httpclient异常"org.apache.http.conn.ConnectionPoolTimeoutException:超时等待连接"

Question

我正在尝试使用以下代码向我的服务器发送请求.总是在第3次请求时失败了.

import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.HttpVersion;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;

public class HttpClientTest {
    private HttpClient client;

    public HttpClientTest() {
        HttpParams params = new BasicHttpParams();
        params.setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 15000);  
        params.setParameter(CoreConnectionPNames.SO_TIMEOUT, 15000);

        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        HttpProtocolParams.setContentCharset(params, "utf-8");
        HttpProtocolParams.setUseExpectContinue(params, true);
        ThreadSafeClientConnManager cm = new ThreadSafeClientConnManager();
        cm.setMaxTotal(100);
        client = new DefaultHttpClient(cm, params);

        while (true) {
            HttpPost mPost = new HttpPost("http://myip/myservice");

            JSONObject json = new JSONObject();
            try {
                json.put("serialNumber", "abcd");
            } catch (JSONException e1) {
                e1.printStackTrace();
            }
            StringEntity s = null;
            try {
                s = new StringEntity(json.toString());
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }               
            s.setContentEncoding("UTF-8");
            s.setContentType("application/json");
            mPost.setEntity(s);

            JSONObject response = null;

            System.out.println("HttpClientTest ---> send post");
            HttpResponse mHttpResponse;
            try {
                mHttpResponse = client.execute(mPost);
                System.out.println("HttpClientTest  ---> get response");
                if(mHttpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
                    HttpEntity entity = mHttpResponse.getEntity(); 
                    ContentType contentType = ContentType.getOrDefault(entity);
                    Charset charset = contentType.getCharset();
                    response = new JSONObject(new JSONTokener(new InputStreamReader(entity.getContent(), charset)));

                    System.out.println("HttpClientTest ---> get result:" + response.toString());
                } else {
                    mPost.abort();
                    break;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        HttpClientTest t = new HttpClientTest();
    }
}

例外情况如下:

org.apache.http.conn.ConnectionPoolTimeoutException: Timeout waiting for connection
    at org.apache.http.impl.conn.tsccm.ConnPoolByRoute.getEntryBlocking(ConnPoolByRoute.java:417)
    at org.apache.http.impl.conn.tsccm.ConnPoolByRoute$1.getPoolEntry(ConnPoolByRoute.java:300)
    at org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager$1.getConnection(ThreadSafeClientConnManager.java:224)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:401)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:820)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:754)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:732)
    at com.i360r.client.takeaway.network.HttpClientTest.<init>(HttpClientTest.java:68)
    at com.i360r.client.takeaway.network.HttpClientTest.main(HttpClientTest.java:88)

Answer 1

我有同样的问题,我找到了修复.此超时是因为连接泄漏.在我的情况下,我正在使用httpDelete方法而不是消耗响应.而是检查响应的状态.

修复方法是,需要使用响应实体.为了确保正确释放系统资源,必须关闭与实体关联的内容流.

所以我使用 EntityUtils.consumeQuietly(response.getEntity());它确保实体内容被完全消耗,并且内容流(如果存在)被关闭.

Answer 2

我修好了!添加mPost.releaseConnection()的finally块.

 try {
 } catch (Exception e) {
 } finally {
  mPost.releaseConnection();
 }

请将包更新org.apache.httpcomponents到4.2.1

Answer 3

使用 aCloseableHttpClient代替HttpClient. 您将获得 aCloseableHttpResponse而不是HttpResponsewhich 支持close()。因此，当您完成响应后，只需关闭它即可，无需关闭连接。

CloseableHttpResponse response = closableHttpClient.execute(httpPost, context);

...用它做你需要做的事情：

response.close();

Answer 4

只需将行的内容放在try-with-resources中，然后使用CloseableHttpResponse而不是HttpResponse即可，如下所示：

try(final CloseableHttpResponse mHttpResponse = client.execute(mPost);)
{
 System.out.println("HttpClientTest  ---> get response");
 ....remainder code

mHttpResponse对象将自动为您使用并关闭

希望这可以帮助！