封装OKHttp,工具类

public class OkHttp3Util {
    private static OkHttpClient okHttpClient = null;


    private OkHttp3Util() {
    }

    public static OkHttpClient getInstance() {
        if (okHttpClient == null) {
            //加同步安全
            synchronized (OkHttp3Util.class) {
                if (okHttpClient == null) {
                    //okhttp可以缓存数据....指定缓存路径
                    File file = new File(Environment.getExternalStorageDirectory(), "cache");
                    //指定缓存大小
                    int cacheSize = 10 * 1024 * 1024;

                    okHttpClient = new OkHttpClient.Builder()//构建器
                            .connectTimeout(15, TimeUnit.SECONDS)//连接超时
                            .writeTimeout(20, TimeUnit.SECONDS)//写入超时
                            .readTimeout(20, TimeUnit.SECONDS)//读取超时
                           // .cache(new Cache(file.getAbsoluteFile(),cacheSize))//设置缓存
                            .build();
                }
            }

        }

        return okHttpClient;
    }

    /**
     * get请求
     * 参数1 url
     * 参数2 回调Callback
     */

    public static void doGet(String url, Callback callback) {

        //创建OkHttpClient请求对象
        OkHttpClient okHttpClient = getInstance();
        //创建Request
        Request request = new Request.Builder().url(url).build();
        //得到Call对象
        Call call = okHttpClient.newCall(request);
        //执行异步请求
        call.enqueue(callback);


    }

    /**
     * post请求
     * 参数1 url
     * 参数2 Map<String, String> params post请求的时候给服务器传的数据
     *      add..("","")
     *      add()
     */

    public static void doPost(String url, Map<String, String> params, Callback callback) {

        //创建OkHttpClient请求对象
        OkHttpClient okHttpClient = getInstance();
        //3.x版本post请求换成FormBody 封装键值对参数

        FormBody.Builder builder = new FormBody.Builder();
        //遍历集合
        for (String key : params.keySet()) {
            builder.add(key, params.get(key));

        }


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

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

    }

}