将C#程序转化成java程序

Question

public String postDataToUrl(String PostData, String PostUrl, String PostEncod, boolean UrlEncode, boolean ToBase64, String contentType)
{
Encoding RequstEncod = Encoding.GetEncoding("UTF-8");

    if (PostEncod != null)
    {
        RequstEncod = Encoding.GetEncoding(PostEncod);
    }
    //URL编码
    if (UrlEncode)
    {
        PostData = HttpUtility.UrlEncode(PostData);
    }

    byte[] data = RequstEncod.GetBytes(PostData);
    //进行64位编码
    if (ToBase64)
    {
        data = RequstEncod.GetBytes(Convert.ToBase64String(data));
    }

    ServicePointManager.ServerCertificateValidationCallback = delegate(object sender, System.Security.Cryptography.X509Certificates.X509Certificate xc,

System.Security.Cryptography.X509Certificates.X509Chain c, System.Net.Security.SslPolicyErrors se)
{
return true;
};

    //创建请求对象
    HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(PostUrl);
    if (httpWebRequest == null)
    {
        return "";
    }
    #region 填充httpWebRequest的基本信息
    httpWebRequest.ContentType = contentType;
    httpWebRequest.Method = "Post";
    #endregion
    httpWebRequest.ContentLength = data.Length;
    try
    {
        Stream RequestStream = httpWebRequest.GetRequestStream();
        RequestStream.Write(data, 0, data.Length);
        RequestStream.Close();
        #region 接收返回数据
        Stream ResponseStream;
        string stringResponse = string.Empty;
        ResponseStream = httpWebRequest.GetResponse().GetResponseStream();
        using (StreamReader sr = new StreamReader(ResponseStream, RequstEncod))
        {
            stringResponse = sr.ReadToEnd();
        }
        ResponseStream.Close();
        return stringResponse;

        #endregion

    }
    catch (Exception ex)
    {
        return ex.Message;
    }
}