Map

自定义类型作为键的时候一定要重写hashcode和equals方法,让他自动生成即可.不然是不能作为键的,会爆炸.

map面试题

https://mp.weixin.qq.com/s?__biz=Mzg2NDA4MzIxMQ==&mid=100000069&idx=1&sn=216341a60d507a53fc9467ec4a7bffff&chksm=4e6f8d217918043759441cf8ad3455d6d7c7150a9c0caf6c7cb832113133dfccc50bbc7e02c4&mpshare=1&scene=23&srcid=0826hy9DOQspTqw6ETcMsYAK&sharer_sharetime=1566834059637&sharer_shareid=739fe531d4e491356d98f4cae93fcc17#rd

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https://www.cnblogs.com/wangxilei/p/9272508.html

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https://blog.csdn.net/u014514383/article/details/88796955

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https://blog.csdn.net/fang0321/article/details/83857458