Native http interface transmission

package com.util;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class Http {
	
	/**
     * Basic class post method
     * @param requestUrl request address
     * @param requestXml push data string
     * @return String return data
     */
	public static String sendPost02(String requestUrl, String requestXml) {
		StringBuilder ret = new StringBuilder();
		HttpURLConnection httpCon;
		try {
			httpCon = (HttpURLConnection) (new URL(requestUrl)).openConnection();
			httpCon.setConnectTimeout(1000 * 30);//Set the connection host timeout (unit: milliseconds)
			httpCon.setReadTimeout(1000 * 30);//Set the timeout for reading data from the host (unit: milliseconds)
			httpCon.setDoOutput(true);//Set whether to output to httpUrlConnection, because this is a post request, the parameters should be placed in the http body, so it needs to be set to true, by default it is false;   
			httpCon.setDoInput(true);// Set whether to read in from httpUrlConnection, by default it is true;
			httpCon.setRequestMethod("POST");// Set the request method to "POST", the default is GET
			httpCon.setUseCaches(false);// Post requests cannot use caches
			httpCon.setInstanceFollowRedirects(true);//Set whether this connection automatically handles redirection. If set to true, the system will automatically process the redirection; if set to false, you need to analyze the new url from the http reply and reconnect by yourself.
			//setRequestProperty is mainly to set properties in the HttpURLConnection request header such as Cookie, User-Agent (browser type), etc.
			httpCon.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");//application/x-www-form-urlencoded: Form data is encoded as name/value pairs. This is the standard encoding format. multipart/form-data: Form data is encoded as a message, and each control on the page corresponds to a part of the message. text/plain: The form data is encoded in plain text, without any controls or formatting characters.
			httpCon.connect();

			DataOutputStream postOut = new DataOutputStream(httpCon.getOutputStream());
			String postContent =   requestXml;
			postOut.write(postContent.getBytes("utf-8"));
			postOut.flush();
			postOut.close();

			if (httpCon.getResponseCode() == HttpURLConnection.HTTP_OK) {
				String readLine = null;
				BufferedReader responseReader = new BufferedReader(new InputStreamReader(httpCon.getInputStream(), "UTF-8"));
				while ((readLine = responseReader.readLine()) != null) {
					ret.append(readLine);
				}
				responseReader.close();
			}
		}
		catch (IOException e) {
			e.printStackTrace ();
		}

		return ret.toString();
	}

}