Spring Boot RestTemboard ResourceAccessException：POST请求上的I/O错误无法响应

Question

我使用Spring Boot，在保持与第三方REST服务的长期连接的同时，遇到了以下问题：

org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://localhost:5000/products/10": localhost:5000 failed to respond; nested exception is org.apache.http.NoHttpResponseException: localhost:5000 failed to respond
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:732)
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:680)
    at org.springframework.web.client.RestTemplate.postForObject(RestTemplate.java:435)
    at com.example.pipeline.domain.service.nlp.NLPService.getDocumentsInfoNew(NLPService.java:42)
    at com.example.pipeline.domain.batch.steps.NLPTasklet.execute(NLPTasklet.java:170)
    at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:406)
    at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:330)
    at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140)
    at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:272)
    at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:81)
    at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:375)
    at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215)
    at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:145)
    at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:257)
    at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:200)
    at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:148)
    at org.springframework.batch.core.job.AbstractJob.handleStep(AbstractJob.java:394)
    at org.springframework.batch.core.job.SimpleJob.doExecute(SimpleJob.java:135)
    at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:308)
    at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:141)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.http.NoHttpResponseException: localhost:5000 failed to respond
    at org.apache.http.impl.conn.DefaultHttpRespons

此服务可以在返回结果之前将连接保持一个小时或更长时间。

我的RestTemplate配置如下所示：

public static RestTemplate createRestTemplate(int connectionTimeoutMs, int readTimeoutMs, ObjectMapper objectMapper) {

        HttpComponentsClientHttpRequestFactory httpRequestFactory = new HttpComponentsClientHttpRequestFactory(HttpClients.createDefault());
        httpRequestFactory.setConnectTimeout(connectionTimeoutMs);
        httpRequestFactory.setReadTimeout(readTimeoutMs);

        RestTemplate restTemplate = new RestTemplate(httpRequestFactory);
        List<ClientHttpRequestInterceptor> interceptors = new ArrayList<ClientHttpRequestInterceptor>();
        interceptors.add(new LoggingRequestInterceptor());
        restTemplate.setInterceptors(interceptors);
        restTemplate.setRequestFactory(new BufferingClientHttpRequestFactory(httpRequestFactory));
        MappingJackson2HttpMessageConverter messageConverter = restTemplate.getMessageConverters().stream().filter(MappingJackson2HttpMessageConverter.class::isInstance)
                .map(MappingJackson2HttpMessageConverter.class::cast).findFirst().orElseThrow(() -> new RuntimeException("MappingJackson2HttpMessageConverter not found"));
        messageConverter.setObjectMapper(objectMapper);

        restTemplate.getMessageConverters().stream().filter(StringHttpMessageConverter.class::isInstance).map(StringHttpMessageConverter.class::cast).forEach(a -> {
            a.setWriteAcceptCharset(false);
            a.setDefaultCharset(StandardCharsets.UTF_8);
        });

        return restTemplate;
    }

}

RestTemplate restTemplate = HttpUtils.createRestTemplate(60 * 1000, 3 * 60 * 60 * 1000, objectMapper);

我能做些什么来修复我这边的问题吗，或者这是http://localhost:5000服务端的纯问题，应该在那里修复？

Answer 1

最后，我提出了以下RestTempleat配置：

public class HttpUtils {

    static final Logger LOGGER = LoggerFactory.getLogger(HttpUtils.class);

    private static final int HTTP_CLIENT_RETRY_COUNT = 3;

    private static final int MAXIMUM_TOTAL_CONNECTION = 10;
    private static final int MAXIMUM_CONNECTION_PER_ROUTE = 5;
    private static final int CONNECTION_VALIDATE_AFTER_INACTIVITY_MS = 10 * 1000;

    public static RestTemplate createRestTemplate(int connectionTimeoutMs, int readTimeoutMs, ObjectMapper objectMapper) {

        HttpClientBuilder clientBuilder = HttpClients.custom();

        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();

        // Set the maximum number of total open connections.
        connectionManager.setMaxTotal(MAXIMUM_TOTAL_CONNECTION);
        // Set the maximum number of concurrent connections per route, which is 2 by default.
        connectionManager.setDefaultMaxPerRoute(MAXIMUM_CONNECTION_PER_ROUTE);

        connectionManager.setValidateAfterInactivity(CONNECTION_VALIDATE_AFTER_INACTIVITY_MS);

        clientBuilder.setConnectionManager(connectionManager);

        clientBuilder.setRetryHandler(new DefaultHttpRequestRetryHandler(HTTP_CLIENT_RETRY_COUNT, true, new ArrayList<>()) {

            @Override
            public boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
                LOGGER.info("Retry request, execution count: {}, exception: {}", executionCount, exception);
                return super.retryRequest(exception, executionCount, context);
            }

        });

        HttpComponentsClientHttpRequestFactory httpRequestFactory = new HttpComponentsClientHttpRequestFactory(clientBuilder.build());
        httpRequestFactory.setConnectTimeout(connectionTimeoutMs);
        httpRequestFactory.setConnectionRequestTimeout(readTimeoutMs);
        httpRequestFactory.setReadTimeout(readTimeoutMs);

        RestTemplate restTemplate = new RestTemplate(httpRequestFactory);
        List<ClientHttpRequestInterceptor> interceptors = new ArrayList<ClientHttpRequestInterceptor>();
        interceptors.add(new LoggingRequestInterceptor());
        restTemplate.setInterceptors(interceptors);
        restTemplate.setRequestFactory(new BufferingClientHttpRequestFactory(httpRequestFactory));

        MappingJackson2HttpMessageConverter messageConverter = restTemplate.getMessageConverters().stream().filter(MappingJackson2HttpMessageConverter.class::isInstance)
                .map(MappingJackson2HttpMessageConverter.class::cast).findFirst().orElseThrow(() -> new RuntimeException("MappingJackson2HttpMessageConverter not found"));
        messageConverter.setObjectMapper(objectMapper);

        restTemplate.getMessageConverters().stream().filter(StringHttpMessageConverter.class::isInstance).map(StringHttpMessageConverter.class::cast).forEach(a -> {
            a.setWriteAcceptCharset(false);
            a.setDefaultCharset(StandardCharsets.UTF_8);
        });

        return restTemplate;
    }

}

public class LoggingRequestInterceptor implements ClientHttpRequestInterceptor {

    private static final Logger LOGGER = LoggerFactory.getLogger(LoggingRequestInterceptor.class);

    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
    traceRequest(request, body);
    ClientHttpResponse response = execution.execute(request, body);
    traceResponse(response);
    return response;
    }

    private void traceRequest(HttpRequest request, byte[] body) throws IOException {
    LOGGER.debug("===========================request begin================================================");
    LOGGER.debug("URI         : {}", request.getURI());
    LOGGER.debug("Method      : {}", request.getMethod());
    LOGGER.debug("Headers     : {}", request.getHeaders());
    LOGGER.debug("Request body: {}", new String(body, "UTF-8"));
    LOGGER.debug("==========================request end================================================");
    }

    private void traceResponse(ClientHttpResponse response) throws IOException {
    StringBuilder inputStringBuilder = new StringBuilder();
    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(response.getBody(), "UTF-8"));
    String line = bufferedReader.readLine();
    while (line != null) {
        inputStringBuilder.append(line);
        inputStringBuilder.append('\n');
        line = bufferedReader.readLine();
    }
    LOGGER.debug("============================response begin==========================================");
    LOGGER.debug("Status code  : {}", response.getStatusCode());
    LOGGER.debug("Status text  : {}", response.getStatusText());
    LOGGER.debug("Headers      : {}", response.getHeaders());
    LOGGER.debug("Response body: {}", inputStringBuilder.toString());
    LOGGER.debug("=======================response end=================================================");
    }
}