public class OkHttpUtil {
    public static void RequestData(String address,final HttpCallBackListener listener){
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder().url(address).build();
        client.newCall(request).enqueue(listener);
        //异步方式
    }
}

public interface HttpCallBackListener {
     void onFinish(String respose);
     void onError(Exception e);
}

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        OkHttpUtil.requestData("请求的网址", new HttpCallBackListener() {
            @Override
            public void onFinish(String respose) {
                //处理请求
            }
            @Override
            public void onError(Exception e) {
                //处理异常
            }
        });
    }
}