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java.lang.IllegalStateException: Connection pool shut down

时间:2018-05-15 18:29:59      阅读:11565      评论:0      收藏:0      [点我收藏+]

标签:连接超时   reference   prot   eval   rest   一句话   conf   eva   clear   

最近使用HttpClient 4.5 使用 CloseableHttpClient 发起连接后,使用CloseableHttpResponse 接受返回结果,结果就报错了,上网查了下,有位stackoverflow的大兄弟说,只要将:

 CloseableHttpClient httpClient    = HttpClients.createDefault();
改为:
CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(connManager).setConnectionManagerShared(true).build();

就可以整正常执行了,于是,用之,果然不报错了,但是为什么呢?以下是大兄弟的原文解释:

I was having a similar error when I came across this thread and this seemed to fix the issue for me. I know this is an old question, but adding thoughts for others for future reference.

I‘m not 100% sure as to why this fix works as the documentation around this is pretty awful. It was a lot of trial and error with what I was testing to get to this solution. From what I can

gather though, this fix works because it is then using a shared connection pool in the background, which means that connections remain open for use.

关键是最后一句话:大概意思是,后台使用一个共享连接池,供剩下打开的连接去使用

 

原文地址:https://stackoverflow.com/questions/41744410/executorservice-performing-rest-requests

感谢下这位大兄弟

 

apache 官方的建议是,创建连接池,并为每一个接口URL分配一个线程,去执行,还给出了许多高并发访问的编码技巧

原文:https://hc.apache.org/httpcomponents-client-ga/tutorial/html/connmgmt.html

那么,使用HttpClient 4.5连接池的正确姿势是什么呢?

原作者地址:https://my.oschina.net/xlj44400/blog/711341

 

摘要: HttpClient 是 Apache Jakarta Common 下的子项目,可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包,并且它支持 HTTP 协议最新的版本和建议

HttpClient简介

HttpClient 是 Apache Jakarta Common 下的子项目,可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包,并且它支持 HTTP 协议最新的版本和建议。HttpClient支持的功能如下:

  • 支持Http0.9、Http1.0和Http1.1协议。
  • 实现了Http全部的方法(GET,POST,PUT,HEAD 等)。
  • 支持HTTPS协议。
  • 支持代理服务器。
  • 提供安全认证方案。
  • 提供连接池以便重用连接。
  • 连接管理器支持多线程应用。支持设置最大连接数,同时支持设置每个主机的最大连接数,发现并关闭过期的连接。
  • 在http1.0和http1.1中利用KeepAlive保持长连接。

以前是commons-httpclient,后面被Apache HttpComponents取代,目前版本4.5.x,我们现在用的就是4.5版本

HttpClient连接池使用

为什么要用Http连接池:

1、降低延迟:如果不采用连接池,每次连接发起Http请求的时候都会重新建立TCP连接(经历3次握手),用完就会关闭连接(4次挥手),如果采用连接池则减少了这部分时间损耗

2、支持更大的并发:如果不采用连接池,每次连接都会打开一个端口,在大并发的情况下系统的端口资源很快就会被用完,导致无法建立新的连接
  • 默认http协议:
private static final Charset CHAR_SET = Charset.forName("utf-8");
private static PoolingHttpClientConnectionManager cm;

	public void init() {
		cm = new PoolingHttpClientConnectionManager();
		cm.setMaxTotal(50);
		cm.setDefaultConnectionConfig(ConnectionConfig.custom()
				.setCharset(CHAR_SET).build());
		SocketConfig socketConfig = SocketConfig.custom().setSoTimeout(30000)
				.setSoReuseAddress(true).build();
		cm.setDefaultSocketConfig(socketConfig);
		// HttpProtocolParams.setContentCharset(httpParams, "UTF-8");
		// HttpClientParams.setCookiePolicy(httpParams, "ignoreCookies");
		// HttpConnectionParams.setConnectionTimeout(httpParams, 30000);
		// HttpConnectionParams.setSoTimeout(httpParams, 30000);
		httpClient = HttpClientBuilder.create().setConnectionManager(cm)
				.build();
	}

	public CloseableHttpClient getHttpClient() {
		int timeout=2;
		RequestConfig config = RequestConfig.custom()
				.setConnectTimeout(timeout * 1000) //设置连接超时时间,单位毫秒
				//.setConnectionRequestTimeout(timeout * 1000) //设置从connect Manager获取Connection 超时时间,单位毫秒
				.setSocketTimeout(timeout * 1000).build(); //请求获取数据的超时时间,单位毫秒
		CloseableHttpClient _httpClient = HttpClients.custom()
				.setConnectionManager(cm).setDefaultRequestConfig(config)
				.build();
		if(cm!=null&&cm.getTotalStats()!=null) { //打印连接池的状态		
			LOGGER.info("now client pool {}",cm.getTotalStats().toString());
		}
		return _httpClient;
	}

	public String post(String url, Map<String, String> params) {
		HttpPost post = new HttpPost(url);
		String resp = null;
		try {
			if(params != null){
				List<NameValuePair> nvps = new ArrayList<NameValuePair>();
				for (Map.Entry<String, String> param : params.entrySet()) {
					nvps.add(new BasicNameValuePair(param.getKey(), param.getValue()));
				}
				post.setEntity(new UrlEncodedFormEntity(nvps, CHAR_SET));
			}
			
			try {
				HttpResponse response = httpClient.execute(post);
				InputStream input = response.getEntity().getContent();
				resp = IOUtils.toString(input);
			} catch (ClientProtocolException e) {
				LOGGER.error(e.getMessage(), e);
			} catch (IOException e) {
				LOGGER.error(e.getMessage(), e);
			} catch (Exception e) {
				LOGGER.error(e.getMessage(), e);
			}
		} finally {
			if (post != null)
				post.releaseConnection();
		}
		return resp;
	}
  • https协议:
public class HttpConnectionManager {

    PoolingHttpClientConnectionManager cm = null;
    
    public void init() {
        LayeredConnectionSocketFactory sslsf = null;
        try {
            sslsf = new SSLConnectionSocketFactory(SSLContext.getDefault());
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        
        Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory> create()
                .register("https", sslsf)
                .register("http", new PlainConnectionSocketFactory())
                .build();
        cm =new PoolingHttpClientConnectionManager(socketFactoryRegistry);
        cm.setMaxTotal(200);
        cm.setDefaultMaxPerRoute(20);
    }

    public CloseableHttpClient getHttpClient() {       
        CloseableHttpClient httpClient = HttpClients.custom()
                .setConnectionManager(cm)
                .build();          
        
        /*
        //如果不采用连接池就是这种方式获取连接
        CloseableHttpClient httpClient = HttpClients.createDefault();
        */
        return httpClient;
    }
}
  • httpClient使用
catch (Exception e) {
            logger.error("ufile send error e:",e);
            try {
                if (resEntity != null && resEntity.getContent() != null) {
                    resEntity.getContent().close();
                }
            } catch (IllegalStateException | IOException e1) {
                logger.error("ufile send error e1:",e1);
            } finally {
                if (getMethod!=null) {
                    getMethod.releaseConnection();
                }
                /*if (httpClient!=null) { //连接池使用的时候不能关闭连接,否则下次使用会抛异常 java.lang.IllegalStateException: Connection pool shut down
                    try {
                        httpClient.close();
                    } catch (IOException e2) {
                        logger.error("ufile httpclient close error e2:",e2);
                    }
                }*/
            }
        }
  • 连接池使用注意事项:
    1. 连接池中连接都是在发起请求的时候建立,并且都是长连接
    
    2. HttpResponse input.close();作用就是将用完的连接释放,下次请求可以复用,这里特别注意的是,如果不使用in.close();而仅仅使用httpClient.close();结果就是连接会被关闭,并且不能被复用,这样就失去了采用连接池的意义。
    
    3. 连接池释放连接的时候,并不会直接对TCP连接的状态有任何改变,只是维护了两个Set,leased和avaliabled,leased代表被占用的连接集合,avaliabled代表可用的连接的集合,释放连接的时候仅仅是将连接从leased中remove掉了,并把连接放到avaliabled集合中
    

打印的状态:

INFO c.m.p.u.h.HttpClientUtils[72] - now client pool [leased: 0; pending: 0; available: 0; max: 50]

leased :the number of persistent connections tracked by the connection manager currently being used to execute requests.  
  
available :the number idle persistent connections.  
  
pending : the number of connection requests being blocked awaiting a free connection.  
  
max: the maximum number of allowed persistent connections.  

HttpClient 4.5超时设置

4.5版本中,这两个参数的设置都抽象到了RequestConfig中,由相应的Builder构建,具体的例子如下:

CloseableHttpClient httpclient = HttpClients.createDefault();  
HttpGet httpGet = new HttpGet("http://stackoverflow.com/");  
RequestConfig requestConfig = RequestConfig.custom()  
      .setConnectTimeout(5000).setConnectionRequestTimeout(1000)  
      .setSocketTimeout(5000).build();  
httpGet.setConfig(requestConfig);  
CloseableHttpResponse response = httpclient.execute(httpGet);  
System.out.println("得到的结果:" + response.getStatusLine());//得到请求结果  
HttpEntity entity = response.getEntity();//得到请求回来的数据
  • setConnectTimeout:设置连接超时时间,单位毫秒。ConnectTimeoutException
  • setConnectionRequestTimeout:设置从connect Manager获取Connection 超时时间,单位毫秒。这个属性是新加的属性,因为目前版本是可以共享连接池的。ConnectionPoolTimeout
  • setSocketTimeout:请求获取数据的超时时间,单位毫秒。 如果访问一个接口,多少时间内无法返回数据,就直接放弃此次调用。SocketTimeoutException
  • 上面3个时间4.5版本默认是-1,就是不限,如果不设置就会一直等待

java.lang.IllegalStateException: Connection pool shut down

标签:连接超时   reference   prot   eval   rest   一句话   conf   eva   clear   

原文地址:https://www.cnblogs.com/Eillot/p/9042284.html

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