Thread 类中存在变量 :
```
ThreadLocal.ThreadLocalMapthreadLocals =null;
```
关于源码：get()方法：
/**
* Returns the value in the current thread's copy of this
* thread-local variable. If the variable has no value for the
* current thread, it is first initialized to the value returned
* by an invocation of the {@link#initialValue} method.
*
*@returnthe current thread's value of this thread-local
*/
publicTget() {
Thread t = Thread.currentThread();
ThreadLocalMap map = getMap(t);
if(map !=null) {
ThreadLocalMap.Entry e = map.getEntry(this);
if(e !=null)
return(T)e.value;
}
returnsetInitialValue();
}
这里getMap(t)实现：
ThreadLocalMap getMap(Thread t) {
returnt.threadLocals;
}
参考地址：http://blog.csdn.net/lufeng20/article/details/24314381
