Threadlocal这种数据结构总是忘？那就好好写一篇关于它的

还是用图说话吧，对看图最简单。知道几个概念的关系，一切就顺理成章的记住了。

threadlocal related.png

Threadlocal.get>
Thread.threadLocals.getEntry>
ThreadLocalMap.table[ special i by threadlocal]>
retrun entry.value

ThreadLocal.set(value)>
Thread.threadLocals.set( threadlocal ,value)>
find or create entry(new entry(threadlocal,vale)) by special i (table[i])