use typeMapping instead of postProcessParameter (#7457)

Author: wing328

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaVertXWebServerCodegen.java

@@ -68,6 +68,9 @@ public JavaVertXWebServerCodegen() {
 
         // Override type mapping
         typeMapping.put("file", "FileUpload");
+        typeMapping.put("UUID", "String");
+        typeMapping.put("date", "String");
+        typeMapping.put("DateTime", "String");
     }
 
     public CodegenType getTag() {
@@ -160,14 +163,6 @@ public Map<String, Object> postProcessOperationsWithModels(Map<String, Object> o
         return newObjs;
     }
 
-    @Override
-    public void postProcessParameter(CodegenParameter parameter) {
-        super.postProcessParameter(parameter);
-        if (parameter.isUuid || parameter.isDate || parameter.isDateTime) {
-            parameter.dataType = "String";
-        }
-    }
-
     @Override
     public Map<String, Object> postProcessSupportingFileData(Map<String, Object> objs) {
         generateYAMLSpecFile(objs);