Polish "Make sure exception tag values are not empty in web metrics"

Closes gh-13187

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/reactive/server/WebFluxTags.java

@@ -19,6 +19,7 @@ package org.springframework.boot.actuate.metrics.web.reactive.server;
 import io.micrometer.core.instrument.Tag;
 
 import org.springframework.http.HttpStatus;
+import org.springframework.util.StringUtils;
 import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.util.pattern.PathPattern;
@@ -110,7 +111,8 @@ public final class WebFluxTags {
 	public static Tag exception(Throwable exception) {
 		if (exception != null) {
 			String simpleName = exception.getClass().getSimpleName();
-			return Tag.of("exception", simpleName.isEmpty() ? exception.getClass().getName() : simpleName);
+			return Tag.of("exception", StringUtils.hasText(simpleName) ? simpleName
+					: exception.getClass().getName());
 		}
 		return EXCEPTION_NONE;
 	}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/servlet/WebMvcTags.java

@@ -136,7 +136,8 @@ public final class WebMvcTags {
 	public static Tag exception(Throwable exception) {
 		if (exception != null) {
 			String simpleName = exception.getClass().getSimpleName();
-			return Tag.of("exception", simpleName.isEmpty() ? exception.getClass().getName() : simpleName);
+			return Tag.of("exception", StringUtils.hasText(simpleName) ? simpleName
+					: exception.getClass().getName());
 		}
 		return EXCEPTION_NONE;
 	}

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/web/reactive/server/MetricsWebFilterTests.java

@@ -82,14 +82,12 @@ public class MetricsWebFilterTests {
 
 	@Test
 	public void filterAddsNonEmptyTagsToRegistryForAnonymousExceptions() {
-		final Exception anonymous = new Exception("test error") {};
+		final Exception anonymous = new Exception("test error") {
+		};
 
 		MockServerWebExchange exchange = createExchange("/projects/spring-boot",
 				"/projects/{project}");
-		this.webFilter
+		this.webFilter.filter(exchange, (serverWebExchange) -> Mono.error(anonymous))
-				.filter(exchange,
-						(serverWebExchange) -> Mono
-								.error(anonymous))
 				.onErrorResume((t) -> {
 					exchange.getResponse().setStatusCodeValue(500);
 					return exchange.getResponse().setComplete();

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/web/servlet/WebMvcMetricsFilterTests.java

@@ -189,15 +189,15 @@ public class WebMvcMetricsFilterTests {
 	}
 
 	@Test
-	public void anonymousError() throws Exception {
+	public void anonymousError() {
 		try {
-			mvc.perform(get("/api/c1/anonymousError/10"));
+			this.mvc.perform(get("/api/c1/anonymousError/10"));
-		} catch(Throwable ignore) {
 		}
-
+		catch (Throwable ignore) {
-		assertThat(this.registry.get("http.server.requests").tag("uri", "/api/c1/anonymousError/{id}").timer().getId()
+		}
-				.getTag("exception"))
+		assertThat(this.registry.get("http.server.requests")
-				.endsWith("$1");
+				.tag("uri", "/api/c1/anonymousError/{id}").timer().getId()
+				.getTag("exception")).endsWith("$1");
 	}
 
 	@Test
@@ -454,8 +454,10 @@ public class WebMvcMetricsFilterTests {
 
 		@Timed
 		@GetMapping("/anonymousError/{id}")
-		public String alwaysThrowsAnonymousException(@PathVariable Long id) throws Exception {
+		public String alwaysThrowsAnonymousException(@PathVariable Long id)
-			throw new Exception("this exception won't have a simple class name") {};
+				throws Exception {
+			throw new Exception("this exception won't have a simple class name") {
+			};
 		}
 
 		@Timed