1.依赖

   <!--httpClient -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.9</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.5.9</version>
        </dependency>

2.代码

public class HttpClientUtil {

    /**
     * 默认参数设置
     * setConnectTimeout：设置连接超时时间，单位毫秒。
     * setConnectionRequestTimeout：设置从connect Manager获取Connection 超时时间，单位毫秒。
     * setSocketTimeout：请求获取数据的超时时间，单位毫秒。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。 暂时定义15分钟
     */
    private RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(600000).setConnectTimeout(600000).setConnectionRequestTimeout(600000).build();

    /**
     * 静态内部类---作用：单例产生类的实例
     *
     * @author Administrator
     */
    private static class LazyHolder {
        private static final HttpClientUtil INSTANCE = new HttpClientUtil();

    }

    private HttpClientUtil() {
    }

    public static HttpClientUtil getInstance() {
        return LazyHolder.INSTANCE;
    }

    /**
     * 发送 post请求
     *
     * @param httpUrl 地址
     */
    public String sendHttpPost(String httpUrl) {
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
        return sendHttpPost(httpPost);
    }

    /**
     * 发送 post请求
     *
     * @param httpUrl 地址
     * @param params  参数(格式:key1=value1&key2=value2)
     */
    public String sendHttpPost(String httpUrl, String params) {
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
        try {
            //设置参数
            StringEntity stringEntity = new StringEntity(params, "UTF-8");
            stringEntity.setContentType("application/x-www-form-urlencoded");
            httpPost.setEntity(stringEntity);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sendHttpPost(httpPost);
    }

    public byte[] sendHttpPostByte(String httpUrl, String params) {
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
        try {
            //设置参数
            StringEntity stringEntity = new StringEntity(params, "UTF-8");
            stringEntity.setContentType("application/x-www-form-urlencoded");
            httpPost.setEntity(stringEntity);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sendHttpPostByte(httpPost);
    }

    /**
     * 发送 post请求
     *
     * @param httpUrl 地址
     * @param maps    参数
     */
    public String sendHttpPost(String httpUrl, Map<String, String> maps) {
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
        // 创建参数队列
        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
        for (String key : maps.keySet()) {
            nameValuePairs.add(new BasicNameValuePair(key, maps.get(key)));
        }
        try {
            httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs, "UTF-8"));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sendHttpPost(httpPost);
    }

    /**
     * 发送Post请求
     *
     * @param httpPost
     * @return
     */
    private String sendHttpPost(HttpPost httpPost) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        HttpEntity entity = null;
        String responseContent = null;
        try {
            // 创建默认的httpClient实例
            httpClient = HttpClients.createDefault();
            httpPost.setConfig(requestConfig);
            // 执行请求
            long execStart = System.currentTimeMillis();
            response = httpClient.execute(httpPost);
            long execEnd = System.currentTimeMillis();
            System.out.println("=================执行post请求耗时：" + (execEnd - execStart) + "ms");
            long getStart = System.currentTimeMillis();
            entity = response.getEntity();
            responseContent = EntityUtils.toString(entity, "UTF-8");
            long getEnd = System.currentTimeMillis();
            System.out.println("=================获取响应结果耗时：" + (getEnd - getStart) + "ms");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭连接,释放资源
                if (response != null) {
                    response.close();
                }
                if (httpClient != null) {
                    httpClient.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return responseContent;
    }

    private byte[] sendHttpPostByte(HttpPost httpPost) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        HttpEntity entity = null;
        byte[] responseContent = null;
        try {
            // 创建默认的httpClient实例
            httpClient = HttpClients.createDefault();
            httpPost.setConfig(requestConfig);
            // 执行请求
            long execStart = System.currentTimeMillis();
            response = httpClient.execute(httpPost);
            long execEnd = System.currentTimeMillis();
            System.out.println("=================执行post请求耗时：" + (execEnd - execStart) + "ms");
            long getStart = System.currentTimeMillis();
            entity = response.getEntity();
            responseContent = EntityUtils.toByteArray(entity);
            long getEnd = System.currentTimeMillis();
            System.out.println("=================获取响应结果耗时：" + (getEnd - getStart) + "ms");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭连接,释放资源
                if (response != null) {
                    response.close();
                }
                if (httpClient != null) {
                    httpClient.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return responseContent;
    }


    /**
     * 发送 get请求
     *
     * @param httpUrl
     */
    public String sendHttpGet(String httpUrl) {
        HttpGet httpGet = new HttpGet(httpUrl);// 创建get请求
        return sendHttpGet(httpGet);
    }

    /**
     * 发送 get请求Https
     *
     * @param httpUrl
     */
    public String sendHttpsGet(String httpUrl) {
        HttpGet httpGet = new HttpGet(httpUrl);// 创建get请求
        return sendHttpsGet(httpGet);
    }

    /**
     * 发送Get请求
     * @param httpGet
     * @return
     */
    private String sendHttpGet(HttpGet httpGet) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        HttpEntity entity = null;
        String responseContent = null;
        try {
            // 创建默认的httpClient实例.
            httpClient = HttpClients.createDefault();

            httpGet.setConfig(requestConfig);
            // 执行请求
            response = httpClient.execute(httpGet);
            entity = response.getEntity();
            responseContent = EntityUtils.toString(entity, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭连接,释放资源
                if (response != null) {
                    response.close();
                }
                if (httpClient != null) {
                    httpClient.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return responseContent;
    }

    /**
     * 发送Get请求Https
     * @param httpGet
     * @return
     */
    private String sendHttpsGet(HttpGet httpGet) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        HttpEntity entity = null;
        String responseContent = null;
        try {
            // 创建默认的httpClient实例.
            PublicSuffixMatcher publicSuffixMatcher = PublicSuffixMatcherLoader.load(new URL(httpGet.getURI().toString()));
            DefaultHostnameVerifier hostnameVerifier = new DefaultHostnameVerifier(publicSuffixMatcher);
            httpClient = HttpClients.custom().setSSLHostnameVerifier(hostnameVerifier).build();
            httpGet.setConfig(requestConfig);
            // 执行请求
            response = httpClient.execute(httpGet);
            entity = response.getEntity();
            responseContent = EntityUtils.toString(entity, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭连接,释放资源
                if (response != null) {
                    response.close();
                }
                if (httpClient != null) {
                    httpClient.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return responseContent;
    }


}

3.使用

HttpClientUtil.getInstance().sendHttpPostByte(requestUrl, jsonObject.toJSONString());