Add @ResponseStatus handler to global exception handler

We might need to revisit this to allow more fine-grained
control by users, but it seems like a sensible default.
The BasicErrorController now uses both of the deafult strategies
(ResponseStatusExceptionResolver and DefaultHandlerExceptionResolver)
from Spring MVC to try and determine an appropriate response.

Fixes gh-839

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/BasicErrorController.java

@@ -43,6 +43,7 @@ import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.context.request.RequestAttributes;
 import org.springframework.web.context.request.ServletRequestAttributes;
 import org.springframework.web.servlet.ModelAndView;
+import org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver;
 import org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver;
 
 /**
@@ -65,6 +66,8 @@ public class BasicErrorController implements ErrorController {
 
 	private DefaultHandlerExceptionResolver resolver = new DefaultHandlerExceptionResolver();
 
+	private ResponseStatusExceptionResolver statuses = new ResponseStatusExceptionResolver();
+
 	@Value("${error.path:/error}")
 	private String errorPath;
 
@@ -76,7 +79,9 @@ public class BasicErrorController implements ErrorController {
 	@ExceptionHandler(Exception.class)
 	public void handle(HttpServletRequest request, HttpServletResponse response,
 			Exception e) throws Exception {
-		this.resolver.resolveException(request, response, null, e);
+		if (this.statuses.resolveException(request, response, null, e) == null) {
+			this.resolver.resolveException(request, response, null, e);
+		}
 		if (response.getStatus() == HttpServletResponse.SC_OK) {
 			response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
 		}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/BasicErrorControllerIntegrationTests.java

@@ -36,6 +36,7 @@ import org.springframework.boot.autoconfigure.web.BasicErrorControllerIntegratio
 import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.test.annotation.DirtiesContext;
@@ -47,6 +48,7 @@ import org.springframework.test.web.servlet.RequestBuilder;
 import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 import org.springframework.validation.BindException;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.context.WebApplicationContext;
 import org.springframework.web.servlet.View;
@@ -93,6 +95,16 @@ public class BasicErrorControllerIntegrationTests {
 		assertTrue("Wrong content: " + content, content.contains("Expected!"));
 	}
 
+	@Test
+	public void testErrorWithResponseStatus() throws Exception {
+		MvcResult result = this.mockMvc.perform(get("/bang"))
+				.andExpect(status().isNotFound()).andReturn();
+		MvcResult response = this.mockMvc.perform(new ErrorDispatcher(result, "/error"))
+				.andReturn();
+		String content = response.getResponse().getContentAsString();
+		assertTrue("Wrong content: " + content, content.contains("Expected!"));
+	}
+
 	@Test
 	public void testBindingExceptionForMachineClient() throws Exception {
 		// In a real container the response is carried over into the error dispatcher, but
@@ -151,6 +163,11 @@ public class BasicErrorControllerIntegrationTests {
 				throw new IllegalStateException("Expected!");
 			}
 
+			@RequestMapping("/bang")
+			public String bang() {
+				throw new NotFoundException("Expected!");
+			}
+
 			@RequestMapping("/bind")
 			public String bind() throws Exception {
 				BindException error = new BindException(this, "test");
@@ -162,6 +179,15 @@ public class BasicErrorControllerIntegrationTests {
 
 	}
 
+	@ResponseStatus(value = HttpStatus.NOT_FOUND)
+	private static class NotFoundException extends RuntimeException {
+
+		public NotFoundException(String string) {
+			super(string);
+		}
+
+	}
+
 	private class ErrorDispatcher implements RequestBuilder {
 
 		private MvcResult result;