Implemented a LocalDateTime-to-Date converter

diff --git a/src/main/java/de/juplo/jpa/converters/LocalDateTimeConverter.java b/src/main/java/de/juplo/jpa/converters/LocalDateTimeConverter.java
new file mode 100644 (file)
index 0000000..0e5251d
--- /dev/null
+++ b/src/main/java/de/juplo/jpa/converters/LocalDateTimeConverter.java
@@ -0,0 +1,36 @@
+package de.juplo.jpa.converters;
+
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneOffset;
+import java.util.Date;
+import javax.persistence.AttributeConverter;
+import javax.persistence.Converter;
+
+
+/**
+ * Converts a {@link LocalDateTime} to a {@link Date}, by converting it into
+ * an {@Instant} for the GMT-timezone and then convering that {@link Instant}
+ * into a {@link Date} as suggested in the official Java 8 Time tutorial.
+ * <p>
+ * The {@link Date} can then be persisted as
+ * {@link java.persistene.TemporalType.TIMESTAMP} with the help of the
+ * {@link java.persist.Tmporal}-annotation.
+ * @see https://docs.oracle.com/javase/tutorial/datetime/iso/legacy.html
+ * @author Kai Moritz
+ */
+@Converter(autoApply = true)
+public class LocalDateTimeConverter implements AttributeConverter<LocalDateTime, Date>
+{
+  @Override
+  public Date convertToDatabaseColumn(LocalDateTime ldt)
+  {
+    return Date.from(ldt.toInstant(ZoneOffset.UTC));
+  }
+
+  @Override
+  public LocalDateTime convertToEntityAttribute(Date date)
+  {
+    return LocalDateTime.from(date.toInstant());
+  }
+}