java - httpclient4.5.4中如何释放PoolingHttpClientConnectionManager

Question

我在使用 httpclients 4.5.4 时遇到问题。当我关闭与连接相关的所有内容时，java GC 无法收集 PoolingHttpClientConnectionManager 对象。当应用程序运行大约 1 个月时，我遇到了 OOM 异常。我的代码与 https://hc.apache.org/httpcomponents-client-4.5.x/httpclient/examples/org/apache/http/examples/client/ClientConnectionRelease.java 中的示例相同。并且InternalHttpClient对象也不能被java GC收集。下面是我的代码，是否有任何对象保存这两个类的引用？

    import java.io.BufferedReader;
    import java.io.File;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.util.Map;

    import org.apache.http.HttpStatus;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.entity.ContentType;
    import org.apache.http.entity.mime.MultipartEntityBuilder;
    import org.apache.http.entity.mime.content.FileBody;
    import org.apache.http.entity.mime.content.StringBody;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;

    public class HttpUtil {

        private static Logger logger = LoggerFactory.getLogger(HttpUtil.class);

        /**
         * Http post请求
         */
        public static String doHttpPost(String postUrl, Map<String, String> headers,
                Map<String,String> params,String filePath) {
            try {
                CloseableHttpClient httpClient = HttpClients.createDefault();
                try {
                    HttpPost post = getHttpPost(postUrl, headers, params, filePath);
                    CloseableHttpResponse response = httpClient.execute(post);
                    try {
                        InputStream inputStream = null;
                        InputStreamReader inputStreamReader = null;
                        BufferedReader bufferedReader = null;
                        if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                            try {
                                inputStream = response.getEntity().getContent();
                                inputStreamReader = new InputStreamReader(inputStream);
                                bufferedReader = new BufferedReader(inputStreamReader);
                                return bufferedReader.readLine();
                            }catch (Exception e) {
                                logger.warn("do http post fail : ", e);
                            }finally {
                                if (bufferedReader != null) {
                                    logger.info("release bufferedReader: " + filePath);
                                    bufferedReader.close();
                                }
                                if (inputStreamReader != null) {
                                    logger.info("release inputStreamReader: " +filePath);
                                    inputStreamReader.close();
                                }
                                if (inputStream != null) {
                                    logger.info("release inputStream: " +filePath);
                                    inputStream.close();
                                }
                            }
                        }
                    } catch (Exception e) {
                        logger.warn("do http post fail: ", e);
                    } finally {
                        if (response != null) {
                            logger.info("release response: " + filePath);
                            response.close();
                        }
                        if (post != null) {
                            logger.info("release HttpPost: " + filePath);
                            post.releaseConnection();
                        }
                    }
                } catch (Exception e) {
                    logger.warn("do http post fail: ", e);
                } finally {
                    if (httpClient != null) {
                        logger.info("release httpClient: " + filePath);
                        httpClient.close();
                        logger.info("release connectionManager: " + filePath);
                        httpClient.getConnectionManager().shutdown();
                    }
                }
            } catch (Exception e) {
                logger.warn("do http post fail: ", e);
            }

            return "";
        }

        private static HttpPost getHttpPost(String postUrl, Map<String, String> headers,
                Map<String, String> params, String filePath) {
            HttpPost post = new HttpPost(postUrl);
            String[] headerKeys = headers.keySet().toArray(new String[headers.keySet().size()]);
            for (String key : headerKeys) {
                post.setHeader(key, headers.get(key));
            }

            FileBody fileBody = new FileBody(new File(filePath));
            MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
            multipartEntityBuilder.addPart("express_image", fileBody);

            String[] paramKeys = params.keySet().toArray(new String[params.keySet().size()]);
            for (String key : paramKeys) {
                StringBody valueBody = new StringBody(params.get(key), ContentType.TEXT_PLAIN);
                multipartEntityBuilder.addPart(key, valueBody);
            }

            post.setEntity(multipartEntityBuilder.build());
            return post;
        }

    }

Answer 1

我无法告诉你为什么内存不足，但我可以告诉你，这样做并不是一个好主意(尽管你使用了“推荐的方式”)。

我使用的是 4.5.3 版本中的 CloseableHttpClient 和 PoolingHttpClientConnectionManager，而且我从不关闭它们(它们都在单例中分配一次并用于所有请求)。我的应用程序目前运行大约一个月后每秒执行一个请求(不是很多)。

请注意，为每个连接创建一个新客户端与为每次旅行购买一辆新车一样高效。