Support microseconds in Duration conversions

Closes gh-13624

spring-boot-project/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -1263,6 +1263,7 @@ read timeout of 500ms can be specified in any of the following form: `500`, `PT0
 You can also use any of the supported unit. These are:
 
 * `ns` for nanoseconds
+* `us` for microseconds
 * `ms` for milliseconds
 * `s` for seconds
 * `m` for minutes

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/DurationStyle.java

@@ -180,6 +180,11 @@ public enum DurationStyle {
 		 */
 		NANOS(ChronoUnit.NANOS, "ns", Duration::toNanos),
 
+		/**
+		 * Microseconds.
+		 */
+		MICROS(ChronoUnit.MICROS, "us", (duration) -> duration.toMillis() * 1000L),
+
 		/**
 		 * Milliseconds.
 		 */

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/convert/DurationStyleTests.java

@@ -71,6 +71,18 @@ public class DurationStyleTests {
 				.isEqualTo(Duration.ofNanos(-10));
 	}
 
+	@Test
+	public void detectAndParseWhenSimpleMicrosShouldReturnDuration() {
+		assertThat(DurationStyle.detectAndParse("10us"))
+				.isEqualTo(Duration.ofNanos(10000));
+		assertThat(DurationStyle.detectAndParse("10US"))
+				.isEqualTo(Duration.ofNanos(10000));
+		assertThat(DurationStyle.detectAndParse("+10us"))
+				.isEqualTo(Duration.ofNanos(10000));
+		assertThat(DurationStyle.detectAndParse("-10us"))
+				.isEqualTo(Duration.ofNanos(-10000));
+	}
+
 	@Test
 	public void detectAndParseWhenSimpleMillisShouldReturnDuration() {
 		assertThat(DurationStyle.detectAndParse("10ms")).isEqualTo(Duration.ofMillis(10));

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/convert/StringToDurationConverterTests.java

@@ -70,6 +70,14 @@ public class StringToDurationConverterTests {
 		assertThat(convert("-10ns")).isEqualTo(Duration.ofNanos(-10));
 	}
 
+	@Test
+	public void convertWhenSimpleMicrosShouldReturnDuration() {
+		assertThat(convert("10us")).isEqualTo(Duration.ofNanos(10000));
+		assertThat(convert("10US")).isEqualTo(Duration.ofNanos(10000));
+		assertThat(convert("+10us")).isEqualTo(Duration.ofNanos(10000));
+		assertThat(convert("-10us")).isEqualTo(Duration.ofNanos(-10000));
+	}
+
 	@Test
 	public void convertWhenSimpleMillisShouldReturnDuration() {
 		assertThat(convert("10ms")).isEqualTo(Duration.ofMillis(10));