使用Retrofit（v1.6.1）连接到REST Web服务的我的应用程序无法连接到我的本地Web服务器（在localhost上运行），这是我得到的错误。
这是在Nexus4（v4.3）模拟器中，我正在使用Android Studio进行开发，我添加了android.permission.INTERNET＆amp;清单文件中的android.permission.ACCESS_NETWORK_STATE权限。
错误说它等了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
答案 0 :(得分：44)
在手机上连接到localhost:3000表示＆＃34;连接到本地网络接口上的端口3000＆＃34; - 这是手机的本地接口，而不是手机所连接的PC的端口3000。手机上的端口3000没有任何监听，因此您会收到连接拒绝错误。
你试图做的事情（可能很难在没有更多信息的情况下猜测）是从手机连接到你电脑上的端口3000。因此，您应该将您要连接的地址从localhost更改为PC的地址。如果模拟器是 10.0.2.2 （它是PC的localhost）。 See networking information供参考。
答案 1 :(得分：28)
我解决了这个问题，需要使用10.0.2.2代替localhost连接到我的本地服务器。
在此处找到它 - http://developer.android.com/tools/devices/emulator.html#networkaddresses