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127.0.0.1:8888地址发送json报文,返回的结果也是json报文。

主要代码如下:

String resp= null;
JSONObject obj = new JSONObject();
obj.put("name", "张三");   
obj.put("age", "18");   
String query = obj.toString();
log.info("发送到URL的报文为:");
log.info(query);
try {
	URL url = new URL("http://127.0.0.1:8888"); //url地址
	HttpURLConnection connection = (HttpURLConnection) 			url.openConnection();
	connection.setDoInput(true);
	connection.setDoOutput(true);
	connection.setRequestMethod("POST");
	connection.setUseCaches(false);
	connection.setInstanceFollowRedirects(true);
	connection.setRequestProperty("Content-Type","application/json");
	connection.connect();
	try (OutputStream os = connection.getOutputStream()) {
		os.write(query.getBytes("UTF-8"));
	}
	try (BufferedReader reader = new BufferedReader(
		new InputStreamReader(connection.getInputStream()))) {
		String lines;
		StringBuffer sbf = new StringBuffer();
		while ((lines = reader.readLine()) != null) {
			lines = new String(lines.getBytes(), "utf-8");
			sbf.append(lines);
		}
		log.info("返回来的报文:"+sbf.toString());
		resp = sbf.toString();    
	}
	connection.disconnect();
} catch (Exception e) {
	e.printStackTrace();
}finally{
	JSONObject json = (JSONObject)JSON.parse(resp);
}

网上还有一种拼json发送报文的方式,也把代码分享出来:

String resp = null;
String name = request.getParameter("userName");
String age = request.getParameter("userAge");
String query = "{\"name\":\""+name+"\",\"age\":\""+age+"\"}";

try {
	URL url = new URL("http://10.10.10.110:8888"); //url地址
	HttpURLConnection connection = (HttpURLConnection) url.openConnection();
	connection.setDoInput(true);
	connection.setDoOutput(true);
	connection.setRequestMethod("POST");
	connection.setUseCaches(false);
	connection.setInstanceFollowRedirects(true);
	connection.setRequestProperty("Content-Type","application/json");
	connection.connect();
	try (OutputStream os = connection.getOutputStream()) {
		os.write(query.getBytes("UTF-8"));
	}

	try (BufferedReader reader = new BufferedReader(
		new InputStreamReader(connection.getInputStream()))) {
		String lines;
		StringBuffer sbf = new StringBuffer();
		while ((lines = reader.readLine()) != null) {
		lines = new String(lines.getBytes(), "utf-8");
		sbf.append(lines);
	}
	log.info("返回来的报文:"+sbf.toString());
	resp = sbf.toString();    
}
connection.disconnect();
} catch (Exception e) {
	e.printStackTrace();
}finally{
	JSONObject json = (JSONObject)JSON.parse(resp);
}