android - 我对android上的HttpURLConnections的疑问。 (cast-URLConnection，url.openConnection，getOutPutStream()。)

我在创建httpurlconnection（或httpsurlconnection）时遇到问题。其实这是关于在转换url.openconnection之后设置连接头的信息。我听不懂（例外：已经连接...或类似。）

有时它会一直运行到httpConn.getOutPutStream（）;。此时，它给出错误“ java.net.ProtocolException：OutputStream不可用，因为请求头已经发送！”

我的错在哪里？

在我使用代码之前：所有代码都是here（我也有一个关于This Code的问题）

URL url = new URL(getUrl());
URLConnection conn = url.openConnection();
HttpURLConnection httpConn=(HttpURLConnection)conn; /*or HttpsURLConnection*/
httpConn.set...
...
httpConn.connect();
...

我尝试在投放后设置一些设置，但结果是相同的。 conn.set ..可以正常工作，但是在投射后我什么都不能设置...

更改的代码：

        URL url = new URL(getUrl());
        conn = url.openConnection();
        conn.setAllowUserInteraction(false);
        conn.setConnectTimeout(10000);
        conn.setRequestProperty("Accept-Charset", "utf-8");
        conn.setRequestProperty("Content-Type",
                "text/xml; charset=utf-8");
        conn.setRequestProperty("SOAPAction",
                "http://tempuri.org/IAuthenticationServiceNew/Authenticate");
        conn.setRequestProperty("Software-Version", AppData.VERSION);
        conn.setDoOutput(true);
        httpConn = (HttpsURLConnection) conn;
        httpConn.setChunkedStreamingMode(getParams().getBytes("UTF8").length);
        httpConn.setInstanceFollowRedirects(true);

        httpConn.connect();
        os = httpConn.getOutputStream();
        os.write(getParams().getBytes("UTF8"));

最佳答案

这是正确的！
         “ httpConn.setInstanceFollowRedirects（true）”连接并将标头发送到服务器。我关闭此代码。

        URL url = new URL(getUrl());
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setDoInput(true);
        httpConn.setDoOutput(true);
        httpConn.setAllowUserInteraction(false);
        httpConn.setUseCaches(false);
        httpConn.setConnectTimeout(10000);
        httpConn.setRequestProperty("Accept-Charset", "utf-8");
        httpConn.setRequestProperty("Content-Type",
                "text/xml; charset=utf-8");
        httpConn.setRequestProperty("SOAPAction",
                "http://tempuri.org/IAuthenticationServiceNew/"
                        + conTypeString);
        httpConn.setRequestProperty("Software-Version", AppData.VERSION);
        httpConn.setRequestMethod("POST");
        httpConn.setChunkedStreamingMode(0);
        os = httpConn.getOutputStream();
        os.write(getParams().getBytes("UTF8"));