Support java 8 Optional for query parameter

springdoc-openapi-common/src/main/java/org/springdoc/core/AbstractRequestBuilder.java

@@ -263,7 +263,8 @@ private Parameter buildParams(ParameterInfo parameterInfo, Components components
 
 		}
 		else if (requestParam != null) {
-			requestInfo = new RequestInfo(ParameterType.QUERY_PARAM, requestParam.value(), requestParam.required(),
+			boolean isOptional = Optional.class.equals(parameters.getType());
+			requestInfo = new RequestInfo(ParameterType.QUERY_PARAM, requestParam.value(), requestParam.required() && !isOptional,
 					requestParam.defaultValue());
 			parameter = buildParam(parameterInfo, components, requestInfo, jsonView);
 		}

springdoc-openapi-webmvc-core/src/test/java/test/org/springdoc/api/app78/HelloController.java

@@ -0,0 +1,36 @@
+/*
+ *
+ *  * Copyright 2019-2020 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.
+ *  * You may obtain a copy of the License at
+ *  *
+ *  *      https://www.apache.org/licenses/LICENSE-2.0
+ *  *
+ *  * Unless required by applicable law or agreed to in writing, software
+ *  * distributed under the License is distributed on an "AS IS" BASIS,
+ *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  * See the License for the specific language governing permissions and
+ *  * limitations under the License.
+ *
+ */
+
+package test.org.springdoc.api.app78;
+
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.Optional;
+
+@RestController
+public class HelloController {
+
+	@GetMapping(produces = MediaType.TEXT_PLAIN_VALUE, path = "/test")
+	public String echo(@RequestParam Optional<String> text) {
+		return text.orElse("not-specified");
+	}
+
+}

springdoc-openapi-webmvc-core/src/test/java/test/org/springdoc/api/app78/SpringDocApp78Test.java

@@ -0,0 +1,28 @@
+/*
+ *
+ *  * Copyright 2019-2020 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.
+ *  * You may obtain a copy of the License at
+ *  *
+ *  *      https://www.apache.org/licenses/LICENSE-2.0
+ *  *
+ *  * Unless required by applicable law or agreed to in writing, software
+ *  * distributed under the License is distributed on an "AS IS" BASIS,
+ *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  * See the License for the specific language governing permissions and
+ *  * limitations under the License.
+ *
+ */
+
+package test.org.springdoc.api.app78;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import test.org.springdoc.api.AbstractSpringDocTest;
+
+public class SpringDocApp78Test extends AbstractSpringDocTest {
+
+	@SpringBootApplication
+	static class SpringDocTestApp {}
+}

springdoc-openapi-webmvc-core/src/test/resources/results/app78.json

@@ -0,0 +1,46 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "OpenAPI definition",
+    "version": "v0"
+  },
+  "servers": [
+    {
+      "url": "http://localhost",
+      "description": "Generated server url"
+    }
+  ],
+  "paths": {
+    "/test": {
+      "get": {
+        "tags": [
+          "hello-controller"
+        ],
+        "operationId": "echo",
+        "parameters": [
+          {
+            "name": "text",
+            "in": "query",
+            "required": false,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "default response",
+            "content": {
+              "text/plain": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "components": {}
+}