2019独角兽企业重金招聘Python工程师标准>>> 
在后台发送http请求时，每次都要经过三次握手的过程，这是一个比较耗时的操作且稳定性不好，经常连接失败。所以采用httpclient连接池，发起请求时直接从池里面获取连接，不用每次发起请求都经过三次握手，大大的提高的并发的效率
1.maven依赖
<dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId><version>4.5.2</version>
</dependency>
<dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.3</version>
</dependency>
2.http请求工具类
package com.litice.core.util;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.LayeredConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.alibaba.fastjson.JSONObject;
import java.io.IOException;
import java.net.URLDecoder;
import java.security.NoSuchAlgorithmException;
import javax.net.ssl.SSLContext;
public class HttpJsonUtil {private static Logger logger = LoggerFactory.getLogger(HttpJsonUtil.class);// 默认超时时间：10sprivate static final int TIME_OUT = 10 * 1000; private static PoolingHttpClientConnectionManager cm = null;static{LayeredConnectionSocketFactory sslsf = null;try{sslsf = new SSLConnectionSocketFactory(SSLContext.getDefault());}catch(NoSuchAlgorithmException e){logger.error("创建SSL连接失败...");}Registry<ConnectionSocketFactory> sRegistry = RegistryBuilder.<ConnectionSocketFactory>create().register("https", sslsf).register("http", new PlainConnectionSocketFactory()).build();cm = new PoolingHttpClientConnectionManager(sRegistry);// 设置最大的连接数cm.setMaxTotal(200);// 设置每个路由的基础连接数【默认，每个路由基础上的连接不超过2个，总连接数不能超过20】cm.setDefaultMaxPerRoute(20);} private static CloseableHttpClient getHttpClient(){CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(cm).build();return httpClient;}/*** 发送get请求* @param url 路径* @return*/public static JSONObject httpGet(String url) {JSONObject jsonResult = null;CloseableHttpClient httpClient = getHttpClient();// get请求返回结果CloseableHttpResponse response = null;try {// 配置请求超时时间RequestConfig requestConfig = RequestConfig.custom() .setConnectTimeout(TIME_OUT).setConnectionRequestTimeout(TIME_OUT) .setSocketTimeout(TIME_OUT).build();// 发送get请求HttpGet request = new HttpGet(url);request.setConfig(requestConfig);response = httpClient.execute(request);// 请求发送成功，并得到响应 if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {// 读取服务器返回过来的json字符串数据String strResult = EntityUtils.toString(response.getEntity());// 把json字符串转换成json对象jsonResult = JSONObject.parseObject(strResult);url = URLDecoder.decode(url, "UTF-8");} else {logger.error("get请求提交失败:" + url);}} catch (IOException e) {logger.error("get请求提交失败:" + url, e);} finally {if( response != null){try {EntityUtils.consume(response.getEntity());response.close();} catch (IOException e) {logger.error("关闭response失败:", e);}}}return jsonResult;}
}
```
