连接服务器请求 GET 错误 java.net.ProtocolException

[初级程序猿洪国强]

// 创建URL
				URL url = new URL(urlPath);
				Log.i(TAG, "startDowload  url -------->" + url);

				// 创建HttpURLConnection对象
				HttpURLConnection conn = (HttpURLConnection) url
						.openConnection();
				Log.i(TAG, "startDowload  conn.getResponseCode() -------->"
						+ conn.getResponseCode());
				Log.i(TAG, "startDowload  conn -------->" + conn);
				// 设置连接超时
				conn.setConnectTimeout(3000);
				// 设置连接方式
				conn.setRequestMethod("GET");

报错误
07-28 09:22:41.460: WARN/System.err(18194): java.net.ProtocolException: Connection already established
07-28 09:22:41.480: WARN/System.err(18194): at java.net.HttpURLConnection.setRequestMethod(HttpURLConnection.java:429)
07-28 09:22:41.480: WARN/System.err(18194): at com.hgq.download.server.Downloader.startDowload(Downloader.java:82)
07-28 09:22:41.480: WARN/System.err(18194): at com.hgq.download.MainActivity.startDownload(MainActivity.java:115)
07-28 09:22:41.490: WARN/System.err(18194): at com.hgq.download.MainActivity.onClick(MainActivity.java:84)
07-28 09:22:41.490: WARN/System.err(18194): at android.view.View.performClick(View.java:2408)
07-28 09:22:41.490: WARN/System.err(18194): at android.view.View$PerformClick.run(View.java:8816)
07-28 09:22:41.490: WARN/System.err(18194): at android.os.Handler.handleCallback(Handler.java:587)
07-28 09:22:41.500: WARN/System.err(18194): at android.os.Handler.dispatchMessage(Handler.java:92)
07-28 09:22:41.500: WARN/System.err(18194): at android.os.Looper.loop(Looper.java:123)
07-28 09:22:41.500: WARN/System.err(18194): at android.app.ActivityThread.main(ActivityThread.java:4627)
07-28 09:22:41.500: WARN/System.err(18194): at java.lang.reflect.Method.invokeNative(Native Method)
07-28 09:22:41.500: WARN/System.err(18194): at java.lang.reflect.Method.invoke(Method.java:521)
07-28 09:22:41.510: WARN/System.err(18194): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-28 09:22:41.510: WARN/System.err(18194): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-28 09:22:41.510: WARN/System.err(18194): at dalvik.system.NativeStart.main(Native Method)


请问高手怎么解决吖.?
我连接服务器的代码都这样子的..
一直都没出现问题..就今天出了问题..
好纠结..

[AMinfo]

Log.i(TAG, "startDowload conn.getResponseCode() -------->"
+ conn.getResponseCode());
这段去掉

[wintergoes]

如果没有建立连接并执行getInputStream
在调用getResponseCode的时候，该函数会自动执行getInputStream并获取Response Code
所以你在此函数后再设置Request Type就会造成Connection already established错误。

所以应该改成这样的

...
conn.setRequestMethod("GET");
conn.getInputStream();

                Log.i(TAG, "startDowload  conn.getResponseCode() -------->"
                        + conn.getResponseCode());

conn.getInputStream();获取返回流并已获得ResponseCode

[lyb2518]

将设置连接方式放在创建HttpURLConnection对象下面看看。

                // 创建URL
                URL url = new URL(urlPath);
                Log.i(TAG, "startDowload  url -------->" + url);

                // 创建HttpURLConnection对象
                HttpURLConnection conn = (HttpURLConnection) url
                        .openConnection();
                // 设置连接方式
                conn.setRequestMethod("GET");
                // 设置连接超时
                conn.setConnectTimeout(3000);
                Log.i(TAG, "startDowload  conn.getResponseCode() -------->"
                        + conn.getResponseCode());
                Log.i(TAG, "startDowload  conn -------->" + conn);