继承相同基类的不同类型对象,有没有办法进行排序比较 - V2EX
V2EX = way to explore
V2EX 是一个关于分享和探索的地方
Sign Up Now
For Existing Member  Sign In
reidxx
V2EX    Java

继承相同基类的不同类型对象,有没有办法进行排序比较

  •  
  •   reidxx Nov 4, 2019 3383 views
    This topic created in 2377 days ago, the information mentioned may be changed or developed.

    基类 BaseEntity:

    Long id; LocalDateTime createAt; LocalDateTime updateAt; 

    子类 A extends BaseEntity

    子类 B extends BaseEntity

    用泛型可以把 A B 对象塞到一个集合里 List<? super BaseEntity> list。

    现在想对这个集合的元素根据 createAt 字段进行排序,用 Lambda.sort() 无法实现,编译阶段就提示错误了。

    如上,有没有办法可以实现排序呢?

    3 replies    2019-11-04 17:35:04 +08:00
    gaifanking
        1
    gaifanking  
       Nov 4, 2019   1
    直接用 List<BaseEntity>啊
    根据 PECS,不能又 add,又遍历
    cigarzh
        2
    cigarzh  
       Nov 4, 2019
    TreeList 写个 Comparator 行不
    reidxx
        3
    reidxx  
    OP
       Nov 4, 2019
    @anjxue #1 哈哈,我傻了,谢谢大佬,原来根本不需要泛型。。

    @cigarzh #2 一楼方法就行了,谢谢。
    About     Help     Advertise     Blog     API     FAQ     Solana     3195 Online   Highest 6679       Select Language
    创意工作者们的社区
    World is powered by solitude
    VERSION: 3.9.8.5 38ms UTC 00:27 PVG 08:27 LAX 17:27 JFK 20:27
    Do have faith in what you're doing.
    ubao msn snddm index pchome yahoo rakuten mypaper meadowduck bidyahoo youbao zxmzxm asda bnvcg cvbfg dfscv mmhjk xxddc yybgb zznbn ccubao uaitu acv GXCV ET GDG YH FG BCVB FJFH CBRE CBC GDG ET54 WRWR RWER WREW WRWER RWER SDG EW SF DSFSF fbbs ubao fhd dfg ewr dg df ewwr ewwr et ruyut utut dfg fgd gdfgt etg dfgt dfgd ert4 gd fgg wr 235 wer3 we vsdf sdf gdf ert xcv sdf rwer hfd dfg cvb rwf afb dfh jgh bmn lgh rty gfds cxv xcv xcs vdas fdf fgd cv sdf tert sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf shasha9178 shasha9178 shasha9178 shasha9178 shasha9178 liflif2 liflif2 liflif2 liflif2 liflif2 liblib3 liblib3 liblib3 liblib3 liblib3 zhazha444 zhazha444 zhazha444 zhazha444 zhazha444 dende5 dende denden denden2 denden21 fenfen9 fenf619 fen619 fenfe9 fe619 sdf sdf sdf sdf sdf zhazh90 zhazh0 zhaa50 zha90 zh590 zho zhoz zhozh zhozho zhozho2 lislis lls95 lili95 lils5 liss9 sdf0ty987 sdft876 sdft9876 sdf09876 sd0t9876 sdf0ty98 sdf0976 sdf0ty986 sdf0ty96 sdf0t76 sdf0876 df0ty98 sf0t876 sd0ty76 sdy76 sdf76 sdf0t76 sdf0ty9 sdf0ty98 sdf0ty987 sdf0ty98 sdf6676 sdf876 sd876 sd876 sdf6 sdf6 sdf9876 sdf0t sdf06 sdf0ty9776 sdf0ty9776 sdf0ty76 sdf8876 sdf0t sd6 sdf06 s688876 sd688 sdf86