httpClient 连接池

public class HttpConnectionPoolUtil {

    private static final int CONNECT_TIMEOUT = 10000;// 设置连接建立的超时时间为10s
    private static final int SOCKET_TIMEOUT = 20000;
    private static final int MAX_CONN = 200; // 最大连接数
    private static final int Max_PRE_ROUTE = 200;
    private static final int MAX_ROUTE = 200;
    private static CloseableHttpClient httpClient; // 发送请求的客户端单例
    private static PoolingHttpClientConnectionManager manager; //连接池管理类
    private static ScheduledExecutorService monitorExecutor;

    private final static Object syncLock = new Object(); // 相当于线程锁,用于线程安全

    /**
     * 对http请求进行基本设置
     *
     * @param httpRequestBase http请求
     */
    private static void setRequestConfig(HttpRequestBase httpRequestBase) {
        RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(CONNECT_TIMEOUT)
                .setConnectTimeout(CONNECT_TIMEOUT)
                .setSocketTimeout(SOCKET_TIMEOUT).build();

        httpRequestBase.setConfig(requestConfig);
    }

    public static CloseableHttpClient getHttpClient(String url) {
        String hostName = url.split("/")[2];
        System.out.println(hostName);
        int port = 80;
        if (hostName.contains(":")) {
            String[] args = hostName.split(":");
            hostName = args[0];
            port = Integer.parseInt(args[1]);
        }

        if (httpClient == null) {
            //多线程下多个线程同时调用getHttpClient容易导致重复创建httpClient对象的问题,所以加上了同步锁
            synchronized (syncLock) {
                if (httpClient == null) {
                    httpClient = createHttpClient(hostName, port);
                    //开启监控线程,对异常和空闲线程进行关闭
                    monitorExecutor = Executors.newScheduledThreadPool(1);
                    monitorExecutor.scheduleAtFixedRate(new TimerTask() {
                        @Override
                        public void run() {
                            //关闭异常连接
                            manager.closeExpiredConnections();
                            //关闭5s空闲的连接
                            manager.closeIdleConnections(10, TimeUnit.SECONDS);
                            System.out.println("close expired and idle for over 5s connection");
                        }
                    }, 10, 10, TimeUnit.SECONDS);
                }
            }
        }
        return httpClient;
    }

    /**
     * 根据host和port构建httpclient实例
     *
     * @param host 要访问的域名
     * @param port 要访问的端口
     * @return
     */
    public static CloseableHttpClient createHttpClient(String host, int port) {
        ConnectionSocketFactory plainSocketFactory = PlainConnectionSocketFactory.getSocketFactory();
        LayeredConnectionSocketFactory sslSocketFactory = SSLConnectionSocketFactory.getSocketFactory();
        Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory>create().register("http", plainSocketFactory)
                .register("https", sslSocketFactory).build();

        manager = new PoolingHttpClientConnectionManager(registry);
        //设置连接参数
        manager.setMaxTotal(MAX_CONN); // 最大连接数
        manager.setDefaultMaxPerRoute(Max_PRE_ROUTE); // 路由最大连接数

        HttpHost httpHost = new HttpHost(host, port);
        manager.setMaxPerRoute(new HttpRoute(httpHost), MAX_ROUTE);

        //请求失败时,进行请求重试
        HttpRequestRetryHandler handler = new HttpRequestRetryHandler() {
            @Override
            public boolean retryRequest(IOException e, int i, HttpContext httpContext) {
                if (i > 3) {
                    //重试超过3次,放弃请求
                    System.out.println("retry has more than 3 time, give up request");
                    return false;
                }
                if (e instanceof NoHttpResponseException) {
                    //服务器没有响应,可能是服务器断开了连接,应该重试
                    System.out.println("receive no response from server, retry");
                    return true;
                }
                if (e instanceof SSLHandshakeException) {
                    // SSL握手异常
                    System.out.println("SSL hand shake exception");
                    return false;
                }
                if (e instanceof InterruptedIOException) {
                    //超时
                    System.out.println("InterruptedIOException");
                    return false;
                }
                if (e instanceof UnknownHostException) {
                    // 服务器不可达
                    System.out.println("server host unknown");
                    return false;
                }
                if (e instanceof ConnectTimeoutException) {
                    // 连接超时
                    System.out.println("Connection Time out");
                    return false;
                }
                if (e instanceof SSLException) {
                    System.out.println("SSLException");
                    return false;
                }

                HttpClientContext context = HttpClientContext.adapt(httpContext);
                HttpRequest request = context.getRequest();
                if (!(request instanceof HttpEntityEnclosingRequest)) {
                    //如果请求不是关闭连接的请求
                    return true;
                }
                return false;
            }
        };

        CloseableHttpClient client = HttpClients.custom().setConnectionManager(manager).setRetryHandler(handler).build();
        return client;
    }

    /**
     * 设置post请求的参数
     *
     * @param httpPost
     * @param params
     */
    private static void setPostParams(HttpPost httpPost, Map<String, String> params) {
        List<NameValuePair> nvps = new ArrayList<NameValuePair>();
        Set<String> keys = params.keySet();
        for (String key : keys) {
            nvps.add(new BasicNameValuePair(key, params.get(key)));
        }
        try {
            httpPost.setEntity(new UrlEncodedFormEntity(nvps, "utf-8"));
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }

    public static String post(String url, Map<String, String> params) {
        HttpPost httpPost = new HttpPost(url);
        setRequestConfig(httpPost);
        setPostParams(httpPost, params);
        CloseableHttpResponse response = null;
        try {
            response = getHttpClient(url).execute(httpPost, HttpClientContext.create());
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                return EntityUtils.toString(entity);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (response != null) response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return "";
    }

    public static String get(String url) {
        HttpGet httpget = new HttpGet(url);
        setRequestConfig(httpget);
        CloseableHttpResponse response = null;
        try {
            response = getHttpClient(url).execute(httpget, HttpClientContext.create());
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                return EntityUtils.toString(entity);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (response != null) response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return "";
    }

    /**
     * 关闭连接池
     */
    public static void closeConnectionPool() {
        try {
            httpClient.close();
            manager.close();
            monitorExecutor.shutdown();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


}