Skip null header/form parameters

and fix the bug of getting file name for file parameter

Author: xhh

modules/swagger-codegen/src/main/resources/Java/api.mustache

@@ -68,7 +68,8 @@ public class {{classname}} {
     {{#queryParams}}if ({{paramName}} != null)
       queryParams.put("{{baseName}}", apiClient.parameterToString({{paramName}}));
     {{/queryParams}}
-    {{#headerParams}}headerParams.put("{{baseName}}", apiClient.parameterToString({{paramName}}));
+    {{#headerParams}}if ({{paramName}} != null)
+      headerParams.put("{{baseName}}", apiClient.parameterToString({{paramName}}));
     {{/headerParams}}
     String[] contentTypes = {
       {{#consumes}}"{{mediaType}}"{{#hasMore}},{{/hasMore}}{{/consumes}}
@@ -80,18 +81,23 @@ public class {{classname}} {
       boolean hasFields = false;
       FormDataMultiPart mp = new FormDataMultiPart();
       {{#formParams}}{{#notFile}}
-      hasFields = true;
-      mp.field("{{baseName}}", apiClient.parameterToString({{paramName}}), MediaType.MULTIPART_FORM_DATA_TYPE);
+      if ({{paramName}} != null) {
+        hasFields = true;
+        mp.field("{{baseName}}", apiClient.parameterToString({{paramName}}), MediaType.MULTIPART_FORM_DATA_TYPE);
+      }
       {{/notFile}}{{#isFile}}
-      hasFields = true;
-      mp.field("{{baseName}}", file.getName());
-      mp.bodyPart(new FileDataBodyPart("{{baseName}}", {{paramName}}, MediaType.MULTIPART_FORM_DATA_TYPE));
+      if ({{paramName}} != null) {
+        hasFields = true;
+        mp.field("{{baseName}}", {{paramName}}.getName());
+        mp.bodyPart(new FileDataBodyPart("{{baseName}}", {{paramName}}, MediaType.MULTIPART_FORM_DATA_TYPE));
+      }
       {{/isFile}}{{/formParams}}
       if(hasFields)
         postBody = mp;
     }
     else {
-      {{#formParams}}{{#notFile}}formParams.put("{{baseName}}", apiClient.parameterToString({{paramName}}));{{/notFile}}
+      {{#formParams}}{{#notFile}}if ({{paramName}} != null)
+        formParams.put("{{baseName}}", apiClient.parameterToString({{paramName}}));{{/notFile}}
       {{/formParams}}
     }
 

samples/client/petstore/java/src/main/java/io/swagger/client/api/PetApi.java

@@ -338,18 +338,24 @@ public void updatePetWithForm (String petId, String name, String status) throws
       boolean hasFields = false;
       FormDataMultiPart mp = new FormDataMultiPart();
 
-      hasFields = true;
-      mp.field("name", apiClient.parameterToString(name), MediaType.MULTIPART_FORM_DATA_TYPE);
+      if (name != null) {
+        hasFields = true;
+        mp.field("name", apiClient.parameterToString(name), MediaType.MULTIPART_FORM_DATA_TYPE);
+      }
 
-      hasFields = true;
-      mp.field("status", apiClient.parameterToString(status), MediaType.MULTIPART_FORM_DATA_TYPE);
+      if (status != null) {
+        hasFields = true;
+        mp.field("status", apiClient.parameterToString(status), MediaType.MULTIPART_FORM_DATA_TYPE);
+      }
 
       if(hasFields)
         postBody = mp;
     }
     else {
-      formParams.put("name", apiClient.parameterToString(name));
-      formParams.put("status", apiClient.parameterToString(status));
+      if (name != null)
+        formParams.put("name", apiClient.parameterToString(name));
+      if (status != null)
+        formParams.put("status", apiClient.parameterToString(status));
 
     }
 
@@ -392,7 +398,8 @@ public void deletePet (String apiKey, Long petId) throws ApiException {
     Map<String, String> formParams = new HashMap<String, String>();
 
 
-    headerParams.put("api_key", apiClient.parameterToString(apiKey));
+    if (apiKey != null)
+      headerParams.put("api_key", apiClient.parameterToString(apiKey));
 
     String[] contentTypes = {
 
@@ -462,18 +469,23 @@ public void uploadFile (Long petId, String additionalMetadata, File file) throws
       boolean hasFields = false;
       FormDataMultiPart mp = new FormDataMultiPart();
 
-      hasFields = true;
-      mp.field("additionalMetadata", apiClient.parameterToString(additionalMetadata), MediaType.MULTIPART_FORM_DATA_TYPE);
+      if (additionalMetadata != null) {
+        hasFields = true;
+        mp.field("additionalMetadata", apiClient.parameterToString(additionalMetadata), MediaType.MULTIPART_FORM_DATA_TYPE);
+      }
 
-      hasFields = true;
-      mp.field("file", file.getName());
-      mp.bodyPart(new FileDataBodyPart("file", file, MediaType.MULTIPART_FORM_DATA_TYPE));
+      if (file != null) {
+        hasFields = true;
+        mp.field("file", file.getName());
+        mp.bodyPart(new FileDataBodyPart("file", file, MediaType.MULTIPART_FORM_DATA_TYPE));
+      }
 
       if(hasFields)
         postBody = mp;
     }
     else {
-      formParams.put("additionalMetadata", apiClient.parameterToString(additionalMetadata));
+      if (additionalMetadata != null)
+        formParams.put("additionalMetadata", apiClient.parameterToString(additionalMetadata));
 
 
     }