[Java123] HashMap实现和应用

https://www.cnblogs.com/mzc-blogs/p/5800084.html

PUT函数-如果节点已经存在就替换old value(保证key的唯一性)

https://www.jianshu.com/p/bbcf413b8332

https://www.cnblogs.com/aotian/p/9491346.html

https://segmentfault.com/q/1010000008389334

https://www.cnblogs.com/chongyou/p/9126101.html