Java 用HTTP的方式發送JSON報文請求

前言：　

　　項目調用第三方接口時，通常是用socket或者http的通訊方式發送請求：http 為短連接，客戶端發送請求都需要服務器端回送響應，請求結束后，主動釋放鏈接。Socket為長連接：通常情況下Socket 連接就是 TCP 連接，因此 Socket 連接一旦建立,通訊雙方開始互發數據內容，直到雙方斷開連接。下面介紹HTTP的方式發送和接收JSON報文。

需求：

　　用HTTP的方式，向URL為10.10.10.110:8888地址發送json報文，返回的結果也是json報文。

主要代碼如下：

 1             String resp= null;
 2             JSONObject obj = new JSONObject();
 3             obj.put("name", "張三");   
 4             obj.put("age", "18");   
 5             String query = obj.toString();
 6             log.info("發送到URL的報文為：");
 7             log.info(query);
 8             try {
 9                 URL url = new URL("http://10.10.10.110:8888"); //url地址
10 
11                 HttpURLConnection connection = (HttpURLConnection) url.openConnection();
12                 connection.setDoInput(true);
13                 connection.setDoOutput(true);
14                 connection.setRequestMethod("POST");
15                 connection.setUseCaches(false);
16                 connection.setInstanceFollowRedirects(true);
17                 connection.setRequestProperty("Content-Type","application/json");
18                 connection.connect();
19 
20                 try (OutputStream os = connection.getOutputStream()) {
21                     os.write(query.getBytes("UTF-8"));
22                 }
23 
24                 try (BufferedReader reader = new BufferedReader(
25                         new InputStreamReader(connection.getInputStream()))) {
26                     String lines;
27                     StringBuffer sbf = new StringBuffer();
28                     while ((lines = reader.readLine()) != null) {
29                         lines = new String(lines.getBytes(), "utf-8");
30                         sbf.append(lines);
31                     }
32                     log.info("返回來的報文："+sbf.toString());
33                     resp = sbf.toString();    
34                    
35                 }
36                 connection.disconnect();
37 
38             } catch (Exception e) {
39                 e.printStackTrace();
40             }finally{
41                 JSONObject json = (JSONObject)JSON.parse(resp);
42             }

網上還有一種拼json發送報文的方式，也把代碼分享出來：

 1 String resp = null;
 2 String name = request.getParameter("userName");
 3 String age = request.getParameter("userAge");
 4 String query = "{\"name\":\""+name+"\",\"age\":\""+age+"\"}";
 5 
 6 try {
 7                 URL url = new URL("http://10.10.10.110:8888"); //url地址
 8 
 9                 HttpURLConnection connection = (HttpURLConnection) url.openConnection();
10                 connection.setDoInput(true);
11                 connection.setDoOutput(true);
12                 connection.setRequestMethod("POST");
13                 connection.setUseCaches(false);
14                 connection.setInstanceFollowRedirects(true);
15                 connection.setRequestProperty("Content-Type","application/json");
16                 connection.connect();
17 
18                 try (OutputStream os = connection.getOutputStream()) {
19                     os.write(query.getBytes("UTF-8"));
20                 }
21 
22                 try (BufferedReader reader = new BufferedReader(
23                         new InputStreamReader(connection.getInputStream()))) {
24                     String lines;
25                     StringBuffer sbf = new StringBuffer();
26                     while ((lines = reader.readLine()) != null) {
27                         lines = new String(lines.getBytes(), "utf-8");
28                         sbf.append(lines);
29                     }
30                     log.info("返回來的報文："+sbf.toString());
31                     resp = sbf.toString();    
32                    
33                 }
34                 connection.disconnect();
35 
36             } catch (Exception e) {
37                 e.printStackTrace();
38             }finally{
39                 JSONObject json = (JSONObject)JSON.parse(resp);
40             }

兩種方式其實都是一樣的。寫得不對的地方，往各位擼過的大拿指正~