Question

这是我的第一个问题，所以请耐心等待。

我有一个Swing应用程序，它通过HttpURLConnection从服务器获取XML格式的数据。现在我正在尝试与服务器创建一个持续的请求 - 响应连接，以检查应用程序是否有任何更新（因为检查必须定期且经常（每隔一秒左右））。

在一些问题的评论中，我读到最好使用Apache HttpClient而不是HttpURLConnection来维护实时连接，但我找不到任何好的例子如何从我当前的代码转到使用HttpClient的代码。具体来说，使用什么而不是HttpURLConnection.setRequestProperty（）和HttpURLConnection.getOutputStream（）？

Document request = new Document(xmlElement);
Document response = new Document();

String server = getServerURL(datasetName);
try {
  URL url = new URL(server);
  try {
    HttpURLConnection connection = (HttpURLConnection)url.openConnection();
    connection.setRequestProperty("Content-Type","application/xml; charset=ISO-8859-1");
    connection.setDoOutput(true);
    connection.setDoInput(true);
    connection.setRequestMethod("POST");
    OutputStream output = connection.getOutputStream();

    XMLOutputter serializer = new XMLOutputter();
    serializer.output(request, output);

    output.flush();
    output.close();

    InputStream input = connection.getInputStream();
    String tempString = ErrOut.printToString(input);

    SAXBuilder parser = new SAXBuilder();
    try {
      response = parser.build(new StringReader(tempString));
    }
    catch (JDOMException ex) { ... }
    input.close();
    connection.disconnect();
  }
  catch (IOException ex) { ... }
}
catch (MalformedURLException ex) { ... }

Answer 1

我认为apache提供了所有示例..如果您使用的是httpclient 4，则可以参考此网址http://hc.apache.org/httpcomponents-client-ga/examples.html

此外，您可能会发现这个有用的.. w.r.t设置响应类型等http://hc.apache.org/httpcomponents-client-ga/tutorial/html/fundamentals.html

Answer 2

感谢Santosh和Raveesh Sharma的回答。我最终使用了StringEntity，这就是我现在所拥有的：

Document request = new Document(xmlElement);
Document response = new Document();

XMLOutputter xmlOutputter = new XMLOutputter();
String xml = xmlOutputter.outputString(request);

HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(getServerURL(datasetName));
post.setHeader("Content-type", "application/xml; charset=ISO-8859-1");

try
{
  StringEntity se = new StringEntity(xml);
  se.setContentType("text/xml");
  post.setEntity(se);
}
catch (UnsupportedEncodingException e) { ... }

try
{
  HttpResponse httpResponse = client.execute(post);

  BufferedReader rd = new BufferedReader(new InputStreamReader(httpResponse.getEntity().getContent()));
  String line = "";
  String tempString = "";
  while ((line = rd.readLine()) != null)
  {
    tempString += line;
  }

  SAXBuilder parser = new SAXBuilder();
  try
  {
    response = parser.build(new StringReader(tempString));
  }
  catch (JDOMException ex) { ... }
}
catch (IOException ex) { ... }

Answer 3

这是您需要的代码段（这取代了您在try块中拥有的大部分内容），

try {
String postURL= server;
HttpClient client = new HttpClient();
PostMethod postMethod = new PostMethod(postURL);;
client.executeMethod(postMethod);
InputStream input = postMethod.getResponseBodyAsStream();   
//--your subsequent code here

编辑：以下是posting XML to a server使用Http-Client的示例。

如何从HttpURLConnection切换到HttpClient

3 个答案: