httpclient 请求 json 数据

基于\httpcomponents-client-4.5.5需要引入相关jar包如下：

必须导入commons-logging-1.2.jar，否则会提示

json api接口地址：

https://www.bejson.com/knownjson/webInterface/

本例用了百度上的那个接口

测试代码：

 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.client.methods.HttpPost;
 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;

 import com.sun.java.swing.plaf.windows.resources.windows;

 public class HttpServletUtil {

     String result = null;
     CloseableHttpClient httpclient = HttpClients.createDefault();
     RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(5000).setConnectTimeout(5000).build();

     public String doPost(String params, String url) throws Exception {

         HttpPost httpPost = new HttpPost(url);
         StringEntity entity = new StringEntity(params.toString(), "utf-8");
         httpPost.setEntity(entity);
         //设置请求和传输超时时间
         httpPost.setConfig(requestConfig);
         CloseableHttpResponse httpResp = httpclient.execute(httpPost);
         try {
             int statusCode = httpResp.getStatusLine().getStatusCode();
             // 判断是够请求成功
             if (statusCode == HttpStatus.SC_OK) {
                 System.out.println("状态码:" + statusCode);
                 System.out.println("请求成功!");
                 // 获取返回的数据
                 result = EntityUtils.toString(httpResp.getEntity(), "UTF-8");
             } else {
                 System.out.println("状态码:"
                         + httpResp.getStatusLine().getStatusCode());
                 System.out.println("HttpPost方式请求失败!");
             }
         } finally {
             httpResp.close();
             httpclient.close();
         }
         return result;
     }

     public String doGet(String url) throws Exception{
         String result = null;
         CloseableHttpClient httpclient = HttpClients.createDefault();
         httpclient = HttpClients.createDefault();
         HttpGet httpGet = new HttpGet(url);
         //设置请求和传输超时时间
         httpGet.setConfig(requestConfig);
         CloseableHttpResponse httpResp = httpclient.execute(httpGet);
         try {
             int statusCode = httpResp.getStatusLine().getStatusCode();
             // 判断是够请求成功
             if (statusCode == HttpStatus.SC_OK) {
                 System.out.println("状态码:" + statusCode);
                 System.out.println("请求成功!");
                 // 获取返回的数据
                 result = EntityUtils.toString(httpResp.getEntity(), "UTF-8");
             } else {
                 System.out.println("状态码:"
                         + httpResp.getStatusLine().getStatusCode());
                 System.out.println("HttpGet方式请求失败!");
             }
         } finally {
             httpResp.close();
             httpclient.close();
         }
         return result;
      }

     public static void main(String args[]) throws Exception{

         //String url = "http://baike.baidu.com/api/openapi/BaikeLemmaCardApi";
         //String params = "scope=103&format=json&appid=379020&bk_key=关键字&bk_length=600";
         //String s = HttpServletUtil.doPost(params, url);

         String url = "http://baike.baidu.com/api/openapi/BaikeLemmaCardApi?scope=103&format=json&appid=379020&bk_key=关键字&bk_length=600";
         String s = new HttpServletUtil().doGet(url);
         System.out.println(s);
     }

 }

请求成功后如下