http client遭遇Connection reset问题，以及解决方法

最新推荐文章于 2025-07-28 09:26:41 发布

lcx46

最新推荐文章于 2025-07-28 09:26:41 发布

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分类专栏：网络 Linux Java 文章标签： http client socket connection reset

本文链接：https://blog.youkuaiyun.com/lcx46/article/details/38984335

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博客讲述多线程连接池管理器发送HTTP请求时出现Connection reset异常。分析发现客户端有CLOSE_WAIT状态的socket连接，服务端有FIN_WAIT2状态连接，是服务端达到keepalive超时阈值主动断连。指出http client有重发机制却未成功，最后提出不使用httpclient重发机制，自己实现的解决办法。

客户端使用200个线程往服务器端发送数据，每次数据量约100K.

发送的时候使用了多线程连接池管理器

private MultiThreadedHttpConnectionManager connectionManager = new MultiThreadedHttpConnectionManager();
private HttpClient httpClient = new HttpClient(connectionManager);


httpClient.getHttpConnectionManager().getParams()
.setDefaultMaxConnectionsPerHost(WORKER_COUNT * 2);
httpClient.getHttpConnectionManager().getParams()
.setMaxTotalConnections(WORKER_COUNT * 5);
httpClient.getHttpConnectionManager().getParams().setSoTimeout(0);
httpClient.getHttpConnectionManager().getParams()
.setStaleCheckingEnabled(true);

<span style="font-family: Arial, Helvetica, sans-serif;">// 使用DefaultHttpMethodRetryHandler是希望在发送失败后能够自动重新发送</span>

<span style="font-family: Arial, Helvetica, sans-serif;">httpClient.getHttpConnectionManager().getParams()</span>

.setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler());

结果在实际的运行过程中发现不少的异常，导致数据没有发送成功：

[INFO ] 2014-08-31 13:00:35,804 -xxx.http.HttpMessageManager -430870 [pool-2-thread-126] INFO xxx.http.HttpMessageManager - io exception when send http.
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:168)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
at org.apache.commons.httpclient.HttpParser.readRawLine(Unknown Source)
at org.apache.commons.httpclient.HttpParser.readLine(Unknown Source)
at org.apache.commons.httpclient.HttpConnection.readLine(Unknown Source)
at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$HttpConnectionAdapter.readLine(Unknown Source)
at org.apache.commons.httpclient.HttpMethodBase.readStatusLine(Unknown Source)
at org.apache.commons.httpclient.HttpMethodBase.readResponse(Unknown Source)
at org.apache.commons.httpclient.HttpMethodBase.execute(Unknown Source)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(Unknown Source)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(Unknown Source)
at org.apache.commons.httpclient.HttpClient.executeMethod(Unknown Source)
at org.apache.commons.httpclient.HttpClient.executeMethod(Unknown Source)
at xxx.http.HttpMessageManager$MessageSendWorker.sendHttp(HttpMessageManager.java:308)
at xxx.http.HttpMessageManager$MessageSendWorker.run(HttpMessageManager.java:253)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
[ERROR] 2014-08-31 13:00:35,805 - xxx.http.HttpMessageManager -430871 [pool-2-thread-126] ERROR xxx.http.HttpMessageManager - send http fail after retry 3 times, url=http://10.10.10.10/metrics/put

加粗部分的日志是我自己打印的，因为DefaultHttpMethodRetryHandler在发送失败时会重试3次。

分析发现，通过netstat -an命令查看，客户端会出现几十个CLOSE_WAIT状态的socket连接，server端会出现一些FIN_WAIT2状态的连接，很明显server端主动发起了断连。查看server端的keepalive超时设置为15000毫秒，达到了此阈值时，就会强制关闭连接。

server端断连是一个正常的操作，关键是http client端不是有重发机制吗？所以不应该最后没有发送成功呀

http Client下多个线程共享connet连接池，每次发送时从池中获取一个连接：

    public void executeMethod(final HttpMethod method) throws IOException, HttpException {
        if (method == null) {
            throw new IllegalArgumentException("Method may not be null");
        }
        // Link all parameter collections to form the hierarchy:
        // Global -> HttpClient -> HostConfiguration -> HttpMethod
        this.hostConfiguration.getParams().setDefaults(this.params);
        method.getParams().setDefaults(this.hostConfiguration.getParams());
        
        // Generate default request headers
        Collection defaults = (Collection)this.hostConfiguration.getParams().
            getParameter(HostParams.DEFAULT_HEADERS);
        if (defaults != null) {
            Iterator i = defaults.iterator();
            while (i.hasNext()) {
                method.addRequestHeader((Header)i.next());
            }
        }
        
        try {
            int maxRedirects = this.params.getIntParameter(HttpClientParams.MAX_REDIRECTS, 100);


            for (int redirectCount = 0;;) {


                // make sure the connection we have is appropriate
                if (this.conn != null && !hostConfiguration.hostEquals(this.conn)) {
                    this.conn.setLocked(false);
                    this.conn.releaseConnection();
                    this.conn = null;
                }
        
                // get a connection, if we need one
                if (this.conn == null) {
                    <strong>this.conn = connectionManager.getConnectionWithTimeout(
                        hostConfiguration,
                        this.params.getConnectionManagerTimeout() 
                    );
                    this.conn.setLocked(true);
                    if (this.params.isAuthenticationPreemptive()
                     || this.state.isAuthenticationPreemptive()) 
                    {
                        LOG.debug("Preemptively sending default basic credentials");
                        method.getHostAuthState().setPreemptive();
                        method.getHostAuthState().setAuthAttempted(true);
                        if (this.conn.isProxied() && !this.conn.isSecure()) {
                            method.getProxyAuthState().setPreemptive();
                            method.getProxyAuthState().setAuthAttempted(true);
                        }
                    }</strong>
                }
                authenticate(method);
                <strong>executeWithRetry(method);</strong>
                if (this.connectMethod != null) {
                    fakeResponse(method);
                    break;
                }
                
                。。。。。


            } //end of retry loop
        } finally {
            if (this.conn != null) {
                this.conn.setLocked(false);
            }
            // If the response has been fully processed, return the connection
            // to the pool.  Use this flag, rather than other tests (like
            // responseStream == null), as subclasses, might reset the stream,
            // for example, reading the entire response into a file and then
            // setting the file as the stream.
            if (
                (releaseConnection || method.getResponseBodyAsStream() == null) 
                && this.conn != null
            ) {
                this.conn.releaseConnection();
            }
        }


    }

    private void executeWithRetry(final HttpMethod method) 
        throws IOException, HttpException {
        
        /** How many times did this transparently handle a recoverable exception? */
        int execCount = 0;
        // loop until the method is successfully processed, the retryHandler 
        // returns false or a non-recoverable exception is thrown
        try {
            while (true) {
                execCount++;
                try {


                    if (LOG.isTraceEnabled()) {
                        LOG.trace("Attempt number " + execCount + " to process request");
                    }
                    if (this.conn.getParams().isStaleCheckingEnabled()) {
                        this.conn.closeIfStale();
                    }
                    if (!this.conn.isOpen()) {
                        // this connection must be opened before it can be used
                        // This has nothing to do with opening a secure tunnel
                        this.conn.open();
                        if (this.conn.isProxied() && this.conn.isSecure() 
                        && !(method instanceof ConnectMethod)) {
                            // we need to create a secure tunnel before we can execute the real method
                            if (!executeConnect()) {
                                // abort, the connect method failed
                                return;
                            }
                        }
                    }
                    applyConnectionParams(method);                    
                    method.execute(state, this.conn);
                    break;
                } catch (HttpException e) {
                    // filter out protocol exceptions which cannot be recovered from
                    throw e;
                } catch (IOException e) {
                    LOG.debug("Closing the connection.");
                    this.conn.close();
                    。。。。
<strong>                    // ========================================
                    HttpMethodRetryHandler handler = 
                        (HttpMethodRetryHandler)method.getParams().getParameter(
                                HttpMethodParams.RETRY_HANDLER);</strong>
                    if (handler == null) {
                        handler = new DefaultHttpMethodRetryHandler();
                    }
                   <strong> if (!handler.retryMethod(method, e, execCount)) {</strong>
                        LOG.debug("Method retry handler returned false. "
                                + "Automatic recovery will not be attempted");
                        throw e;
                    }
                    。。。。
                }
            }
        } catch (IOException e) {
            if (this.conn.isOpen()) {
                LOG.debug("Closing the connection.");
                this.conn.close();
            }
            releaseConnection = true;
            throw e;
        } catch (RuntimeException e) {
            if (this.conn.isOpen()) {
                LOG.debug("Closing the connection.");
                this.conn.close();
            }
            releaseConnection = true;
            throw e;
        }
    }

    public boolean retryMethod(
        final HttpMethod method, 
        final IOException exception, 
        int executionCount) {
        if (method == null) {
            throw new IllegalArgumentException("HTTP method may not be null");
        }
        if (exception == null) {
            throw new IllegalArgumentException("Exception parameter may not be null");
        }
        // HttpMethod interface is the WORST thing ever done to HttpClient
        if (method instanceof HttpMethodBase) {

<strong>            // 此处判断如果连接异常，则不重发
            if (((HttpMethodBase)method).isAborted()) {
                return false;
            }</strong>
        }
        。。。。。
        return false;
    }

一直以为连接异常时也会重发，当server端主动断开时，client会根据StaleCheckingEnabled的值检测连接是否正常，如果正常才发送，发送异常时会重发。今天才发现http client的重发机制也是有限制的，如果网络异常退出，就不会重发，而是直接抛出异常。

解决办法：

不适用httpclient的重发机制，自己搞一个：

// 重试3次
int retry = 0;
do {
try {
int status = httpClient.executeMethod(postMethod);

if (HttpStatus.SC_OK == status) {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("send http success, url=" + url
+ ", content=" + message);
}
}else {
String rsp = HttpUtils
.getInputStreamAsString(postMethod
.getResponseBodyAsStream());
LOGGER.error("send http fail, status is: " + status
+ ", response is: " + rsp);
}
return;
} catch (HttpException e) {
postMethod.abort();
LOGGER.info("http exception when send http.", e);
} catch (IOException e) {
postMethod.abort();
LOGGER.info("io exception when send http.", e);
} finally {
postMethod.releaseConnection();
}
LOGGER.info("send http fail, retry:" + retry);
} while (++retry < 3);
// 如果到了第3次还未发送成功，则记录日志
LOGGER.error("send http fail after retry 3 times, url=" + url);