改造无法连接到端口 3000 上的本地 Web 服务器

Question

我使用 Retrofit (v1.6.1) 连接到 REST Web 服务的应用无法连接到我的本地 Web 服务器（在 localhost 上运行），这是我遇到的错误。

这是在 Nexus4 (v4.3) 模拟器中，我使用 Android Studio 进行开发，并在清单文件中添加了 android.permission.INTERNET 和 android.permission.ACCESS_NETWORK_STATE 权限。

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.access$100(RestAdapter.java:220)
            at retrofit.RestAdapter$RestHandler$2.obtainResponse(RestAdapter.java:278)
            at retrofit.CallbackRunnable.run(CallbackRunnable.java:42)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
            at retrofit.Platform$Android$2$1.run(Platform.java:142)
            at java.lang.Thread.run(Thread.java:841)
     Caused by: libcore.io.ErrnoException: isConnected failed: ECONNREFUSED (Connection refused)
            at libcore.io.IoBridge.isConnected(IoBridge.java:208)
            at libcore.io.IoBridge.connectErrno(IoBridge.java:161)
            at libcore.io.IoBridge.connect(IoBridge.java:112)
            at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
            at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
            at java.net.Socket.connect(Socket.java:842)
            at libcore.net.http.HttpConnection.<init>(HttpConnection.java:76)
            at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
            at libcore.net.http.HttpConnection$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.access$100(RestAdapter.java:220)
            at retrofit.RestAdapter$RestHandler$2.obtainResponse(RestAdapter.java:278)
            at retrofit.CallbackRunnable.run(CallbackRunnable.java:42)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
            at retrofit.Platform$Android$2$1.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

Answer 1

在您的手机上连接到localhost:3000 表示“连接到本地网络接口上的端口 3000” - 这是手机的本地接口，而不是您的手机所连接的 PC 的端口 3000。手机的 3000 端口没有监听，所以出现连接被拒绝错误。

您想要做的是（可能，如果没有更多信息，很难猜到）是从手机连接到您 PC 上的端口 3000。因此，您应该将要连接的地址从 localhost 更改为 PC 的地址。如果模拟器是 10.0.2.2 （这是 PC 的本地主机）。 See networking information供参考。

Answer 2

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。

在这里找到它 - http://developer.android.com/tools/devices/emulator.html#networkaddresses