Use the configured charset, if any, in MustacheViewResolver

Closes gh-2670

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/MustacheAutoConfiguration.java

@@ -108,6 +108,7 @@ public class MustacheAutoConfiguration {
 			resolver.setCache(this.mustache.isCache());
 			resolver.setViewNames(this.mustache.getViewNames());
 			resolver.setContentType(this.mustache.getContentType());
+			resolver.setCharset(this.mustache.getCharset());
 			resolver.setCompiler(mustacheCompiler);
 			resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
 			return resolver;

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/web/MustacheViewResolver.java

@@ -34,12 +34,15 @@ import com.samskivert.mustache.Template;
  * Spring MVC {@link ViewResolver} for Mustache.
  *
  * @author Dave Syer
+ * @author Andy Wilkinson
  * @since 1.2.2
  */
 public class MustacheViewResolver extends UrlBasedViewResolver {
 
 	private Compiler compiler = Mustache.compiler();
 
+	private String charset;
+
 	public MustacheViewResolver() {
 		setViewClass(MustacheView.class);
 	}
@@ -51,6 +54,13 @@ public class MustacheViewResolver extends UrlBasedViewResolver {
 		this.compiler = compiler;
 	}
 
+	/**
+	 * @param charset the charset to set
+	 */
+	public void setCharset(String charset) {
+		this.charset = charset;
+	}
+
 	@Override
 	protected View loadView(String viewName, Locale locale) throws Exception {
 		Resource resource = resolveResource(viewName, locale);
@@ -64,7 +74,9 @@ public class MustacheViewResolver extends UrlBasedViewResolver {
 	}
 
 	private Template createTemplate(Resource resource) throws IOException {
-		return this.compiler.compile(new InputStreamReader(resource.getInputStream()));
+		return this.charset == null ? this.compiler.compile(new InputStreamReader(
+				resource.getInputStream())) : this.compiler
+				.compile(new InputStreamReader(resource.getInputStream(), this.charset));
 	}
 
 	private Resource resolveResource(String viewName, Locale locale) {