UnknownHostException:名称或服务未知

Question

我正在尝试使用com.squareup.okhttp中的OkHttpClient从API返回一些数据.我遇到了一些我最终能够克服的错误,但是我无法通过这个主机异常错误,这里的任何内容似乎都不足以让我的情况能够解决.

下面是我尝试的代码以及它的输出,如果有人知道如何克服错误我会很感激.

码

public void connect() {         
    OkHttpClient client = new OkHttpClient();

    com.squareup.okhttp.Request request = new com.squareup.okhttp.Request.Builder()
    .url("https://socialweb-analytics.lcloud.com/api/public/reports/jobs?companyKey=ato")
    .get()
    .addHeader("authorization", "Basic c2RidXNpbmVzc2FuYWx5dGljc0BhdG8uZ292LmF1OkFuYWx5dGljezEh")
    .addHeader("cache-control", "no-cache")
    .addHeader("postman-token", "65ef5553-77b5-053f-9c01-4fdf76bdc92f")
    .build();

    System.out.println(request.toString());

    try {
        Response response = client.newCall(request).execute();
        System.out.println(response);
    } catch (IOException e) {
        e.printStackTrace();
    }
}

OUTPUT

Request{method=GET, url=https://socialweb-analytics.lcloud.com/api/public/reports/jobs?companyKey=ato, tag=null}
java.net.UnknownHostException: socialweb-analytics.lcloud.com: Name or service not known
    at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
    at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:922)
    at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1314)
    at java.net.InetAddress.getAllByName0(InetAddress.java:1267)
    at java.net.InetAddress.getAllByName(InetAddress.java:1183)
    at java.net.InetAddress.getAllByName(InetAddress.java:1119)
    at com.squareup.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)
    at com.squareup.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:187)
    at com.squareup.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:156)
    at com.squareup.okhttp.internal.http.RouteSelector.next(RouteSelector.java:98)
    at com.squareup.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:344)
    at com.squareup.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:327)
    at com.squareup.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:245)
    at com.squareup.okhttp.Call.getResponse(Call.java:267)
    at com.squareup.okhttp.Call$ApplicationInterceptorChain.proceed(Call.java:224)
    at com.squareup.okhttp.Call.getResponseWithInterceptorChain(Call.java:195)
    at com.squareup.okhttp.Call.execute(Call.java:79)
    at technical_services.persistence.lithium.LithiumDataStore.connect1(LithiumDataStore.java:127)
    at application.lithium_etl.LithiumTestController.main(LithiumTestController.java:24)

Answer 1

对于像"java.net.UnknownHostException:[hostname]"这样的错误

原因是你的主机名不在/ etc/hosts中,解决方案很简单:

sudo vim /etc/hosts

改变线看起来像:

127.0.0.1  localhost

至:

127.0.0.1  [hostname] localhost

保存并退出.如果问题仍然存在,可能需要重启或运行:

sudo ifconfig eth0 down&&sudo ifconfig eth0 up

希望它可以帮到你!

Answer 2

扩展 zhenbo xu 的精彩回答，这是我sed在 EC2 中使用自动化所做的工作。

sudo sed -i -e '/127.0.0.1/ s/\(localhost\)/'$(hostname)' \1/' /etc/hosts

请注意，为了允许变量扩展，单引号结束并围绕 subshel​​l 调用重新启动。

hostname 是某些 Linux 系统上的可执行文件（但可能不是全部，因此您可以改用环境变量，或删除子 shell 周围的引号并使用静态字符串）。

这\1很sed神奇，它将转义括号中的“捕获”搜索字符串（s/search/replacement/）放回替换字符串中。

Answer 3

由于您还没有发布您的代码connect()，因此请参考我的以下工作代码

    private class StringRequest extends AsyncTask<Void, Void, String> {
        @Override
        protected String doInBackground(Void... voids) {
            OkHttpClient client = new OkHttpClient();
            Request request = new Request.Builder()
                    .url("https://socialweb-analytics.lcloud.com/api/public/reports/jobs?companyKey=ato")
                    .addHeader("authorization", "Basic c2RidXNpbmVzc2FuYWx5dGljc0BhdG8uZ292LmF1OkFuYWx5dGljezEh")
                    .addHeader("cache-control", "no-cache")
                    .addHeader("postman-token", "65ef5553-77b5-053f-9c01-4fdf76bdc92f")
                    .build();
            try {
                Response response = client.newCall(request).execute();
                return response.body().string();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }
        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            System.out.println(s);
        }
    }

然后在onCreate里面：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mTextView = (TextView) findViewById(R.id.textView);
    new StringRequest().execute();
}

我的应用程序运行并得到以下结果（可能是因为令牌过期/无效）：

I/System.out: {"code":500,"message":"There was an error processing your request. It has been logged (ID a2f28b587b2f9dcc)."}

P/S: 确保你已经设置了<uses-permission android:name="android.permission.INTERNET" />内部AndroidManifest.xml文件