Bael 7989 storing date time in postgres (eugenp#18006)

* BAEL-7989 Storing date and time in PostgreSQL

* BAEL-7989 Fix format

* BAEL-7989 Update pom to fix build

* BAEL-7989 Update UCT to UTC

* BAEL-7989 Update integration test

* BAEL-7989 Update test method names

---------

Co-authored-by: michaelk <[email protected]>

persistence-modules/spring-boot-postgresql/pom.xml

@@ -41,6 +41,9 @@
 			<plugin>
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-maven-plugin</artifactId>
+				<configuration>
+					<mainClass>com.baeldung.boot.Application</mainClass>
+				</configuration>
 				<executions>
 					<execution>
 						<goals>

persistence-modules/spring-boot-postgresql/src/main/java/com/baeldung/postgres/datetime/Application.java

@@ -0,0 +1,12 @@
+package com.baeldung.postgres.datetime;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+}

persistence-modules/spring-boot-postgresql/src/main/java/com/baeldung/postgres/datetime/DateTimeValueRepository.java

@@ -0,0 +1,10 @@
+package com.baeldung.postgres.datetime;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.io.Serializable;
+
+@Repository
+public interface DateTimeValueRepository extends JpaRepository<DateTimeValues, Serializable> {
+}

persistence-modules/spring-boot-postgresql/src/main/java/com/baeldung/postgres/datetime/DateTimeValues.java

@@ -0,0 +1,53 @@
+package com.baeldung.postgres.datetime;
+
+import jakarta.persistence.*;
+
+import java.time.*;
+import java.util.Date;
+
+@Entity
+public class DateTimeValues {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Integer id;
+
+    private Date date;
+    private LocalDate localDate;
+    private LocalDateTime localDateTime;
+    private Instant instant;
+    private ZonedDateTime zonedDateTime;
+    private LocalTime localTime;
+    private OffsetDateTime offsetDateTime;
+    private java.sql.Date sqlDate;
+
+    @Column(columnDefinition = "date")
+    private Instant instantAsDate;
+
+    private String zoneId;
+
+    public DateTimeValues() {
+        Clock clock = Clock.fixed(Instant.parse("2024-08-01T14:15:00Z"), ZoneId.of("UTC"));
+
+        this.date = new Date(clock.millis());
+        this.localDate = LocalDate.now(clock);
+        this.localDateTime = LocalDateTime.now(clock);
+        this.zonedDateTime = ZonedDateTime.now(clock);
+        this.instant = Instant.now(clock);
+        this.localTime = LocalTime.now(clock);
+        this.offsetDateTime = OffsetDateTime.now(clock);
+        this.instantAsDate = Instant.now(clock);
+        this.sqlDate = java.sql.Date.valueOf(LocalDate.now(clock));
+
+        this.zoneId = ZoneId.systemDefault().getId();
+    }
+
+    public Integer getId() {
+        return id;
+    }
+
+    public Instant getInstantAsDate() {
+        return instantAsDate;
+    }
+
+}

persistence-modules/spring-boot-postgresql/src/test/java/com/baeldung/postgres/datetime/DateTimeIntegrationTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.postgres.datetime;
+
+import org.junit.Test;
+import org.junit.jupiter.api.Assertions;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.time.temporal.ChronoUnit;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = {Application.class})
+public class DateTimeIntegrationTest {
+
+    @Autowired
+    private DateTimeValueRepository dateTimeValueRepository;
+
+    @Test
+    public void givenJavaDateTimesValues_whenPersisted_thenAllValuesAreStored() {
+
+        // Given
+        DateTimeValues dateTimeValues = new DateTimeValues();
+
+        // When
+        dateTimeValues = dateTimeValueRepository.save(dateTimeValues);
+        DateTimeValues persisted = dateTimeValueRepository.findById(dateTimeValues.getId()).get();
+
+        // Then
+        assertNotNull(persisted);
+    }
+
+    @Test
+    public void givenJavaInstant_whenPersistedAsSqlDate_thenRetrievedWithoutTime() {
+        DateTimeValues dateTimeValues = new DateTimeValues();
+        DateTimeValues persisted = dateTimeValueRepository.save(dateTimeValues);
+        DateTimeValues fromDatabase = dateTimeValueRepository.findById(persisted.getId()).get();
+
+        Assertions.assertNotEquals(dateTimeValues.getInstantAsDate(), fromDatabase.getInstantAsDate());
+        Assertions.assertEquals(dateTimeValues.getInstantAsDate().truncatedTo(ChronoUnit.DAYS), fromDatabase.getInstantAsDate());
+    }
+}