android OkHttpClient请求错误

我正在尝试使用我的 Android 应用程序在 mysql 数据库中存储一些数据。我正在使用 okhttp3 发送请求，但在这一行出现错误：

client.newCall(request).execute();

我在本地机器和在线上尝试过，但它给了我同样的错误，这里是代码，

public class MainActivity extends AppCompatActivity {

    String token1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        System.out.println("MainActivity is :" + FirebaseInstanceId.getInstance().getToken());
        FirebaseMessaging.getInstance().subscribeToTopic("test");
        FirebaseInstanceId.getInstance().getToken();
        token1=FirebaseInstanceId.getInstance().getToken();
    }

    public void clicking(View view) {

        OkHttpClient client = new OkHttpClient();
        RequestBody body = new FormBody.Builder()
                .add("Token",token1)
                .build();

        okhttp3.Request request = new okhttp3.Request.Builder()
                .url("http://saleh923.byethost8.com/hii.html")
                .post(body)
                .build();

        try {
            client.newCall(request).execute();
        } catch (IOException e) {

            e.printStackTrace();
        }
    }
}

这是日志：

 com.example.user.firebasenot E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.user.firebasenot, PID: 3280
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
        at android.view.View.performClick(View.java:5198)
        at android.view.View$PerformClick.run(View.java:21147)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5417)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
        at android.view.View.performClick(View.java:5198) 
        at android.view.View$PerformClick.run(View.java:21147) 
        at android.os.Handler.handleCallback(Handler.java:739) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:148) 
        at android.app.ActivityThread.main(ActivityThread.java:5417) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
     Caused by: android.os.NetworkOnMainThreadException
        at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
        at java.net.InetAddress.lookupHostByName(InetAddress.java:431)
        at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
        at java.net.InetAddress.getAllByName(InetAddress.java:215)
        at okhttp3.Dns$1.lookup(Dns.java:39)
        at okhttp3.internal.connection.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:172)
        at okhttp3.internal.connection.RouteSelector.nextProxy(RouteSelector.java:138)
        at okhttp3.internal.connection.RouteSelector.next(RouteSelector.java:80)
        at okhttp3.internal.connection.StreamAllocation.findConnection(StreamAllocation.java:178)
        at okhttp3.internal.connection.StreamAllocation.findHealthyConnection(StreamAllocation.java:129)
        at okhttp3.internal.connection.StreamAllocation.newStream(StreamAllocation.java:98)
        at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:42)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:109)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:124)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:170)
        at okhttp3.RealCall.execute(RealCall.java:60)
        at com.example.user.firebasenot.MainActivity.clicking(MainActivity.java:54)
        at java.lang.reflect.Method.invoke(Native Method) 
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
        at android.view.View.performClick(View.java:5198) 
        at android.view.View$PerformClick.run(View.java:21147) 
        at android.os.Handler.handleCallback(Handler.java:739) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:148) 
        at android.app.ActivityThread.main(ActivityThread.java:5417) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

错误消息说明了一切：

引起原因：android.os.NetworkOnMainThreadException

您不应该在主（也称为 UI）线程上发出网络请求。
您可以通过多种方式在不同的线程上发出此请求，以下是其中一种：

final OkHttpClient client = new OkHttpClient();
RequestBody body = new FormBody.Builder()
        .add("Token",token1)
        .build();

final okhttp3.Request request = new okhttp3.Request.Builder()
        .url("http://saleh923.byethost8.com/hii.html")
        .post(body)
        .build();

final Thread thread = new Thread(new Runnable() {
    @Override
    public void run() {
        try {
            client.newCall(request).execute();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
});

But okhttp使我们可以更轻松地使用入队方法 https://square.github.io/okhttp/3.x/okhttp/okhttp3/Call.html#enqueue-okhttp3.Callback-:

client.newCall(request).enqueue(new Callback() {
    @Override
    public void onFailure(Call call, IOException e) {
        e.printStackTrace();
    }

    @Override
    public void onResponse(Call call, final Response response) throws IOException {
        if (!response.isSuccessful()) {
            throw new IOException("Unexpected code " + response);
        }

        // you code to handle response
    }
);