added a zipkin servlet filter

pom.xml

@@ -94,6 +94,11 @@
 				<artifactId>flume-zipkin-metrics-sink</artifactId>
 				<version>${brave.version}</version>
 			</dependency>
+			<dependency>
+				<groupId>com.google.guava</groupId>
+				<artifactId>guava</artifactId>
+				<version>18.0</version>
+			</dependency>
 			<dependency>
 				<groupId>org.springframework.cloud</groupId>
 				<artifactId>spring-cloud-starter-zuul</artifactId>

spring-cloud-sleuth-zipkin/pom.xml

@@ -50,6 +50,10 @@
 			<groupId>org.springframework.cloud</groupId>
 			<artifactId>spring-cloud-starter-zuul</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>com.google.guava</groupId>
+			<artifactId>guava</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.projectlombok</groupId>
 			<artifactId>lombok</artifactId>

spring-cloud-sleuth-zipkin/src/main/java/org/springframework/cloud/sleuth/zipkin/ZipkinAutoConfiguration.java

@@ -16,7 +16,6 @@ import com.github.kristofa.brave.ClientTracer;
 import com.github.kristofa.brave.ClientTracerConfig;
 import com.github.kristofa.brave.EndPointSubmitterConfig;
 import com.github.kristofa.brave.FixedSampleRateTraceFilter;
-import com.github.kristofa.brave.LoggingSpanCollectorImpl;
 import com.github.kristofa.brave.ServerSpanThreadBinderConfig;
 import com.github.kristofa.brave.ServerTracerConfig;
 import com.github.kristofa.brave.SpanCollector;

spring-cloud-sleuth-zipkin/src/main/java/org/springframework/cloud/sleuth/zipkin/web/ZipkinFilter.java

@@ -0,0 +1,43 @@
+package org.springframework.cloud.sleuth.zipkin.web;
+
+import org.springframework.cloud.sleuth.zipkin.ZipkinInterceptor;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import java.io.IOException;
+
+/**
+ * @author Spencer Gibb
+ */
+public class ZipkinFilter implements Filter {
+
+    private final ZipkinInterceptor zipkinInterceptor;
+
+    public ZipkinFilter(ZipkinInterceptor zipkinInterceptor) {
+        this.zipkinInterceptor = zipkinInterceptor;
+    }
+
+
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException {
+        //NOOP
+    }
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        zipkinInterceptor.preTrace(request);
+
+        chain.doFilter(request, response);
+
+        zipkinInterceptor.postTrace(request);
+    }
+
+    @Override
+    public void destroy() {
+        //NOOP
+    }
+}

spring-cloud-sleuth-zipkin/src/main/java/org/springframework/cloud/sleuth/zipkin/web/ZipkinWebAutoConfiguration.java

@@ -2,6 +2,7 @@ package org.springframework.cloud.sleuth.zipkin.web;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
@@ -34,10 +35,15 @@ public class ZipkinWebAutoConfiguration {
 	@Autowired
 	private ServerTracer serverTracer;
 
-	@Bean
+	/*@Bean
 	public ZipkinHandlerInterceptor zipkinHandlerInterceptor() {
 		return new ZipkinHandlerInterceptor(httpServletRequestInterceptor());
-	}
+	}*/
+
+    @Bean
+    public ZipkinFilter zipkinFilter() {
+        return new ZipkinFilter(httpServletRequestInterceptor());
+    }
 
     @Bean
     public HttpServletRequestInterceptor httpServletRequestInterceptor() {
@@ -45,8 +51,9 @@ public class ZipkinWebAutoConfiguration {
     }
 
 	@Bean
-	public WebMvcConfigurerAdapter webMvcConfigurerAdapter() {
-		return new ZipkinWebConfigurer(zipkinHandlerInterceptor());
+    @ConditionalOnBean(ZipkinHandlerInterceptor.class)
+	public WebMvcConfigurerAdapter webMvcConfigurerAdapter(ZipkinHandlerInterceptor zipkinHandlerInterceptor) {
+		return new ZipkinWebConfigurer(zipkinHandlerInterceptor);
 	}
 
     @Configuration