Add spring.*.enabled for MVC view resolvers

Since we use a composite ViewResolver glbally by default it can be
awkward to switch off the view technology that you have on the classpath
but aren't actually using.

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/freemarker/FreeMarkerAutoConfiguration.java

@@ -29,6 +29,7 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnNotWebApplication;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -134,6 +135,7 @@ public class FreeMarkerAutoConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean(name = "freeMarkerViewResolver")
+		@ConditionalOnProperty(name = "spring.freemarker.enabled", matchIfMissing = true)
 		public FreeMarkerViewResolver freeMarkerViewResolver() {
 			FreeMarkerViewResolver resolver = new FreeMarkerViewResolver();
 			this.properties.applyToViewResolver(resolver);

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/freemarker/FreeMarkerProperties.java

@@ -48,10 +48,23 @@ public class FreeMarkerProperties extends AbstractTemplateViewResolverProperties
 	 */
 	private String[] templateLoaderPath = new String[] { DEFAULT_TEMPLATE_LOADER_PATH };
 
+	/**
+	 * Switches off MVC view resolution if set to false (default true).
+	 */
+	private boolean enabled = true;
+
 	public FreeMarkerProperties() {
 		super(DEFAULT_PREFIX, DEFAULT_SUFFIX);
 	}
 
+	public boolean isEnabled() {
+		return this.enabled;
+	}
+
+	public void setEnabled(boolean enabled) {
+		this.enabled = enabled;
+	}
+
 	public Map<String, String> getSettings() {
 		return this.settings;
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfiguration.java

@@ -25,6 +25,7 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration;
 import org.springframework.boot.context.properties.ConfigurationProperties;
@@ -103,6 +104,7 @@ public class GroovyTemplateAutoConfiguration {
 	@ConditionalOnClass({ Servlet.class, LocaleContextHolder.class,
 			UrlBasedViewResolver.class })
 	@ConditionalOnWebApplication
+	@ConditionalOnProperty(name = "spring.groovy.template.enabled", matchIfMissing = true)
 	public static class GroovyWebConfiguration {
 
 		@Autowired

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateProperties.java

@@ -50,6 +50,19 @@ public class GroovyTemplateProperties extends AbstractViewResolverProperties {
 	 */
 	private Map<String, Object> configuration = new HashMap<String, Object>();
 
+	/**
+	 * Switches off MVC view resolution if set to false (default true).
+	 */
+	private boolean enabled = true;
+
+	public boolean isEnabled() {
+		return this.enabled;
+	}
+
+	public void setEnabled(boolean enabled) {
+		this.enabled = enabled;
+	}
+
 	public String getPrefix() {
 		return this.prefix;
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/thymeleaf/ThymeleafAutoConfiguration.java

@@ -29,6 +29,7 @@ import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -175,6 +176,7 @@ public class ThymeleafAutoConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean(name = "thymeleafViewResolver")
+		@ConditionalOnProperty(name = "spring.thymeleaf.enabled", matchIfMissing = true)
 		public ThymeleafViewResolver thymeleafViewResolver() {
 			ThymeleafViewResolver resolver = new ThymeleafViewResolver();
 			resolver.setTemplateEngine(this.templateEngine);

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/thymeleaf/ThymeleafProperties.java

@@ -76,6 +76,19 @@ public class ThymeleafProperties {
 	 */
 	private String[] excludedViewNames;
 
+	/**
+	 * Switches off MVC view resolution if set to false (default true).
+	 */
+	private boolean enabled = true;
+
+	public boolean isEnabled() {
+		return this.enabled;
+	}
+
+	public void setEnabled(boolean enabled) {
+		this.enabled = enabled;
+	}
+
 	public boolean isCheckTemplateLocation() {
 		return this.checkTemplateLocation;
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/velocity/VelocityAutoConfiguration.java

@@ -30,6 +30,7 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnNotWebApplication;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -124,6 +125,7 @@ public class VelocityAutoConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean(name = "velocityViewResolver")
+		@ConditionalOnProperty(name = "spring.velocity.enabled", matchIfMissing = true)
 		public VelocityViewResolver velocityViewResolver() {
 			VelocityViewResolver resolver = new VelocityViewResolver();
 			this.properties.applyToViewResolver(resolver);

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/velocity/VelocityProperties.java

@@ -71,10 +71,23 @@ public class VelocityProperties extends AbstractTemplateViewResolverProperties {
 	 */
 	private boolean preferFileSystemAccess = true;
 
+	/**
+	 * Switches off MVC view resolution if set to false (default true).
+	 */
+	private boolean enabled = true;
+
 	public VelocityProperties() {
 		super(DEFAULT_PREFIX, DEFAULT_SUFFIX);
 	}
 
+	public boolean isEnabled() {
+		return this.enabled;
+	}
+
+	public void setEnabled(boolean enabled) {
+		this.enabled = enabled;
+	}
+
 	public String getDateToolAttribute() {
 		return this.dateToolAttribute;
 	}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfigurationTests.java

@@ -38,6 +38,7 @@ import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.mock.web.MockServletContext;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
 import org.springframework.web.servlet.View;
+import org.springframework.web.servlet.ViewResolver;
 import org.springframework.web.servlet.support.RequestContext;
 import org.springframework.web.servlet.view.groovy.GroovyMarkupConfig;
 import org.springframework.web.servlet.view.groovy.GroovyMarkupViewResolver;
@@ -100,6 +101,15 @@ public class GroovyTemplateAutoConfigurationTests {
 		assertThat(response.getContentType(), equalTo("text/html;charset=UTF-8"));
 	}
 
+	@Test
+	public void disableViewResolution() throws Exception {
+		EnvironmentTestUtils.addEnvironment(this.context,
+				"spring.groovy.template.enabled:false");
+		registerAndRefreshContext();
+		assertThat(this.context.getBeanNamesForType(ViewResolver.class).length,
+				equalTo(0));
+	}
+
 	@Test
 	public void localeViewResolution() throws Exception {
 		registerAndRefreshContext();