多线程-ThreadLocal
标签：except 线程安全 使用 stat 安全 rri sys ati over
1.threadLocal：本地线程变量，为每个线程提供副本，以此来保证线程安全。
2.性能：从并发的角度来说，如果并发量不是很大，加锁的方式会更好。并发量很大的情况下，使用threadlocal可以一定程度减小所竞争。
3.举个栗子：
public class test005_threadlocal {
public static void main(String[] args) {
ThreadLocal threadLocal = new ThreadLocal();//
People p = new People();//
//主线程
threadLocal.set(new People(9));
p.setAge(999);
Thread t1 = new Thread(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(0);
threadLocal.set(new People(111));
p.setAge(1);
System.out.println("t1-threadLocal:" + threadLocal.get().getAge());//输出的肯定是111
System.out.println("t1-p:" + p.getAge());//输出的不一定是1
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
Thread t2 = new Thread(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(0);
threadLocal.set(new People(222));
p.setAge(2);
System.out.println("t2-threadLocal:" + threadLocal.get().getAge());
System.out.println("t2-p:" + p.getAge());
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
Thread t3 = new Thread(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(0);
threadLocal.set(new People(333));
p.setAge(3);
System.out.println("t3-threadLocal:" + threadLocal.get().getAge());
System.out.println("t3-p:" + p.getAge());
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
System.out.println("main-threadLocal:" + threadLocal.get().getAge());
System.out.println("main-p:" + p.getAge());
System.out.println("----------------------------");
t1.start();
t2.start();
t3.start();
}
}
看到了threadlocal来保证线程安全的本质了吗？代码中有，自己找。
多线程-ThreadLocal
标签：except 线程安全 使用 stat 安全 rri sys ati over
原文地址：https://www.cnblogs.com/mianduijifengba/p/9597622.html
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