java8 stream 按对象属性 多属性字段排序
按多字段排序::
Comparator<VO> bya = Comparator.comparing(VO::getAppId).reversed();//按照a升序
Comparator<VO> byb = Comparator.comparing(VO::getNum).reversed();//按照b降序
Collections.sort(resultlist,bya.thenComparing(byb));
按单字段降序排序
Collections.sort(resultlist,(a, b)->b.getNum().compareTo(a.getNum()));