Allow encoding to be set with a Charset in FreeMarker support

Closes gh-33102

Author: sbrannen

spring-context-support/src/main/java/org/springframework/ui/freemarker/FreeMarkerConfigurationFactory.java

@@ -18,6 +18,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -146,6 +147,7 @@ public void setFreemarkerVariables(Map<String, Object> variables) {
 	 * <p>Note that the encoding is not used for template rendering. Instead, an
 	 * explicit encoding must be specified for the rendering process &mdash; for
 	 * example, via Spring's {@code FreeMarkerView} or {@code FreeMarkerViewResolver}.
+	 * @see #setDefaultEncoding(Charset)
 	 * @see freemarker.template.Configuration#setDefaultEncoding
 	 * @see org.springframework.web.servlet.view.freemarker.FreeMarkerView#setEncoding
 	 * @see org.springframework.web.servlet.view.freemarker.FreeMarkerView#setContentType
@@ -155,6 +157,18 @@ public void setDefaultEncoding(String defaultEncoding) {
 		this.defaultEncoding = defaultEncoding;
 	}
 
+	/**
+	 * Set the default encoding for the FreeMarker {@link Configuration}, which
+	 * is used to decode byte sequences to character sequences when reading template
+	 * files.
+	 * <p>See {@link #setDefaultEncoding(String)} for details.
+	 * @since 6.2
+	 * @see java.nio.charset.StandardCharsets
+	 */
+	public void setDefaultEncoding(Charset defaultEncoding) {
+		setDefaultEncoding(defaultEncoding.name());
+	}
+
 	/**
 	 * Set a List of {@link TemplateLoader TemplateLoaders} that will be used to
 	 * search for templates.

spring-webflux/src/main/java/org/springframework/web/reactive/result/view/freemarker/FreeMarkerConfigurer.java

@@ -17,6 +17,7 @@
 package org.springframework.web.reactive.result.view.freemarker;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.List;
 
 import freemarker.cache.ClassTemplateLoader;
@@ -68,7 +69,7 @@ public class FreeMarkerConfigurer extends FreeMarkerConfigurationFactory
 
 
 	public FreeMarkerConfigurer() {
-		setDefaultEncoding("UTF-8");
+		setDefaultEncoding(StandardCharsets.UTF_8);
 	}
 
 

spring-webflux/src/main/java/org/springframework/web/reactive/result/view/freemarker/FreeMarkerView.java

@@ -167,12 +167,24 @@ protected Configuration obtainConfiguration() {
 	 * process. See the note in the {@linkplain FreeMarkerView class-level
 	 * documentation} for details.
 	 * @see freemarker.template.Configuration#setDefaultEncoding
+	 * @see #setEncoding(Charset)
 	 * @see #getEncoding()
 	 */
 	public void setEncoding(@Nullable String encoding) {
 		this.encoding = encoding;
 	}
 
+	/**
+	 * Set the encoding used to decode byte sequences to character sequences when
+	 * reading the FreeMarker template file for this view.
+	 * <p>See {@link #setEncoding(String)} for details.
+	 * @since 6.2
+	 * @see java.nio.charset.StandardCharsets
+	 */
+	public void setEncoding(@Nullable Charset encoding) {
+		setEncoding(encoding != null ? encoding.name() : null);
+	}
+
 	/**
 	 * Get the encoding used to decode byte sequences to character sequences
 	 * when reading the FreeMarker template file for this view, or {@code null}
@@ -364,7 +376,9 @@ protected ObjectWrapper getObjectWrapper() {
 	}
 
 	/**
-	 * Get the FreeMarker template for the given locale, to be rendered by this view.
+	 * Retrieve the FreeMarker {@link Template} to be rendered by this view, for
+	 * the specified locale and using the {@linkplain #setEncoding(String) configured
+	 * encoding} if set.
 	 * <p>By default, the template specified by the "url" bean property will be retrieved.
 	 * @param locale the current locale
 	 * @return the FreeMarker template to render
@@ -379,7 +393,9 @@ protected Template getTemplate(Locale locale) throws IOException {
 	}
 
 	/**
-	 * Retrieve the FreeMarker template for the given locale, to be rendered by this view.
+	 * Retrieve the FreeMarker {@link Template} to be rendered by this view, for
+	 * the specified locale and using the {@linkplain #setEncoding(String) configured
+	 * encoding} if set.
 	 * <p>By default, the template specified by the "url" bean property will be retrieved,
 	 * and the returned mono will subscribe on the
 	 * {@linkplain Schedulers#boundedElastic() bounded elastic scheduler} as template

spring-webflux/src/test/java/org/springframework/web/reactive/config/WebFluxViewResolutionIntegrationTests.java

@@ -135,7 +135,7 @@ public void configureViewResolvers(ViewResolverRegistry registry) {
 			public FreeMarkerConfigurer freeMarkerConfigurer() {
 				FreeMarkerConfigurer configurer = new FreeMarkerConfigurer();
 				configurer.setPreTemplateLoaders(classTemplateLoader);
-				configurer.setDefaultEncoding(UTF_8.name());
+				configurer.setDefaultEncoding(UTF_8);
 				return configurer;
 			}
 		}
@@ -158,7 +158,7 @@ public void configureViewResolvers(ViewResolverRegistry registry) {
 			public FreeMarkerConfigurer freeMarkerConfigurer() {
 				FreeMarkerConfigurer configurer = new FreeMarkerConfigurer();
 				configurer.setPreTemplateLoaders(classTemplateLoader);
-				configurer.setDefaultEncoding(ISO_8859_1.name());
+				configurer.setDefaultEncoding(ISO_8859_1);
 				return configurer;
 			}
 

spring-webmvc/src/main/java/org/springframework/web/servlet/view/freemarker/FreeMarkerView.java

@@ -18,6 +18,7 @@
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.nio.charset.Charset;
 import java.util.Locale;
 import java.util.Map;
 
@@ -115,13 +116,25 @@ public class FreeMarkerView extends AbstractTemplateView {
 	 * process. See the note in the {@linkplain FreeMarkerView class-level
 	 * documentation} for details.
 	 * @see freemarker.template.Configuration#setDefaultEncoding
+	 * @see #setEncoding(Charset)
 	 * @see #getEncoding()
 	 * @see #setContentType(String)
 	 */
 	public void setEncoding(@Nullable String encoding) {
 		this.encoding = encoding;
 	}
 
+	/**
+	 * Set the encoding used to decode byte sequences to character sequences when
+	 * reading the FreeMarker template file for this view.
+	 * <p>See {@link #setEncoding(String)} for details.
+	 * @since 6.2
+	 * @see java.nio.charset.StandardCharsets
+	 */
+	public void setEncoding(@Nullable Charset encoding) {
+		setEncoding(encoding != null ? encoding.name() : null);
+	}
+
 	/**
 	 * Get the encoding used to decode byte sequences to character sequences
 	 * when reading the FreeMarker template file for this view, or {@code null}
@@ -316,10 +329,10 @@ protected SimpleHash buildTemplateModel(Map<String, Object> model, HttpServletRe
 	}
 
 	/**
-	 * Retrieve the FreeMarker {@link Template} for the given locale, to be
-	 * rendered by this view.
-	 * <p>By default, the template specified by the "url" bean property
-	 * will be retrieved.
+	 * Retrieve the FreeMarker {@link Template} to be rendered by this view, for
+	 * the specified locale and using the {@linkplain #setEncoding(String) configured
+	 * encoding} if set.
+	 * <p>By default, the template specified by the "url" bean property will be retrieved.
 	 * @param locale the current locale
 	 * @return the FreeMarker {@code Template} to render
 	 * @throws IOException if the template file could not be retrieved
@@ -333,8 +346,9 @@ protected Template getTemplate(Locale locale) throws IOException {
 	}
 
 	/**
-	 * Retrieve the FreeMarker {@link Template} for the specified name and locale,
-	 * using the {@linkplain #setEncoding(String) configured encoding} if set.
+	 * Retrieve the FreeMarker {@link Template} to be rendered by this view, for
+	 * the specified name and locale and using the {@linkplain #setEncoding(String)
+	 * configured encoding} if set.
 	 * <p>Can be called by subclasses to retrieve a specific template,
 	 * for example to render multiple templates into a single view.
 	 * @param name the file name of the desired template

spring-webmvc/src/test/java/org/springframework/web/servlet/config/annotation/ViewResolutionIntegrationTests.java

@@ -16,8 +16,6 @@
 
 package org.springframework.web.servlet.config.annotation;
 
-import java.nio.charset.StandardCharsets;
-
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
@@ -37,6 +35,7 @@
 import org.springframework.web.testfixture.servlet.MockServletConfig;
 import org.springframework.web.testfixture.servlet.MockServletContext;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatRuntimeException;
 
@@ -165,7 +164,7 @@ public void configureViewResolvers(ViewResolverRegistry registry) {
 			public FreeMarkerConfigurer freeMarkerConfigurer() {
 				FreeMarkerConfigurer configurer = new FreeMarkerConfigurer();
 				configurer.setTemplateLoaderPath("/WEB-INF/");
-				configurer.setDefaultEncoding(StandardCharsets.UTF_8.name());
+				configurer.setDefaultEncoding(UTF_8);
 				return configurer;
 			}
 		}
@@ -184,7 +183,7 @@ public FreeMarkerViewResolver freeMarkerViewResolver() {
 			public FreeMarkerConfigurer freeMarkerConfigurer() {
 				FreeMarkerConfigurer configurer = new FreeMarkerConfigurer();
 				configurer.setTemplateLoaderPath("/WEB-INF/");
-				configurer.setDefaultEncoding(StandardCharsets.UTF_8.name());
+				configurer.setDefaultEncoding(UTF_8);
 				return configurer;
 			}
 		}