如何管理与服务器的请求-响应对话循环

Question

我正在编写一个简单的客户端-服务器系统，问题是：如何构建我的客户端代码以使 POST 请求-响应循环工作？

目前它看起来像这样（而且现在不是循环）：

1. op​​en HttpURLConnection
2. set properties
3. setDoOutput(true)
4. writing to output flow
5. closeoutputstream
6. new DataInputStreamreading
7. response
8. exiting method

我不确定我有哪些对象为下一次迭代保存以及我应该关闭哪些迭代。

Answer 1

您需要保存连接对象，并且应该使用 setDoInput(true) 来读取数据，但如果您只想读取 responseCode 和 responseMessage > 你不需要InputStream。检查下面的代码。

HttpURLConnection connection =(HttpURLConnection)new URL("url").openConnection();
connection.setDoOutput(true);
connection.setRequestProperty("Content-type", "text/xml"); // depend on you
connection.setRequestProperty("Accept", "text/xml, application/xml"); // depend on you
connection.setRequestMethod("POST");
OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());
writer.write(yaml);
writer.close();
int statusCode = connection.getResponseCode();
String message = connection.getResponseMessage();

对于InputStreamReader

connection.setDoInput(true);
InputStreamReader reader =  new InputStreamReader(connection.getInputStream());
char[] cbuf = new char[100];
reader.read(cbuf); 
// there are 3 read method you can choose as per your convenience 
//and put a check for end of line in while loop for reading whole content. 
reader.close();

Answer 2

在管理了我自己关于这个主题的“研究”之后（感谢谷歌和诺基亚开发者论坛），我得出了我的代码的最终视图。这是一个文件上传循环：

path = Paths.get(requestString);
in = Files.newInputStream(path);

int i = 0;
while ((bytesRead = in.read(buf)) != -1) { 
    URL u = new URL(defaultURL);
    huc = 
        (HttpURLConnection) u.openConnection();
    huc.setRequestMethod("POST");
    huc.setDoOutput(true);
    huc.setDoInput(true);

    os = huc.getOutputStream();
    os.write(buf, 0, bytesRead);
    os.flush();
    os = null;

    // thanks to dku.rajkumar for the following block of code ! 
    InputStreamReader reader =  
        new InputStreamReader(huc.getInputStream());
    char[] cbuf = new char[400];
    reader.read(cbuf);
    reader.close();

    String s = new String(cbuf);
    messagebuffer.append(s + "\n\n");

    huc.disconnect();

    Thread.sleep(16);
}