okHttp的一个工具类

要封装一个OKttp的有个工具类，下面是工具类的代码

public class OkHttp3Util {    /**     * 懒汉 安全 加同步     * 私有的静态成员变量 只声明不创建     * 私有的构造方法     * 提供返回实例的静态方法     */    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 sdcache = 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(sdcache.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));            Log.d("++++++++++++++",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);    }    /**     * post请求上传文件....包括图片....流的形式传任意文件...     * 参数1 url     * file表示上传的文件     * fileName....文件的名字,,例如aaa.jpg     * params ....传递除了file文件 其他的参数放到map集合     *     */    public static void uploadFile(String url, File file, String fileName,Map<String,String> params) {        //创建OkHttpClient请求对象        OkHttpClient okHttpClient = getInstance();        MultipartBody.Builder builder = new MultipartBody.Builder();        builder.setType(MultipartBody.FORM);        //参数        if (params != null){            for (String key : params.keySet()){                builder.addFormDataPart(key,params.get(key));            }        }        //文件...参数name指的是请求路径中所接受的参数...如果路径接收参数键值是fileeeee,此处应该改变        builder.addFormDataPart("file",fileName,RequestBody.create(MediaType.parse("application/octet-stream"),file));        //构建        MultipartBody multipartBody = builder.build();        //创建Request        Request request = new Request.Builder().url(url).post(multipartBody).build();        //得到Call        Call call = okHttpClient.newCall(request);        //执行请求        call.enqueue(new Callback() {            @Override            public void onFailure(Call call, IOException e) {            }            @Override            public void onResponse(Call call, Response response) throws IOException {                //上传成功回调 目前不需要处理                if (response.isSuccessful()){                    String s = response.body().string();                    com.orhanobut.logger.Logger.e("上传--"+s);                }            }        });    }    /**     * Post请求发送JSON数据....{"name":"zhangsan","pwd":"123456"}     * 参数一：请求Url     * 参数二：请求的JSON     * 参数三：请求回调     */    public static void doPostJson(String url, String jsonParams, Callback callback) {        RequestBody requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), jsonParams);        Request request = new Request.Builder().url(url).post(requestBody).build();        Call call = getInstance().newCall(request);        call.enqueue(callback);    }    /**     * 下载文件 以流的形式把apk写入的指定文件 得到file后进行安装     * 参数er：请求Url     * 参数san：保存文件的文件夹....download     */    public static void download(final Activity context, final String url, final String saveDir) {        Request request = new Request.Builder().url(url).build();        Call call = getInstance().newCall(request);        call.enqueue(new Callback() {            @Override            public void onFailure(Call call, IOException e) {                com.orhanobut.logger.Logger.e(e.getLocalizedMessage());            }            @Override            public void onResponse(Call call, final Response response) throws IOException {                InputStream is = null;                byte[] buf = new byte[2048];                int len = 0;                FileOutputStream fos = null;                try {                    is = response.body().byteStream();//以字节流的形式拿回响应实体内容                    //apk保存路径                    final String fileDir = isExistDir(saveDir);                    //文件                    File file = new File(fileDir, getNameFromUrl(url));                    fos = new FileOutputStream(file);                    while ((len = is.read(buf)) != -1) {                        fos.write(buf, 0, len);                    }                    fos.flush();                    context.runOnUiThread(new Runnable() {                        @Override                        public void run() {                            Toast.makeText(context, "下载成功:" + fileDir + "," + getNameFromUrl(url), Toast.LENGTH_SHORT).show();                        }                    });                    //apk下载完成后 调用系统的安装方法                    Intent intent = new Intent(Intent.ACTION_VIEW);                    intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");                    context.startActivity(intent);                } catch (IOException e) {                    e.printStackTrace();                } finally {                    if (is != null) is.close();                    if (fos != null) fos.close();                }            }        });    }    /**     * 判断下载目录是否存在......并返回绝对路径     *     * @param saveDir     * @return     * @throws IOException     */    public static String isExistDir(String saveDir) throws IOException {        // 下载位置        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {            File downloadFile = new File(Environment.getExternalStorageDirectory(), saveDir);            if (!downloadFile.mkdirs()) {                downloadFile.createNewFile();            }            String savePath = downloadFile.getAbsolutePath();            Log.e("savePath", savePath);            return savePath;        }        return null;    }    /**     * @param url     * @return 从下载连接中解析出文件名     */    private static String getNameFromUrl(String url) {        return url.substring(url.lastIndexOf("/") + 1);    }}