Remove spring-web dependency from ZipkinHttpClientSender

Closes gh-42160

Author: mhalbritter

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/HttpSender.java

@@ -27,7 +27,8 @@
 import zipkin2.reporter.Encoding;
 import zipkin2.reporter.HttpEndpointSupplier.Factory;
 
-import org.springframework.http.HttpHeaders;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
 import org.springframework.util.unit.DataSize;
 
 /**
@@ -60,20 +61,20 @@ protected byte[] newBody(List<byte[]> list) {
 
 	@Override
 	protected void postSpans(URI endpoint, byte[] body) throws IOException {
-		HttpHeaders headers = getDefaultHeaders();
+		MultiValueMap<String, String> headers = getDefaultHeaders();
 		if (needsCompression(body)) {
 			body = compress(body);
-			headers.set("Content-Encoding", "gzip");
+			headers.add("Content-Encoding", "gzip");
 		}
 		postSpans(endpoint, headers, body);
 	}
 
-	abstract void postSpans(URI endpoint, HttpHeaders headers, byte[] body) throws IOException;
+	abstract void postSpans(URI endpoint, MultiValueMap<String, String> headers, byte[] body) throws IOException;
 
-	HttpHeaders getDefaultHeaders() {
-		HttpHeaders headers = new HttpHeaders();
-		headers.set("b3", "0");
-		headers.set("Content-Type", this.encoding.mediaType());
+	MultiValueMap<String, String> getDefaultHeaders() {
+		MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
+		headers.add("b3", "0");
+		headers.add("Content-Type", this.encoding.mediaType());
 		return headers;
 	}
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinHttpClientSender.java

@@ -29,7 +29,7 @@
 import zipkin2.reporter.Encoding;
 import zipkin2.reporter.HttpEndpointSupplier.Factory;
 
-import org.springframework.http.HttpHeaders;
+import org.springframework.util.MultiValueMap;
 
 /**
  * A {@link HttpSender} which uses the JDK {@link HttpClient} for HTTP communication.
@@ -50,7 +50,7 @@ class ZipkinHttpClientSender extends HttpSender {
 	}
 
 	@Override
-	void postSpans(URI endpoint, HttpHeaders headers, byte[] body) throws IOException {
+	void postSpans(URI endpoint, MultiValueMap<String, String> headers, byte[] body) throws IOException {
 		Builder request = HttpRequest.newBuilder()
 			.POST(BodyPublishers.ofByteArray(body))
 			.uri(endpoint)

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinRestTemplateSender.java

@@ -22,8 +22,8 @@
 import zipkin2.reporter.HttpEndpointSupplier.Factory;
 
 import org.springframework.http.HttpEntity;
-import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
+import org.springframework.util.MultiValueMap;
 import org.springframework.web.client.RestTemplate;
 
 /**
@@ -45,7 +45,7 @@ class ZipkinRestTemplateSender extends HttpSender {
 	}
 
 	@Override
-	void postSpans(URI endpoint, HttpHeaders headers, byte[] body) {
+	void postSpans(URI endpoint, MultiValueMap<String, String> headers, byte[] body) {
 		HttpEntity<byte[]> request = new HttpEntity<>(body, headers);
 		this.restTemplate.exchange(endpoint, HttpMethod.POST, request, Void.class);
 	}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinWebClientSender.java

@@ -22,7 +22,7 @@
 import zipkin2.reporter.Encoding;
 import zipkin2.reporter.HttpEndpointSupplier.Factory;
 
-import org.springframework.http.HttpHeaders;
+import org.springframework.util.MultiValueMap;
 import org.springframework.web.reactive.function.client.WebClient;
 
 /**
@@ -47,7 +47,7 @@ class ZipkinWebClientSender extends HttpSender {
 	}
 
 	@Override
-	void postSpans(URI endpoint, HttpHeaders headers, byte[] body) {
+	void postSpans(URI endpoint, MultiValueMap<String, String> headers, byte[] body) {
 		this.webClient.post()
 			.uri(endpoint)
 			.headers((h) -> h.addAll(headers))

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinHttpClientSenderTests.java

@@ -35,6 +35,8 @@
 import zipkin2.reporter.HttpEndpointSupplier;
 import zipkin2.reporter.HttpEndpointSuppliers;
 
+import org.springframework.boot.testsupport.classpath.ClassPathExclusions;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatException;
 import static org.assertj.core.api.Assertions.assertThatIOException;
@@ -44,6 +46,7 @@
  *
  * @author Moritz Halbritter
  */
+@ClassPathExclusions("spring-web-*.jar")
 class ZipkinHttpClientSenderTests extends ZipkinHttpSenderTests {
 
 	private MockWebServer mockBackEnd;