refactor(spring-ai-mcp-server): enhance MCP server auto-configuration (spring-projects#2477)

- Update WebFlux and WebMvc server configurations to use ObjectProvider for ObjectMapper
- Add integration tests for MCP server auto-configurations
- Improve conditional checks for stdio configuration

Signed-off-by: Ahoo Wang <[email protected]>

Author: Ahoo-Wang

auto-configurations/mcp/spring-ai-autoconfigure-mcp-server/src/main/java/org/springframework/ai/mcp/server/autoconfigure/McpWebFluxServerAutoConfiguration.java

@@ -20,6 +20,7 @@
 import io.modelcontextprotocol.server.transport.WebFluxSseServerTransportProvider;
 import io.modelcontextprotocol.spec.McpServerTransportProvider;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
@@ -73,8 +74,10 @@ public class McpWebFluxServerAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	public WebFluxSseServerTransportProvider webFluxTransport(McpServerProperties serverProperties) {
-		return new WebFluxSseServerTransportProvider(new ObjectMapper(), serverProperties.getSseMessageEndpoint());
+	public WebFluxSseServerTransportProvider webFluxTransport(ObjectProvider<ObjectMapper> objectMapperProvider,
+			McpServerProperties serverProperties) {
+		ObjectMapper objectMapper = objectMapperProvider.getIfAvailable(ObjectMapper::new);
+		return new WebFluxSseServerTransportProvider(objectMapper, serverProperties.getSseMessageEndpoint());
 	}
 
 	// Router function for SSE transport used by Spring WebFlux to start an HTTP server.

auto-configurations/mcp/spring-ai-autoconfigure-mcp-server/src/main/java/org/springframework/ai/mcp/server/autoconfigure/McpWebMvcServerAutoConfiguration.java

@@ -20,6 +20,7 @@
 import io.modelcontextprotocol.server.transport.WebMvcSseServerTransportProvider;
 import io.modelcontextprotocol.spec.McpServerTransportProvider;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
@@ -68,8 +69,9 @@ public class McpWebMvcServerAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	public WebMvcSseServerTransportProvider webMvcSseServerTransportProvider(ObjectMapper objectMapper,
-			McpServerProperties serverProperties) {
+	public WebMvcSseServerTransportProvider webMvcSseServerTransportProvider(
+			ObjectProvider<ObjectMapper> objectMapperProvider, McpServerProperties serverProperties) {
+		ObjectMapper objectMapper = objectMapperProvider.getIfAvailable(ObjectMapper::new);
 		return new WebMvcSseServerTransportProvider(objectMapper, serverProperties.getSseMessageEndpoint());
 	}
 

auto-configurations/mcp/spring-ai-autoconfigure-mcp-server/src/test/java/org/springframework/ai/mcp/server/autoconfigure/McpWebFluxServerAutoConfigurationIT.java

@@ -0,0 +1,41 @@
+package org.springframework.ai.mcp.server.autoconfigure;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.modelcontextprotocol.server.transport.WebFluxSseServerTransportProvider;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.web.reactive.function.server.RouterFunction;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class McpWebFluxServerAutoConfigurationIT {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner().withConfiguration(
+			AutoConfigurations.of(McpWebFluxServerAutoConfiguration.class, McpServerAutoConfiguration.class));
+
+	@Test
+	void defaultConfiguration() {
+		this.contextRunner.run(context -> {
+			assertThat(context).hasSingleBean(WebFluxSseServerTransportProvider.class);
+			assertThat(context).hasSingleBean(RouterFunction.class);
+		});
+	}
+
+	@Test
+	void objectMapperConfiguration() {
+		this.contextRunner.withBean(ObjectMapper.class, ObjectMapper::new).run(context -> {
+			assertThat(context).hasSingleBean(WebFluxSseServerTransportProvider.class);
+			assertThat(context).hasSingleBean(RouterFunction.class);
+		});
+	}
+
+	@Test
+	void stdioEnabledConfiguration() {
+		this.contextRunner.withPropertyValues("spring.ai.mcp.server.stdio=true").run(context -> {
+			assertThat(context).doesNotHaveBean(WebFluxSseServerTransportProvider.class);
+		});
+	}
+
+}

auto-configurations/mcp/spring-ai-autoconfigure-mcp-server/src/test/java/org/springframework/ai/mcp/server/autoconfigure/McpWebMvcServerAutoConfigurationTest.java

@@ -0,0 +1,41 @@
+package org.springframework.ai.mcp.server.autoconfigure;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.modelcontextprotocol.server.transport.WebMvcSseServerTransportProvider;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.web.servlet.function.RouterFunction;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class McpWebMvcServerAutoConfigurationTest {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner().withConfiguration(
+			AutoConfigurations.of(McpWebMvcServerAutoConfiguration.class, McpServerAutoConfiguration.class));
+
+	@Test
+	void defaultConfiguration() {
+		this.contextRunner.run(context -> {
+			assertThat(context).hasSingleBean(WebMvcSseServerTransportProvider.class);
+			assertThat(context).hasSingleBean(RouterFunction.class);
+		});
+	}
+
+	@Test
+	void objectMapperConfiguration() {
+		this.contextRunner.withBean(ObjectMapper.class, ObjectMapper::new).run(context -> {
+			assertThat(context).hasSingleBean(WebMvcSseServerTransportProvider.class);
+			assertThat(context).hasSingleBean(RouterFunction.class);
+		});
+	}
+
+	@Test
+	void stdioEnabledConfiguration() {
+		this.contextRunner.withPropertyValues("spring.ai.mcp.server.stdio=true").run(context -> {
+			assertThat(context).doesNotHaveBean(WebMvcSseServerTransportProvider.class);
+		});
+	}
+
+}