java 发起http请求

public static JSONObject sendPost(String pathUrl, String requestString, String method) {
		JSONObject json = new JSONObject();
		// 建立连接
		try {
			URL url = new URL(pathUrl);
			HttpURLConnection httpUrlConnection = (HttpURLConnection) url.openConnection();
			// 设置连接属性
			httpUrlConnection.setDoOutput(true);// 使用 URL 连接进行输出
			httpUrlConnection.setDoInput(true);// 使用 URL 连接进行输入
			httpUrlConnection.setUseCaches(false);// 忽略缓存
			httpUrlConnection.setRequestMethod(method);// 设置URL请求方法
			httpUrlConnection.setRequestProperty("CHARSET", "UTF-8");
			// 设置请求属性
			// 获得数据字节数据，请求数据流的编码，必须和下面服务器端处理请求流的编码一致
			byte[] requestStringBytes = requestString.getBytes("UTF-8");
			httpUrlConnection.setRequestProperty("Content-length", "" + requestStringBytes.length);
			httpUrlConnection.setRequestProperty("Content-Type", "application/json");
			httpUrlConnection.setRequestProperty("Connection", "Keep-Alive");// 维持长连接
			httpUrlConnection.setRequestProperty("Charset", "UTF-8");

			// 建立输出流，并写入数据
			OutputStream outputStream = httpUrlConnection.getOutputStream();
			outputStream.write(requestStringBytes);
			outputStream.close();
			// 获得响应状态
			int responseCode = httpUrlConnection.getResponseCode();
			String readLine = null;
			if (HttpURLConnection.HTTP_OK == responseCode) {// 连接成功
				// 当正确响应时处理数据
				StringBuffer sb = new StringBuffer();

				BufferedReader responseReader;
				// 处理响应流，必须与服务器响应流输出的编码一致
				responseReader = new BufferedReader(new InputStreamReader(httpUrlConnection.getInputStream(), "UTF-8"));
				while ((readLine = responseReader.readLine()) != null) {
					sb.append(readLine).append("\n");
				}
				responseReader.close();
				String result = sb.toString();
				// 处理返回的参数
				if (!"".equals(result)) {
					json = JSONObject.parseObject(result);
				}
			}
			json.put("HTTP_CODE", responseCode);
		} catch (Exception e) {

		}
		return json;
	}