openFeign服务之间调用保持请求头信息处理方式

openFeign服务间调用保持请求头信息处理

1、注意特殊情况，在定时任务或者内部之间调用，没有request的时候，不要处理直接返回。

2、在GET请求，参数确放在Body里面传递的情况，restTemplate是不认识的，所以这里要转化下处理，然后清空body数据

3、在请求过程中如果出现java.io.IOException: too many bytes written异常，请参考保持请求头造成请求头和content-length不一致

/**
 * 解决服务调用丢失请求头的问题
 * @author 大仙
 *
 */
@Component
public class FeignConfiguration implements RequestInterceptor{
    private final Logger logger = LoggerFactory.getLogger(getClass());

    @Autowired
    private ObjectMapper objectMapper;

    @Override
    public void apply(RequestTemplate template) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder
                .getRequestAttributes();
        // 注意: RequestContextHolder依赖于 ThreadLocal, 所以在hystrix的隔离策略为THREAD、MQ的消费者、定时任务调用feignClient时，此处应为null
        if (attributes == null) {
            return;
        }
        HttpServletRequest request = attributes.getRequest();
        Enumeration<String> headerNames = request.getHeaderNames();
        if (headerNames != null) {
            while (headerNames.hasMoreElements()) {
                String name = headerNames.nextElement();
                String values = request.getHeader(name);
                template.header(name, values);
            }
        }
        logger.info("保持请求头");
        //feign 不支持 GET 方法传 POJO, json body转query
        if (template.method().equals("GET") && template.requestBody().asBytes() != null) {
            try {
                JsonNode jsonNode = objectMapper.readTree(template.requestBody().asBytes());
                Request.Body.empty();

                Map<String, Collection<String>> queries = new HashMap<>();
                buildQuery(jsonNode, "", queries);
                template.queries(queries);
            } catch (IOException e) {
                //提示:根据实践项目情况处理此处异常，这里不做扩展。
                e.printStackTrace();
            }
        }
    }

    /**
     * 改造
     * @param jsonNode
     * @param path
     * @param queries
     */
    private void buildQuery(JsonNode jsonNode, String path, Map<String, Collection<String>> queries) {
        // 叶子节点
        if (!jsonNode.isContainerNode()) {
            if (jsonNode.isNull()) {
                return;
            }
            Collection<String> values = queries.get(path);
            if (null == values) {
                values = new ArrayList<>();
                queries.put(path, values);
            }
            values.add(jsonNode.asText());
            return;
        }
        // 数组节点
        if (jsonNode.isArray()) {
            Iterator<JsonNode> it = jsonNode.elements();
            while (it.hasNext()) {
                buildQuery(it.next(), path, queries);
            }
        } else {
            Iterator<Map.Entry<String, JsonNode>> it;
            it = jsonNode.fields();
            while (it.hasNext()) {
                Map.Entry<String, JsonNode> entry = it.next();
                if (StringUtils.hasText(path)) {
                    buildQuery(entry.getValue(), path + "." + entry.getKey(), queries);
                } else {
                    // 根节点
                    buildQuery(entry.getValue(), entry.getKey(), queries);
                }
            }
        }
    }
}

保持请求头造成请求头和content-length不一致

Request processin g failed； nested exception is feign.RetryableException: too many bytes written

2020-09-08 14:07:14.718 ERROR 16146 --- [io-12000-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processin
g failed; nested exception is feign.RetryableException: too many bytes written executing POST http://pay/wx/create] with root cause
java.io.IOException: too many bytes written
	at sun.net.www.protocol.http.HttpURLConnection$StreamingOutputStream.write(HttpURLConnection.java:3574) ~[na:1.8.0_212]
	at sun.net.www.protocol.http.HttpURLConnection$StreamingOutputStream.write(HttpURLConnection.java:3565) ~[na:1.8.0_212]
	at feign.Client$Default.convertAndSend(Client.java:181) ~[feign-core-10.4.0.jar!/:na]
	at feign.Client$Default.execute(Client.java:77) ~[feign-core-10.4.0.jar!/:na]
	at org.springframework.cloud.openfeign.ribbon.RetryableFeignLoadBalancer$1.doWithRetry(RetryableFeignLoadBalancer.java:114) ~[spring-cloud-openfeign-core-2.1.5.RELEASE.jar!/:2.1.5.RELEASE]
	at org.springframework.cloud.openfeign.ribbon.RetryableFeignLoadBalancer$1.doWithRetry(RetryableFeignLoadBalancer.java:94) ~[spring-cloud-openfeign-core-2.1.5.RELEASE.jar!/:2.1.5.RELEASE]
	at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:287) ~[spring-retry-1.2.5.RELEASE.jar!/:na]
	at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:180) ~[spring-retry-1.2.5.RELEASE.jar!/:na]
	at org.springframework.cloud.openfeign.ribbon.RetryableFeignLoadBalancer.execute(RetryableFeignLoadBalancer.java:94) ~[spring-cloud-openfeign-core-2.1.5.RELEASE.jar!/:2.1.5.RELEASE]
	at org.springframework.cloud.openfeign.ribbon.RetryableFeignLoadBalancer.execute(RetryableFeignLoadBalancer.java:54) ~[spring-cloud-openfeign-core-2.1.5.RELEASE.jar!/:2.1.5.RELEASE]
	at com.netflix.client.AbstractLoadBalancerAwareClient$1.call(AbstractLoadBalancerAwareClient.java:104) ~[ribbon-loadbalancer-2.3.0.jar!/:2.3.0]
	at com.netflix.loadbalancer.reactive.LoadBalancerCommand$3$1.call(LoadBalancerCommand.java:303) ~[ribbon-loadbalancer-2.3.0.jar!/:2.3.0]
	at com.netflix.loadbalancer.reactive.LoadBalancerCommand$3$1.call(LoadBalancerCommand.java:287) ~[ribbon-loadbalancer-2.3.0.jar!/:2.3.0]
	at rx.internal.util.ScalarSynchronousObservable$3.call(ScalarSynchronousObservable.java:231) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.util.ScalarSynchronousObservable$3.call(ScalarSynchronousObservable.java:228) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.Observable.unsafeSubscribe(Observable.java:10327) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OnSubscribeConcatMap$ConcatMapSubscriber.drain(OnSubscribeConcatMap.java:286) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OnSubscribeConcatMap$ConcatMapSubscriber.onNext(OnSubscribeConcatMap.java:144) ~[rxjava-1.3.8.jar!/:1.3.8]
	at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:185) ~[ribbon-loadbalancer-2.3.0.jar!/:2.3.0]
	at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180) ~[ribbon-loadbalancer-2.3.0.jar!/:2.3.0]
	at rx.Observable.unsafeSubscribe(Observable.java:10327) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.Observable.unsafeSubscribe(Observable.java:10327) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber$1.call(OperatorRetryWithPredicate.java:127) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.enqueue(TrampolineScheduler.java:73) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.schedule(TrampolineScheduler.java:52) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:79) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:45) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.util.ScalarSynchronousObservable$WeakSingleProducer.request(ScalarSynchronousObservable.java:276) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.Subscriber.setProducer(Subscriber.java:209) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:138) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:129) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.3.8.jar!/:1.3.8]
	at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.3.8.jar!/:1.3.8

原因是：body是跟Content-Length 有关系

复制的时候是所有头都复制的,可能导致Content-length长度跟body不一致. 所以只需要判断如果是Content-length就跳过

解决方式：更改复制逻辑

 while (headerNames.hasMoreElements()) {
                String name = headerNames.nextElement();
                // 跳过 content-length
                if (name.equals("content-length")){
                    continue;
                }
                String values = request.getHeader(name);
                template.header(name, values);
            }

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。