Tolerate custom response status in WebMvcTags

Closes gh-11263

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

@@ -68,11 +68,11 @@ public final class WebMvcTags {
 	 */
 	public static Tag uri(HttpServletRequest request, HttpServletResponse response) {
 		if (response != null) {
-			HttpStatus status = HttpStatus.valueOf(response.getStatus());
-			if (status.is3xxRedirection()) {
+			HttpStatus status = extractStatus(response);
+			if (status != null && status.is3xxRedirection()) {
 				return Tag.of("uri", "REDIRECTION");
 			}
-			if (status.equals(HttpStatus.NOT_FOUND)) {
+			if (HttpStatus.NOT_FOUND.equals(status)) {
 				return Tag.of("uri", "NOT_FOUND");
 			}
 		}
@@ -87,6 +87,15 @@ public final class WebMvcTags {
 		return Tag.of("uri", uri.isEmpty() ? "root" : uri);
 	}
 
+	private static HttpStatus extractStatus(HttpServletResponse response) {
+		try {
+			return HttpStatus.valueOf(response.getStatus());
+		}
+		catch (IllegalArgumentException ex) {
+			return null;
+		}
+	}
+
 	/**
 	 * Creates a {@code exception} tag based on the {@link Class#getSimpleName() simple
 	 * name} of the class of the given {@code exception}.

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/web/servlet/WebMvcTagsTests.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2012-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.endpoint.web.servlet;
+
+import io.micrometer.core.instrument.Tag;
+import org.junit.Test;
+
+import org.springframework.boot.actuate.metrics.web.servlet.WebMvcTags;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link WebMvcTags}.
+ *
+ * @author Andy Wilkinson
+ */
+public class WebMvcTagsTests {
+
+	private final MockHttpServletRequest request = new MockHttpServletRequest();
+
+	private final MockHttpServletResponse response = new MockHttpServletResponse();
+
+	@Test
+	public void uriTagValueIsRedirectionWhenResponseStatusIs3xx() {
+		this.response.setStatus(301);
+		Tag tag = WebMvcTags.uri(this.request, this.response);
+		assertThat(tag.getValue()).isEqualTo("REDIRECTION");
+	}
+
+	@Test
+	public void uriTagValueIsNotFoundWhenResponseStatusIs404() {
+		this.response.setStatus(404);
+		Tag tag = WebMvcTags.uri(this.request, this.response);
+		assertThat(tag.getValue()).isEqualTo("NOT_FOUND");
+	}
+
+	@Test
+	public void uriTagToleratesCustomResponseStatus() {
+		this.response.setStatus(601);
+		Tag tag = WebMvcTags.uri(this.request, this.response);
+		assertThat(tag.getValue()).isEqualTo("/");
+	}
+
+}