threadLocal 入门 保存thread的临时信息 和thread绑定在一起 这个区域不一定要用,但也是不可或缺的存在 /* ThreadLocal values pertaining to this thread. This map is maintained * by the ThreadLocal class. */ //属于这个线程的threadLocal,Map由ThreadLocal来维护 ThreadLocal.ThreadLocalMap threadLocals = null; /* * I…