.Test; + +import java.sql.Timestamp; +import java.text.ParseException; +import java.text.SimpleDateFormat; +import java.time.Instant; +import java.time.LocalDateTime; +import java.time.ZoneId; +import java.util.Date; + +import static org.junit.Assert.assertTrue; + +public class TimestampToLongUnitTest { + + private static final long TOLERANCE = 1000; + + @Test + public void givenSimpleDateFormat_whenFormattingDate_thenTConvertToLong() throws ParseException { + SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); + + String currentDateString = sdf.format(new Date()); + long actualTimestamp = sdf.parse(currentDateString).getTime(); + + assertTrue(Math.abs(System.currentTimeMillis() - actualTimestamp) < TOLERANCE); + } + + @Test + public void givenInstantClass_whenGettingTimestamp_thenTConvertToLong() { + Instant instant = Instant.now(); + long actualTimestamp = instant.toEpochMilli(); + + assertTrue(Math.abs(System.currentTimeMillis() - actualTimestamp) < TOLERANCE); + } + + @Test + public void givenTimestamp_whenCreatingTimestamp_thenTConvertToLong() { + Timestamp timestamp = new Timestamp(System.currentTimeMillis()); + long actualTimestamp = timestamp.getTime(); + + assertTrue(Math.abs(System.currentTimeMillis() - actualTimestamp) < TOLERANCE); + } + + @Test + public void givenJava8DateTime_whenGettingTimestamp_thenTConvertToLong() { + LocalDateTime localDateTime = LocalDateTime.now(); + long actualTimestamp = localDateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli(); + + assertTrue(Math.abs(System.currentTimeMillis() - actualTimestamp) < TOLERANCE); + } +}