基於\httpcomponents-client-4.5.5需要引入相關jar包如下：

必須導入commons-logging-1.2.jar，否則會提示

json api接口地址：

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

本例用了百度上的那個接口

測試代碼：

 1 import org.apache.http.HttpStatus;
 2 import org.apache.http.client.config.RequestConfig;
 3 import org.apache.http.client.methods.CloseableHttpResponse;
 
 4 import org.apache.http.client.methods.HttpGet;
 5 import org.apache.http.client.methods.HttpPost;
 6 import org.apache.http.entity.StringEntity;
 7 import org.apache.http.impl.client.CloseableHttpClient;
 8 import org.apache.http.impl.client.HttpClients;
 9 import org.apache.http.util.EntityUtils;
 
10 
11 
12 public class HttpServletUtil {
13     public static void main(String args[]) throws Exception{
14         
15         HttpServletUtil httpServletUtil = new HttpServletUtil();
16         String url = "http://baike.baidu.com/api/openapi/BaikeLemmaCardApi?";
17         String params = "scope=103&format=json&appid=379020&bk_key=關鍵字&bk_length=600";
 
18         String s = HttpServletUtil.doPost(params, url);
19         System.out.println(s);
20     }
21 
22   
23     public static String doPost(String params, String url) throws Exception {
24         String result = null;
25         CloseableHttpClient httpclient = HttpClients.createDefault();
26         RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(5000).setConnectTimeout(5000).build();
27         HttpPost httpPost = new HttpPost(url);
28         StringEntity entity = new StringEntity(params.toString(), "utf-8");
29         httpPost.setEntity(entity);
30         //設置請求和傳輸超時時間
31         httpPost.setConfig(requestConfig);
32         CloseableHttpResponse httpResp = httpclient.execute(httpPost);
33         try {
34             int statusCode = httpResp.getStatusLine().getStatusCode();
35             // 判斷是夠請求成功
36             if (statusCode == HttpStatus.SC_OK) {
37                 System.out.println("狀態碼:" + statusCode);
38                 System.out.println("請求成功!");
39                 // 獲取返回的數據
40                 result = EntityUtils.toString(httpResp.getEntity(), "UTF-8");
41             } else {
42                 System.out.println("狀態碼:"
43                         + httpResp.getStatusLine().getStatusCode());
44                 System.out.println("HttpPost方式請求失敗!");
45             }
46         } finally {
47             httpResp.close();
48             httpclient.close();
49         }
50         return result;
51     }
52 
53         /*public static String doGet(String url) throws Exception{
54         String result = null;
55         httpclient = HttpClients.createDefault();
56         HttpGet httpGet = new HttpGet(url);
57         //設置請求和傳輸超時時間
58         //httpGet.setConfig(requestConfig);
59         CloseableHttpResponse httpResp = httpclient.execute(httpGet);
60         try {
61             int statusCode = httpResp.getStatusLine().getStatusCode();
62             // 判斷是夠請求成功
63             if (statusCode == HttpStatus.SC_OK) {
64                 System.out.println("狀態碼:" + statusCode);
65                 System.out.println("請求成功!");
66                 // 獲取返回的數據
67                 result = EntityUtils.toString(httpResp.getEntity(), "UTF-8");
68             } else {
69                 System.out.println("狀態碼:"
70                         + httpResp.getStatusLine().getStatusCode());
71                 System.out.println("HttpGet方式請求失敗!");
72             }
73         } finally {
74             httpResp.close();
75             httpclient.close();
76         }
77         return result;
78      }*/
79 }

請求成功後如下

httpclient 請求 json 數據