如何修复 SAP Cloud SDK 在应用程序启动期间抛出的 DestinationAccessException

Question

我想用 Spring 应用程序扩展 S/4HANA 云系统。可以无误地构建应用程序，也可以将其部署到 SAP Cloud Platform。当后端应用程序启动时，它会抛出一个错误。日志中的错误如下：

[.../WEB-INF/classes/com/sap/controllers/ExportController.class]: Unsatisfied dependency expressed through constructor parameter 0; 
nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'exportServiceImpl' defined in file [.../WEB-INF/classes/com/sap/services/ExportServiceImpl.class]: Unsatisfied dependency expressed through constructor parameter 0;
nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'adsService' defined in class path resource [com/sap/ads/service/ServiceConfiguration.class]: Bean instantiation via factory method failed;
nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.sap.ads.service.Service]: Factory method 'service' threw exception;
nested exception is com.sap.cloud.sdk.cloudplatform.connectivity.exception.DestinationAccessException: Failed to get ConnectivityConfiguration: no RequestContext available. Have you correctly configured a RequestContextServletFilter or have you wrapped your logic in a RequestContextExecutor when executing background tasks that are not triggered by a request?

之后，似乎错误发生在 ServiceConfiguration.class 和 DestinationAccessException 中。

我已经检查并包含了这个：

不幸的是，错误仍然存在。

以下是受影响部分的实施：

Service.class:

[...]
public interface Service {

    [...]

    public static final String DESTINATION_NAME = "myDestination";

    @RequestLine("POST /example/path")
    Response doSomething(Request myRequest);

}

ServiceConfiguration.class:

[...]
@Configuration
public class ServiceConfiguration {

    @Bean
    public Service service() {
        return Feign.builder()
                .encoder(new JacksonEncoder())
                .decoder(new JacksonDecoder())
                .client(DestinationHelper.getHttpClient(Service.DESTINATION_NAME))
            .target(Service.class, DestinationHelper.getUrl(service.DESTINATION_NAME));
    }

}

DestinationHelper.class:

[...]
public class DestinationHelper {

    /**
     * @return the URL of the destination with {@code destinationName}
     */
    public static String getUrl(String destinationName) {
        return DestinationAccessor
                .getDestination(destinationName)
                .getUri()
                .toString();
    }

    /**
     * @return an HTTP client preconfigured for the destination
     */
    public static ApacheHttpClient getHttpClient(final String destinationName) {
        return new ApacheHttpClient(HttpClientAccessor.getHttpClient(destinationName));
    }

}

服务实现中是否存在错误甚至缺失？根据错误日志，该服务似乎无法真正建立到目标的正确连接。

Answer 1

这里的问题是在申请 start-up 期间，还没有 RequestContext 可用。

解决问题的方法是将相关代码包装在 RequestContextExecutor 中，如下所示：

@Bean
public Service service() throws Exception {
    return new RequestContextExecutor().execute(() -> {
        return Feign.builder()
            .encoder(new JacksonEncoder())
            .decoder(new JacksonDecoder())
            .client(DestinationHelper.getHttpClient(Service.DESTINATION_NAME))
        .target(Service.class, DestinationHelper.getUrl(service.DESTINATION_NAME));
    };
}

如何修复 SAP Cloud SDK 在应用程序启动期间抛出的 DestinationAccessException

How to fix a DestinationAccessException thrown by the SAP Cloud SDK during application startup

java

sap-cloud-platform

sap-cloud-sdk

s4hana