[网络协议]HttpClient发送get请求（避免校验SSL证书）

项目需要通过CFC远程访问，最开始项目在本地，没有发现问题，部署到公网测试环境后发现报异常: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

百度发现是公网环境域名证书的问题

于是把远程访问的方式更改为CloseableHttpClient

注意不要在发送get请求后关闭httpclient，上来手贱在finally里面都给关闭了，结果只有首次访问能通，冥思苦想一晚上才弄明白

package com.baidu.dueros.bot;

import org.apache.commons.lang.StringUtils;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.util.EntityUtils;
import javax.net.ssl.SSLContext;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

public class HttpUtil {

    private static CloseableHttpClient httpClient;

    /**
     * 信任SSL证书
     */
    static {
        try {
            SSLContext sslContext = SSLContextBuilder.create().useProtocol(SSLConnectionSocketFactory.SSL).loadTrustMaterial((x, y) -> true).build();
            RequestConfig config = RequestConfig.custom().setConnectTimeout(5000).setSocketTimeout(5000).build();
            httpClient = HttpClientBuilder.create().setDefaultRequestConfig(config).setSSLContext(sslContext).setSSLHostnameVerifier((x, y) -> true).build();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * get请求
     * @param url 请求地址加参数
     * @return 响应
     */
    public static String get(String url)
    {
        String result = null;
        HttpGet get = new HttpGet(url);
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(get);
            if(response != null && response.getStatusLine().getStatusCode() == 200)
            {
                HttpEntity entity = response.getEntity();
                if (entity != null) {
                    result = EntityUtils.toString(entity, "utf-8");
                }
                EntityUtils.consume(entity);
                response.close();
            }
            return result;
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                if(response != null)
                {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

   
}