应用程序属性未注入ClientHttpRequestInterceptor中的私有变量

Question

我编写了一个ClientHttpRequestInterceptor实现，以自动将一些HttpHeader插入到来自Spring Boot服务的任何传出请求中。

我支持的头之一是指示发送此请求的源应用程序。为此，我将“spring.application.name”应用程序属性注入到私有变量中，并使用该私有变量设置HttpHeader。

public class ClientHeaderPropagationInterceptor implements ClientHttpRequestInterceptor {

    @Value("${spring.application.name}")
    private String appName;

    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
        log.debug("ClientHeaderPropagationInterceptor in action");

        // Set source header for traceability between microservices
        log.debug("Setting request source to {}", appName);
        requestHeaders.set("source", appName);

        return execution.execute(request, body);
    }
}

@Configuration
public class ApplicationConfig {

...
    @LoadBalanced
    @Bean(name = "loadBalancedRestTemplate")
    public RestTemplate getLoadBalancedRestTemplate(){
        RestTemplate restTemplate = new RestTemplate(customHttpRequestFactory());
        restTemplate.setErrorHandler(new CustomResponseHandler());
        restTemplate.getMessageConverters().add(0, new StringHttpMessageConverter(StandardCharsets.UTF_8));
        restTemplate.setInterceptors(Collections.singletonList(new ClientHeaderPropagationInterceptor()));
        return restTemplate;
    }
...
}

Answer 1

@value不适用于非托管spring bean。首先，您需要让它成为spring管理。尝试以下操作：

    @Bean
    public ClientHeaderPropagationInterceptor clientHeaderPropagationInterceptor() {
        return new ClientHeaderPropagationInterceptor();
    }

    @LoadBalanced
    @Bean(name = "loadBalancedRestTemplate")
    public RestTemplate getLoadBalancedRestTemplate(){
        RestTemplate restTemplate = new RestTemplate(customHttpRequestFactory());
        restTemplate.setErrorHandler(new CustomResponseHandler());
        restTemplate.getMessageConverters().add(0, new StringHttpMessageConverter(StandardCharsets.UTF_8));
        restTemplate.setInterceptors(Collections.singletonList(clientHeaderPropagationInterceptor()));
        return restTemplate;
    }