enable generating html file with mojo

Author: Nithin Tatikonda

maven/src/main/java/org/openapitools/openapidiff/maven/OpenApiDiffMojo.java

@@ -9,6 +9,11 @@
 import org.openapitools.openapidiff.core.OpenApiCompare;
 import org.openapitools.openapidiff.core.model.ChangedOpenApi;
 import org.openapitools.openapidiff.core.output.ConsoleRender;
+import org.openapitools.openapidiff.core.output.HtmlRender;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
 
 /** A Maven Mojo that diffs two OpenAPI specifications and reports on differences. */
 @Mojo(name = "diff", defaultPhase = LifecyclePhase.TEST)
@@ -25,6 +30,12 @@ public class OpenApiDiffMojo extends AbstractMojo {
   @Parameter(property = "failOnChanged", defaultValue = "false")
   Boolean failOnChanged = false;
 
+  @Parameter(property = "outputType")
+  String outputType;
+
+  @Parameter(property = "outputFile")
+  String outputFile;
+
   @Parameter(property = "skip", defaultValue = "false")
   Boolean skip = false;
 
@@ -37,7 +48,24 @@ public void execute() throws MojoExecutionException, MojoFailureException {
 
     try {
       final ChangedOpenApi diff = OpenApiCompare.fromLocations(oldSpec, newSpec);
-      getLog().info(new ConsoleRender().render(diff));
+
+      if (outputType == null || outputType.equals("")) {
+        getLog().info(new ConsoleRender().render(diff));
+      }
+
+      if (outputType.equalsIgnoreCase("html") || outputType.equalsIgnoreCase("html-detailed")) {
+        boolean detailed = outputType.equalsIgnoreCase("html-detailed");
+        File htmlFile = new File(outputFile);
+        String htmlRender = new HtmlRender(detailed).render(diff);
+        try {
+          FileWriter fileWriter = new FileWriter(htmlFile);
+          fileWriter.write(htmlRender);
+          fileWriter.close();
+
+        } catch (IOException e) {
+          throw new RuntimeException(e.getMessage());
+        }
+      }
 
       if (failOnIncompatible && diff.isIncompatible()) {
         throw new BackwardIncompatibilityException("The API changes broke backward compatibility");