okhttp3封装

public class OkHttpUtils {    private Handler handler = new Handler();    public Handler getHandler(){        return handler;    }    //单例    private static OkHttpUtils okHttpUtils = new OkHttpUtils();    private OkHttpUtils(){};    public static OkHttpUtils getInstance(){        return okHttpUtils;    }    private OkHttpClient client;    private void initOkHttpClient(){        if(client == null){            client = new OkHttpClient.Builder().build();        }    }    //公用的get请求方法  完成的功能不确定    public void doGet(String url, Callback callback){        initOkHttpClient();        Request request = new Request.Builder().url(url).build();        Call call = client.newCall(request);        call.enqueue(callback);    }}