Remove @ControllerAdvice from BasicErrorController

Update the BasicErrorController so that it no longer needs to implement
@ControllerAdvice or have an @ExceptionHandler method.

A new ErrorAttributes interface is now used to obtain error details,
the DefaultErrorAttributes implementation uses a
HandlerExceptionResolver to obtain root exception details if the
`javax.servlet.error.*` attributes are missing.

This change also removes the need for the extract(...) method on
ErrorController as classes such as WebRequestTraceFilter can
now use the ErrorAttributes interface directly.

See gh-839, gh-538
Fixes gh-843

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/EndpointWebMvcChildContextConfiguration.java

@@ -34,7 +34,7 @@ import org.springframework.boot.actuate.endpoint.mvc.MvcEndpoints;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.SearchStrategy;
-import org.springframework.boot.autoconfigure.web.ErrorController;
+import org.springframework.boot.autoconfigure.web.ErrorAttributes;
 import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
 import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
 import org.springframework.boot.context.embedded.EmbeddedServletContainer;
@@ -125,12 +125,11 @@ public class EndpointWebMvcChildContextConfiguration {
 	/*
 	 * The error controller is present but not mapped as an endpoint in this context
 	 * because of the DispatcherServlet having had it's HandlerMapping explicitly
-	 * disabled. So this tiny shim exposes the same feature but only for machine
-	 * endpoints.
+	 * disabled. So we expose the same feature but only for machine endpoints.
 	 */
 	@Bean
-	public ManagementErrorEndpoint errorEndpoint(final ErrorController controller) {
-		return new ManagementErrorEndpoint(this.errorPath, controller);
+	public ManagementErrorEndpoint errorEndpoint(final ErrorAttributes errorAttributes) {
+		return new ManagementErrorEndpoint(this.errorPath, errorAttributes);
 	}
 
 	@Configuration

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/TraceWebFilterAutoConfiguration.java

@@ -27,7 +27,7 @@ import org.springframework.boot.actuate.trace.WebRequestTraceFilter;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
-import org.springframework.boot.autoconfigure.web.BasicErrorController;
+import org.springframework.boot.autoconfigure.web.ErrorAttributes;
 import org.springframework.context.annotation.Bean;
 import org.springframework.web.servlet.DispatcherServlet;
 
@@ -45,7 +45,7 @@ public class TraceWebFilterAutoConfiguration {
 	private TraceRepository traceRepository;
 
 	@Autowired(required = false)
-	private BasicErrorController errorController;
+	private ErrorAttributes errorAttributes;
 
 	@Value("${management.dump_requests:false}")
 	private boolean dumpRequests;
@@ -54,8 +54,8 @@ public class TraceWebFilterAutoConfiguration {
 	public WebRequestTraceFilter webRequestLoggingFilter(BeanFactory beanFactory) {
 		WebRequestTraceFilter filter = new WebRequestTraceFilter(this.traceRepository);
 		filter.setDumpRequests(this.dumpRequests);
-		if (this.errorController != null) {
-			filter.setErrorController(this.errorController);
+		if (this.errorAttributes != null) {
+			filter.setErrorAttributes(this.errorAttributes);
 		}
 		return filter;
 	}

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/mvc/ManagementErrorEndpoint.java

@@ -19,12 +19,12 @@ package org.springframework.boot.actuate.endpoint.mvc;
 import java.util.Map;
 
 import org.springframework.boot.actuate.endpoint.Endpoint;
+import org.springframework.boot.autoconfigure.web.ErrorAttributes;
 import org.springframework.boot.autoconfigure.web.ErrorController;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.util.Assert;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;
-import org.springframework.web.context.request.RequestAttributes;
 import org.springframework.web.context.request.RequestContextHolder;
 
 /**
@@ -37,21 +37,21 @@ import org.springframework.web.context.request.RequestContextHolder;
 @ConfigurationProperties(prefix = "error")
 public class ManagementErrorEndpoint implements MvcEndpoint {
 
-	private final ErrorController controller;
+	private final ErrorAttributes errorAttributes;
 
 	private final String path;
 
-	public ManagementErrorEndpoint(String path, ErrorController controller) {
-		Assert.notNull(controller, "Controller must not be null");
+	public ManagementErrorEndpoint(String path, ErrorAttributes errorAttributes) {
+		Assert.notNull(errorAttributes, "ErrorAttributes must not be null");
 		this.path = path;
-		this.controller = controller;
+		this.errorAttributes = errorAttributes;
 	}
 
 	@RequestMapping
 	@ResponseBody
 	public Map<String, Object> invoke() {
-		RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
-		return this.controller.extract(attributes, false, true);
+		return this.errorAttributes.getErrorAttributes(
+				RequestContextHolder.currentRequestAttributes(), false);
 	}
 
 	@Override

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/trace/WebRequestTraceFilter.java

@@ -34,8 +34,9 @@ import javax.servlet.http.HttpServletResponse;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.springframework.boot.autoconfigure.web.BasicErrorController;
+import org.springframework.boot.autoconfigure.web.ErrorAttributes;
 import org.springframework.core.Ordered;
+import org.springframework.web.context.request.RequestAttributes;
 import org.springframework.web.context.request.ServletRequestAttributes;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
@@ -58,7 +59,7 @@ public class WebRequestTraceFilter implements Filter, Ordered {
 
 	private final ObjectMapper objectMapper = new ObjectMapper();
 
-	private BasicErrorController errorController;
+	private ErrorAttributes errorAttributes;
 
 	/**
 	 * @param traceRepository
@@ -156,13 +157,13 @@ public class WebRequestTraceFilter implements Filter, Ordered {
 		trace.put("method", request.getMethod());
 		trace.put("path", request.getRequestURI());
 		trace.put("headers", allHeaders);
-		Throwable error = (Throwable) request
+		Throwable exception = (Throwable) request
 				.getAttribute("javax.servlet.error.exception");
-		if (error != null) {
-			if (this.errorController != null) {
-				trace.put("error", this.errorController.extract(
-						new ServletRequestAttributes(request), true, false));
-			}
+		if (exception != null && this.errorAttributes != null) {
+			RequestAttributes requestAttributes = new ServletRequestAttributes(request);
+			Map<String, Object> error = this.errorAttributes.getErrorAttributes(
+					requestAttributes, true);
+			trace.put("error", error);
 		}
 		return trace;
 	}
@@ -175,8 +176,8 @@ public class WebRequestTraceFilter implements Filter, Ordered {
 	public void destroy() {
 	}
 
-	public void setErrorController(BasicErrorController errorController) {
-		this.errorController = errorController;
+	public void setErrorAttributes(ErrorAttributes errorAttributes) {
+		this.errorAttributes = errorAttributes;
 	}
 
 }

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/trace/WebRequestTraceFilterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2014 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.
@@ -19,7 +19,7 @@ package org.springframework.boot.actuate.trace;
 import java.util.Map;
 
 import org.junit.Test;
-import org.springframework.boot.autoconfigure.web.BasicErrorController;
+import org.springframework.boot.autoconfigure.web.DefaulErrorAttributes;
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.mock.web.MockHttpServletResponse;
 
@@ -76,7 +76,7 @@ public class WebRequestTraceFilterTests {
 
 	@Test
 	public void filterHasError() {
-		this.filter.setErrorController(new BasicErrorController());
+		this.filter.setErrorAttributes(new DefaulErrorAttributes());
 		MockHttpServletRequest request = new MockHttpServletRequest("GET", "/foo");
 		MockHttpServletResponse response = new MockHttpServletResponse();
 		response.setStatus(500);