//移除檔案，獲取檔案時間與當前時間對比，我這時間定位5天，刪除五天前的檔案
public static void removeFileByTime(String dirPath) {
        //獲取目錄下所有檔案
        List<File> allFile = getDirAllFile(new File(dirPath));
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm");
        //獲取當前時間
        Date end = new Date(System.currentTimeMillis());
        try {
            end = dateFormat.parse(dateFormat.format(new Date(System.currentTimeMillis())));
        } catch (Exception e){
            Log.d(TAG, "dataformat exeption e " + e.toString());
        }
        Log.d(TAG, "getNeedRemoveFile  dirPath = "  +dirPath);
        for (File file : allFile) {//ComDef
            try {
                //檔案時間減去當前時間
                Date start = dateFormat.parse(dateFormat.format(new Date(file.lastModified())));
                long diff = end.getTime() - start.getTime();//這樣得到的差值是微秒級別
                long days = diff / (1000 * 60 * 60 * 24);
                if(ComDef.LOGMAXKEEPTIME <= days){
                    deleteFile(file);
                }

            } catch (Exception e){
                Log.d(TAG, "dataformat exeption e " + e.toString());
            }
        }
    }

    //刪除資料夾及資料夾下所有檔案
    public static void deleteFile(File file) {
        if (file.isDirectory()) {
            File[] files = file.listFiles();
            for (int i = 0; i < files.length; i++) {
                File f = files[i];
                deleteFile(f);
            }
            file.delete();
        } else if (file.exists()) {
            file.delete();
        }
    }

    //獲取指定目錄下一級檔案
    public static List<File> getDirAllFile(File file) {
        List<File> fileList = new ArrayList<>();
        File[] fileArray = file.listFiles();
        if(fileArray == null)
            return fileList;
        for (File f : fileArray) {
            fileList.add(f);
        }
        fileSortByTime(fileList);
        return fileList;
    }

    //對檔案進行時間排序
    public static void fileSortByTime(List<File> fileList) {
        Collections.sort(fileList, new Comparator<File>() {
            public int compare(File p1, File p2) {
                if (p1.lastModified() < p2.lastModified()) {
                    return -1;
                }
                return 1;
            }
        });
    }