服务器数据json传多了，如何截取

服务器数据传多了，以，为标志进行截取

public PictureCourseWare(String picture, String tag, int nowPage, int allPage) {
        int index = picture.indexOf(",");
        if (index < 0) index = 0;
        Log.e("wy","jpg (,) index =: "+ index);
        Picture = picture.substring(index);
        Tag = tag;
        this.nowPage = nowPage;
        this.allPage = allPage;
    }