java sends an HTTP request (XML format messages)

package io.renren.common.utils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.ConnectException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * 发送HTTP的一种方法
 * GaoLiang
 */
public class HttpSendUtil {

    public static String testPost(String urlStr, String xmlInfo) {
        try {
            URL url = new URL(urlStr);
            URLConnection con = url.openConnection();
            con.setDoOutput(true);
//            con.setRequestProperty("Pragma:", "no-cache");
//            con.setRequestProperty("Cache-Control", "no-cache");
            // 一定要设置报文格式，否则发送失败
            con.setRequestProperty("Content-Type", "text/xml");

            OutputStreamWriter out = null;
            try {
                out = new OutputStreamWriter(con.getOutputStream());
            } catch (ConnectException e) {
//                e.printStackTrace();
                return "Connection refused";
            }
//            System.out.println("urlStr=" + urlStr);
//            System.out.println("xmlInfo=" + xmlInfo);
            out.write(new String(xmlInfo.getBytes("ISO-8859-1")));
            out.flush();
            out.close();
            BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream()));
            StringBuilder stringBuilder = new StringBuilder();
            String line = "";
            for (line = br.readLine(); line != null; line = br.readLine()) {
//                System.out.println(line);
                stringBuilder.append(line);
            }
            return stringBuilder.toString();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

}