update to get method name

Author: cuichenli

instrumentation/spring/spring-webflux/spring-webflux-5.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/spring/webflux/v5_0/server/HandlerCodeAttributesGetter.java

@@ -25,6 +25,10 @@ public Class<?> getCodeClass(Object handler) {
   @Nullable
   @Override
   public String getMethodName(Object handler) {
+    if (handler instanceof HandlerMethod) {
+      HandlerMethod handlerMethod = (HandlerMethod) handler;
+      return handlerMethod.getMethod().getName();
+    }
     return "handle";
   }
 }

instrumentation/spring/spring-webflux/spring-webflux-5.0/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/spring/webflux/v5_0/server/SpringWebfluxTest.java

@@ -139,7 +139,11 @@ void basicGetTest(Parameter parameter) {
                   span.hasKind(SpanKind.INTERNAL)
                       .hasParent(trace.getSpan(0))
                       .hasAttributesSatisfyingExactly(
-                          equalTo(CODE_FUNCTION, "handle"),
+                          satisfies(
+                              CODE_FUNCTION,
+                              parameter.annotatedMethod == null
+                                  ? val -> val.isEqualTo("handle")
+                                  : val -> val.isEqualTo(parameter.annotatedMethod)),
                           satisfies(
                               CODE_NAMESPACE,
                               parameter.annotatedMethod == null
@@ -259,7 +263,11 @@ void getAsyncResponseTest(Parameter parameter) {
                   span.hasKind(SpanKind.INTERNAL)
                       .hasParent(trace.getSpan(0))
                       .hasAttributesSatisfyingExactly(
-                          equalTo(CODE_FUNCTION, "handle"),
+                          satisfies(
+                              CODE_FUNCTION,
+                              parameter.annotatedMethod == null
+                                  ? val -> val.isEqualTo("handle")
+                                  : val -> val.isEqualTo(parameter.annotatedMethod)),
                           satisfies(
                               CODE_NAMESPACE,
                               parameter.annotatedMethod == null
@@ -366,7 +374,11 @@ void createSpanDuringHandlerFunctionTest(Parameter parameter) {
                   span.hasKind(SpanKind.INTERNAL)
                       .hasParent(trace.getSpan(0))
                       .hasAttributesSatisfyingExactly(
-                          equalTo(CODE_FUNCTION, "handle"),
+                          satisfies(
+                              CODE_FUNCTION,
+                              parameter.annotatedMethod == null
+                                  ? val -> val.isEqualTo("handle")
+                                  : val -> val.isEqualTo(parameter.annotatedMethod)),
                           satisfies(
                               CODE_NAMESPACE,
                               parameter.annotatedMethod == null
@@ -548,7 +560,11 @@ void getToBadEndpointTest(Parameter parameter) {
                                           EXCEPTION_STACKTRACE,
                                           val -> val.isInstanceOf(String.class))))
                       .hasAttributesSatisfyingExactly(
-                          equalTo(CODE_FUNCTION, "handle"),
+                          satisfies(
+                              CODE_FUNCTION,
+                              parameter.annotatedMethod == null
+                                  ? val -> val.isEqualTo("handle")
+                                  : val -> val.isEqualTo(parameter.annotatedMethod)),
                           satisfies(
                               CODE_NAMESPACE,
                               parameter.annotatedMethod == null
@@ -695,7 +711,11 @@ void multipleGetsToDelayingRoute(Parameter parameter) {
                   span.hasKind(SpanKind.INTERNAL)
                       .hasParent(trace.getSpan(0))
                       .hasAttributesSatisfyingExactly(
-                          equalTo(CODE_FUNCTION, "handle"),
+                          satisfies(
+                              CODE_FUNCTION,
+                              parameter.annotatedMethod == null
+                                  ? val -> val.isEqualTo("handle")
+                                  : val -> val.isEqualTo(parameter.annotatedMethod)),
                           satisfies(
                               CODE_NAMESPACE,
                               parameter.annotatedMethod == null