update RequestParamParameterProcessor to support map param

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/annotation/RequestParamParameterProcessor.java

@@ -47,15 +47,18 @@ public class RequestParamParameterProcessor implements AnnotatedParameterProcess
 			Annotation annotation) {
 		RequestParam requestParam = ANNOTATION.cast(annotation);
 		String name = requestParam.value();
-		checkState(emptyToNull(name) != null,
-				"RequestParam.value() was empty on parameter %s",
-				context.getParameterIndex());
+		if (emptyToNull(name) != null) {
 			context.setParameterName(name);
 
 			MethodMetadata data = context.getMethodMetadata();
 			Collection<String> query = context.setTemplateParameter(name,
 					data.template().queries().get(name));
 			data.template().query(name, query);
+		} else {
+			// supports `Map` types
+			MethodMetadata data = context.getMethodMetadata();
+			data.queryMapIndex(context.getParameterIndex());
+		}
 		return true;
 	}
 }

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/support/SpringMvcContract.java

@@ -18,6 +18,7 @@ package org.springframework.cloud.netflix.feign.support;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Method;
+import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -27,6 +28,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.beans.BeanUtils;
 import org.springframework.cloud.netflix.feign.AnnotatedParameterProcessor;
 import org.springframework.cloud.netflix.feign.annotation.PathVariableParameterProcessor;
 import org.springframework.cloud.netflix.feign.annotation.RequestHeaderParameterProcessor;
@@ -313,8 +315,9 @@ public class SpringMvcContract extends Contract.BaseContract
 		Object defaultValue = AnnotationUtils.getDefaultValue(parameterAnnotation);
 		if (defaultValue instanceof String
 				&& defaultValue.equals(annotationAttributes.get(AnnotationUtils.VALUE))) {
+			Type[] parameterTypes = method.getGenericParameterTypes();
 			String[] parameterNames = PARAMETER_NAME_DISCOVERER.getParameterNames(method);
-			if (parameterNames != null && parameterNames.length > parameterIndex) {
+			if (shouldAddParameterName(parameterIndex, parameterTypes, parameterNames)) {
 				annotationAttributes.put(AnnotationUtils.VALUE,
 						parameterNames[parameterIndex]);
 			}
@@ -323,6 +326,15 @@ public class SpringMvcContract extends Contract.BaseContract
 				parameterAnnotation.annotationType(), null);
 	}
 
+	private boolean shouldAddParameterName(int parameterIndex, Type[] parameterTypes, String[] parameterNames) {
+		// has a parameter name
+		return parameterNames != null && parameterNames.length > parameterIndex
+				// has a type
+				&& parameterTypes != null && parameterTypes.length > parameterIndex
+				// and it is a simple property
+				&& BeanUtils.isSimpleProperty(parameterTypes[parameterIndex].getClass());
+	}
+
 	private class SimpleAnnotatedParameterContext
 			implements AnnotatedParameterProcessor.AnnotatedParameterContext {
 

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/feign/support/SpringMvcContractTests.java

@@ -19,6 +19,7 @@ package org.springframework.cloud.netflix.feign.support;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.List;
+import java.util.Map;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -263,6 +264,19 @@ public class SpringMvcContractTests {
 	}
 
 	@Test
+	public void testProcessAnnotations_MapParams() throws Exception {
+		Method method = TestTemplate_MapParams.class.getDeclaredMethod("getTest",
+				Map.class);
+		MethodMetadata data = this.contract
+				.parseAndValidateMetadata(method.getDeclaringClass(), method);
+
+		assertEquals("/test", data.template().url());
+		assertEquals("GET", data.template().method());
+		assertNotNull(data.queryMapIndex());
+		assertEquals(0, data.queryMapIndex().intValue());
+	}
+
+	@Test
 	public void testProcessHeaders() throws Exception {
 		Method method = TestTemplate_Headers.class.getDeclaredMethod("getTest",
 				String.class);
@@ -279,7 +293,7 @@ public class SpringMvcContractTests {
 		Method method = TestTemplate_Advanced.class.getDeclaredMethod("getTestFallback",
 				String.class, String.class, Integer.class);
 
-		assumeTrue(hasJava8ParameterNames(method));
+		assumeTrue("does not have java 8 parameter names", hasJava8ParameterNames(method));
 
 		MethodMetadata data = this.contract
 				.parseAndValidateMetadata(method.getDeclaringClass(), method);
@@ -361,6 +375,11 @@ public class SpringMvcContractTests {
 		ResponseEntity<TestObject> getTest(@RequestParam("id") List<String> id);
 	}
 
+	public interface TestTemplate_MapParams {
+		@RequestMapping(value = "/test", method = RequestMethod.GET)
+		ResponseEntity<TestObject> getTest(@RequestParam Map<String, String> params);
+	}
+
 	@JsonAutoDetect
 	@RequestMapping("/advanced")
 	public interface TestTemplate_Advanced {