Android Retrofit 无法通过端口 3000 连接到我的本地 Web 服务器
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Retrofit cannot connect to my local web server on port 3000
提问by kapso
My app that is using Retrofit (v1.6.1) to connect to REST web services cannot connect to my local web server (running on localhost), this is the error I am getting.
我使用 Retrofit (v1.6.1) 连接到 REST Web 服务的应用程序无法连接到我的本地 Web 服务器（在 上运行localhost），这是我收到的错误。
This is inside Nexus4 (v4.3) emulator, I am using Android Studio for development and I have added android.permission.INTERNET& android.permission.ACCESS_NETWORK_STATEpermissions in manifest file.
这是在 Nexus4 (v4.3) 模拟器中，我使用 Android Studio 进行开发，并且在清单文件中添加了android.permission.INTERNET&android.permission.ACCESS_NETWORK_STATE权限。
The error says its waited for 15s but it does not, it errors out right away.
错误说它等待了 15 秒但它没有，它立即出错。
07-13 15:57:53.947 820-840/it.test.android.app.activity D/Retrofit﹕ ---> HTTP POST http://localhost:3000/app/auth/signin
07-13 15:57:54.132 820-840/it.test.android.app.activity D/Retrofit﹕ Content-Type: application/json; charset=UTF-8
07-13 15:57:54.132 820-840/it.test.android.app.activity D/Retrofit﹕ Content-Length: 44
07-13 15:57:54.157 820-840/it.test.android.app.activity D/Retrofit﹕ {"auth":{"email":"steve","password":"pass"}}
07-13 15:57:54.387 820-840/it.test.android.app.activity D/Retrofit﹕ ---> END HTTP (44-byte body)
07-13 15:57:54.657 820-840/it.test.android.app.activity D/Retrofit﹕ ---- ERROR http://localhost:3000/app/auth/signin
07-13 15:57:54.857 820-840/it.test.android.app.activity D/Retrofit﹕ java.net.ConnectException: failed to connect to localhost/127.0.0.1 (port 3000) after 15000ms: isConnected failed: ECONNREFUSED (Connection refused)
at libcore.io.IoBridge.isConnected(IoBridge.java:223)
at libcore.io.IoBridge.connectErrno(IoBridge.java:161)
at libcore.io.IoBridge.connect(IoBridge.java:112)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
at java.net.Socket.connect(Socket.java:842)
at libcore.net.http.HttpConnection.<init>(HttpConnection.java:76)
at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316)
at libcore.net.http.HttpEngine.connect(HttpEngine.java:311)
at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290)
at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240)
at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:81)
at libcore.net.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:197)
at retrofit.client.UrlConnectionClient.prepareRequest(UrlConnectionClient.java:68)
at retrofit.client.UrlConnectionClient.execute(UrlConnectionClient.java:37)
at retrofit.RestAdapter$RestHandler.invokeRequest(RestAdapter.java:321)
at retrofit.RestAdapter$RestHandler.access0(RestAdapter.java:220)
at retrofit.RestAdapter$RestHandler.obtainResponse(RestAdapter.java:278)
at retrofit.CallbackRunnable.run(CallbackRunnable.java:42)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
at retrofit.Platform$Android.run(Platform.java:142)
at java.lang.Thread.run(Thread.java:841)
Caused by: libcore.io.ErrnoException: isConnected failed: ECONNREFUSED (Connection refused)
at libcore.io.IoBridge.isConnected(IoBridge.java:208)
????????????at libcore.io.IoBridge.connectErrno(IoBridge.java:161)
????????????at libcore.io.IoBridge.connect(IoBridge.java:112)
????????????at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
????????????at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
????????????at java.net.Socket.connect(Socket.java:842)
????????????at libcore.net.http.HttpConnection.<init>(HttpConnection.java:76)
????????????at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
????????????at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
????????????at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
????????????at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
????????????at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316)
????????????at libcore.net.http.HttpEngine.connect(HttpEngine.java:311)
????????????at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290)
????????????at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240)
????????????at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:81)
????????????at libcore.net.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:197)
????????????at retrofit.client.UrlConnectionClient.prepareRequest(UrlConnectionClient.java:68)
????????????at retrofit.client.UrlConnectionClient.execute(UrlConnectionClient.java:37)
????????????at retrofit.RestAdapter$RestHandler.invokeRequest(RestAdapter.java:321)
????????????at retrofit.RestAdapter$RestHandler.access0(RestAdapter.java:220)
????????????at retrofit.RestAdapter$RestHandler.obtainResponse(RestAdapter.java:278)
????????????at retrofit.CallbackRunnable.run(CallbackRunnable.java:42)
????????????at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
????????????at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
????????????at retrofit.Platform$Android.run(Platform.java:142)
????????????at java.lang.Thread.run(Thread.java:841)
07-13 15:57:54.857 820-840/it.test.android.app.activity D/Retrofit﹕ ---- END ERROR
回答by Mariusz Jamro
On your phone connecting to localhost:3000means "connect to port 3000 on local network interface" - which is local interface of the phone, not the port 3000 of the PC to which your phone is connected. There is nothing listening on port 3000 on the phone, so you get connection refused error.
在您的手机上连接localhost:3000意味着“连接到本地网络接口上的端口 3000” - 这是手机的本地接口，而不是手机连接到的 PC 的端口 3000。手机上的端口 3000 没有任何监听，因此您会收到连接被拒绝的错误。
Whould you're trying to do is (probably, hard to guess without more information) is to connect from the phone to port 3000 on you PC. So you should change the address you're connecting to from localhostto address of the PC. In case of emulator that would be 10.0.2.2(which is localhost of the PC). See networking informationfor reference.
你想要做的是（可能，没有更多信息就很难猜测）是从手机连接到你电脑上的端口 3000。因此，您应该将要连接的地址更改localhost为 PC 的地址。在模拟器的情况下，这将是10.0.2.2（这是 PC 的本地主机）。请参阅网络信息以供参考。
回答by kapso
I solved the issue, need to use 10.0.2.2instead of localhostto connect to my local server.
我解决了这个问题，需要使用10.0.2.2而不是localhost连接到我的本地服务器。
Found it here - http://developer.android.com/tools/devices/emulator.html#networkaddresses
在这里找到 - http://developer.android.com/tools/devices/emulator.html#networkaddresses
