使用Apache HttpClient 4.x发送Json数据

Apache HttpClient是Apache提供的一个开源组件，使用HttpClient可以很方便地进行Http请求的调用。自4.1版本开始，HttpClient的API发生了较大的改变，很多方法的调用方式已经和3.x版本不同。本文使用的是当前最新的4.5.3版本。

首先在pom文件中引入httpcomponents依赖包：

 <dependency>

     <groupId>org.apache.httpcomponents</groupId>

     <artifactId>httpclient</artifactId>

     <version>4.5.3</version>

 </dependency>

本文展示的是POST请求。

 import java.io.IOException;

 import org.apache.commons.lang3.ObjectUtils;

 import org.apache.commons.lang3.StringUtils;

 import org.apache.http.Consts;

 import org.apache.http.HttpStatus;

 import org.apache.http.ParseException;

 import org.apache.http.client.config.RequestConfig;

 import org.apache.http.client.methods.CloseableHttpResponse;

 import org.apache.http.client.methods.HttpPost;

 import org.apache.http.entity.ContentType;

 import org.apache.http.entity.StringEntity;

 import org.apache.http.impl.client.CloseableHttpClient;

 import org.apache.http.impl.client.HttpClients;

 import org.apache.http.util.EntityUtils;

 /**

  * @author

  *

  * @date 2017年5月18日 上午9:17:30

  *

  * @Description

  */

 public class HttpPostUtils {

     /**

      *

      * @param uri

      *            the request address

      * @param json

      *            the request data that must be a JSON string

      * @param connectTimeout

      *            the timeout in milliseconds until a connection is established

      * @param connectionRequestTimeout

      *            the timeout in milliseconds used when requesting a connection

      *            from the connection manager

      * @param socketTimeout

      *            the socket timeout in milliseconds, which is the timeout for

      *            waiting for data or, put differently, a maximum period

      *            inactivity between two consecutive data packets

      * @return null when method parameter is null, "", " "

      * @throws IOException

      *             if HTTP connection can not opened or closed successfully

      * @throws ParseException

      *             if response data can not be parsed successfully

      */

     public String postJson(String uri, String json, int connectTimeout, int connectionRequestTimeout, int socketTimeout)

             throws IOException, ParseException {

         if (StringUtils.isAnyBlank(uri, json)) {

             return null;

         }

         CloseableHttpClient client = HttpClients.createDefault();

         HttpPost post = new HttpPost(uri);

         // Create request data

         StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);

         // Set request body

         post.setEntity(entity);

         RequestConfig config = RequestConfig.custom().setConnectTimeout(connectTimeout)

                 .setConnectionRequestTimeout(connectionRequestTimeout).setSocketTimeout(socketTimeout).build();

         post.setConfig(config);

         // Response content

         String responseContent = null;

         CloseableHttpResponse response = null;

         try {

             response = client.execute(post);

             if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                 responseContent = EntityUtils.toString(response.getEntity(), Consts.UTF_8.name());

             }

         } finally {

             if (ObjectUtils.anyNotNull(response)) {

                 response.close();

             }

             if (ObjectUtils.anyNotNull(client)) {

                 client.close();

             }

         }

         return responseContent;

     }

 }