Customize RestTemplateBuilder

Allow customization of RestTemplateBuilder when created by RestTemplateAutoConfiguration.

Author: bedla

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/client/RestTemplateAutoConfigurationTests.java

@@ -47,10 +47,10 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.BDDMockito.doThrow;
 import static org.mockito.BDDMockito.given;
-import static org.mockito.Mockito.doThrow;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.verify;
+import static org.mockito.BDDMockito.mock;
+import static org.mockito.BDDMockito.verify;
 
 /**
  * Tests for {@link RestTemplateAutoConfiguration}
@@ -164,24 +164,21 @@ void whenReactiveWebApplicationRestTemplateBuilderIsNotConfigured() {
 
 	@Test
 	void customizerShouldCustomizeBuilder() {
-		contextRunner.withUserConfiguration(RestTemplateBuilderCustomizerConfig.class)
-				.run((context) -> {
-					assertThatThrownBy(() -> context.getBean(RestTemplateBuilder.class).build())
-							.isInstanceOf(IllegalStateException.class)
-							.hasMessageContaining("customized builder");
-				});
+		this.contextRunner.withUserConfiguration(RestTemplateBuilderCustomizerConfig.class).run((context) ->
+			assertThatThrownBy(() -> context.getBean(RestTemplateBuilder.class).build())
+					.isInstanceOf(IllegalStateException.class).hasMessageContaining("customized builder")
+		);
 	}
 
 	@Test
 	void customizerShouldReturnInstanceNotANull() {
-		contextRunner.withUserConfiguration(RestTemplateBuilderCustomizerReturnsNullConfig.class)
-				.run((context) -> {
-					assertThatThrownBy(() -> context.getBean(RestTemplateBuilder.class).build())
-							.isInstanceOf(BeanCreationException.class)
-							.hasMessageContaining("Error creating bean with name 'restTemplateBuilder'")
-							.hasRootCauseInstanceOf(IllegalArgumentException.class)
-							.hasRootCauseMessage("RestTemplateBuilderCustomizer returned null builder");
-				});
+		this.contextRunner.withUserConfiguration(RestTemplateBuilderCustomizerReturnsNullConfig.class).run((context) ->
+			assertThatThrownBy(() -> context.getBean(RestTemplateBuilder.class).build())
+					.isInstanceOf(BeanCreationException.class)
+					.hasMessageContaining("Error creating bean with name 'restTemplateBuilder'")
+					.hasRootCauseInstanceOf(IllegalArgumentException.class)
+					.hasRootCauseMessage("RestTemplateBuilderCustomizer returned null builder")
+		);
 	}
 
 	@Configuration(proxyBeanMethods = false)
@@ -261,21 +258,26 @@ static class CustomHttpMessageConverter extends StringHttpMessageConverter {
 
 	@Configuration(proxyBeanMethods = false)
 	static class RestTemplateBuilderCustomizerConfig {
+
 		@Bean
 		RestTemplateBuilderCustomizer restTemplateBuilderCustomizer() {
-			return oldBuilder -> {
+			return (oldBuilder) -> {
 				final RestTemplateBuilder builder = Mockito.spy(oldBuilder);
 				doThrow(new IllegalStateException("customized builder")).when(builder).build();
 				return builder;
 			};
 		}
+
 	}
 
 	@Configuration(proxyBeanMethods = false)
 	static class RestTemplateBuilderCustomizerReturnsNullConfig {
+
 		@Bean
 		RestTemplateBuilderCustomizer restTemplateBuilderCustomizer() {
-			return oldBuilder -> null;
+			return (oldBuilder) -> null;
 		}
+
 	}
+
 }

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/client/RestTemplateBuilderCustomizer.java

@@ -25,11 +25,12 @@
  */
 @FunctionalInterface
 public interface RestTemplateBuilderCustomizer {
+
 	/**
 	 * Callback to customize a {@link RestTemplateBuilder} instance.
-	 *
 	 * @param restTemplateBuilder the original builder to customize
 	 * @return customized builder instance
 	 */
 	RestTemplateBuilder customize(RestTemplateBuilder restTemplateBuilder);
+
 }