support configuring jackson JsonParser. Feature

lib/src/jackson/java/com/diffplug/spotless/glue/json/JacksonJsonFormatterFunc.java

@@ -21,6 +21,7 @@
 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonFactoryBuilder;
 import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.util.DefaultIndenter;
 import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
 import com.fasterxml.jackson.core.util.Separators;
@@ -64,7 +65,12 @@ protected JsonFactory makeJsonFactory() {
 
 			jsonFactory.configure(feature, toggle);
 		});
+		jacksonConfig.getJsonParserFeatureToToggle().forEach((rawFeature, toggle) -> {
+			// https://stackoverflow.com/questions/3735927/java-instantiating-an-enum-using-reflection
+			JsonParser.Feature feature = JsonParser.Feature.valueOf(rawFeature);
 
+			jsonFactory.configure(feature, toggle);
+		});
 		return jsonFactory;
 	}
 

lib/src/main/java/com/diffplug/spotless/json/JacksonJsonConfig.java

@@ -27,6 +27,8 @@ public class JacksonJsonConfig extends JacksonConfig {
 
 	protected Map<String, Boolean> jsonFeatureToToggle = new LinkedHashMap<>();
 
+	protected Map<String, Boolean> jsonParserFeatureToToggle = new LinkedHashMap<>();
+
 	// https://github.com/revelc/formatter-maven-plugin/pull/280
 	// By default, Jackson adds a ' ' before separator, which is not standard with most IDE/JSON libraries
 	protected boolean spaceBeforeSeparator = false;
@@ -35,6 +37,10 @@ public Map<String, Boolean> getJsonFeatureToToggle() {
 		return Collections.unmodifiableMap(jsonFeatureToToggle);
 	}
 
+	public Map<String, Boolean> getJsonParserFeatureToToggle() {
+		return Collections.unmodifiableMap(jsonParserFeatureToToggle);
+	}
+
 	/**
 	 * Refers to com.fasterxml.jackson.core.JsonGenerator.Feature
 	 */
@@ -49,6 +55,13 @@ public void appendJsonFeatureToToggle(Map<String, Boolean> features) {
 		this.jsonFeatureToToggle.putAll(features);
 	}
 
+	/**
+	 * Refers to com.fasterxml.jackson.core.JsonParser.Feature
+	 */
+	public void appendJsonParserFeatureToToggle(Map<String, Boolean> features) {
+		this.jsonParserFeatureToToggle.putAll(features);
+	}
+
 	public boolean isSpaceBeforeSeparator() {
 		return spaceBeforeSeparator;
 	}

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/JsonExtension.java

@@ -169,6 +169,15 @@ public JacksonJsonGradleConfig jsonFeature(String feature, boolean toggle) {
 			return this;
 		}
 
+		/**
+		 * Refers to com.fasterxml.jackson.core.JsonParser.Feature
+		 */
+		public JacksonJsonGradleConfig jsonParserFeature(String feature, boolean toggle) {
+			this.jacksonConfig.appendJsonParserFeatureToToggle(Collections.singletonMap(feature, toggle));
+			formatExtension.replaceStep(createStep());
+			return this;
+		}
+
 		@Override
 		public JacksonJsonGradleConfig self() {
 			return this;

plugin-maven/src/main/java/com/diffplug/spotless/maven/json/JacksonJson.java

@@ -44,12 +44,16 @@ public class JacksonJson implements FormatterStepFactory {
 	@Parameter
 	private Map<String, Boolean> jsonFeatures = Collections.emptyMap();
 
+	@Parameter
+	private Map<String, Boolean> jsonParserFeatures = Collections.emptyMap();
+
 	@Override
 	public FormatterStep newFormatterStep(FormatterStepConfig stepConfig) {
 		JacksonJsonConfig jacksonConfig = new JacksonJsonConfig();
 
 		jacksonConfig.appendFeatureToToggle(features);
 		jacksonConfig.appendJsonFeatureToToggle(jsonFeatures);
+		jacksonConfig.appendJsonParserFeatureToToggle(jsonParserFeatures);
 		jacksonConfig.setSpaceBeforeSeparator(spaceBeforeSeparator);
 
 		return JacksonJsonStep