前言：
项目调用第三方接口时，通常是用socket或者http的通讯方式发送请求：http 为短连接，客户端发送请求都需要服务器端回送响应，请求结束后，主动释放链接。Socket为长连接：通常情况下Socket 连接就是 TCP 连接，因此 Socket 连接一旦建立,通讯双方开始互发数据内容，直到双方断开连接。下面介绍HTTP的方式发送和接收JSON报文。
需求：
用HTTP的方式，向URL为10.10.10.110:8888地址发送json报文，返回的结果也是json报文。
主要代码如下：
1 String resp= null;
2 JSONObject obj = new JSONObject();
3 obj.put("name", "张三");
4 obj.put("age", "18");
5 String query = obj.toString();
6 log.info("发送到URL的报文为：");
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("返回来的报文："+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 }
网上还有一种拼json发送报文的方式，也把代码分享出来：
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("返回来的报文："+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 }
两种方式其实都是一样的。写得不对的地方，往各位撸过的大拿指正~