封装OkHttp的方法

创建一个类 OkHttpUtils
public class OkHttpUtils{
      private static OkHttpClient okHttpClient;

    //get请求
    public static void doGet(String url, Callback callback)
    {
        OkHttpClient okHttpClient=getInstance();
        //创建Request
        Request request=new Request.Builder()
                .url(url)
                .build();
        Call call=okHttpClient.newCall(request);
        call.enqueue(callback);
    }
    //post请求
    public static void doPost(String url, Map params, Callback callback)
    {
        OkHttpClient okHttpClient=getInstance();

        FormBody.Builder builder=new FormBody.Builder();
		if(params!=null)
        {
			for(String key:params.keySet())
			{
				builder.add(key,params.get(key));
			}
		}

        Request request=new Request.Builder()
                .post(builder.build())
                .url(url)
                .build();

        Call call=okHttpClient.newCall(request);
        call.enqueue(callback);
    }
}