Java multithreading 06_ReentrantLock
public class TestLock {
public static void main(String[] args) {
TestLock2 testLock2 = new TestLock2();
new Thread(testLock2).start();
new Thread(testLock2).start();
new Thread(testLock2).start();
}
}
class TestLock2 implements Runnable {
int ticketNums = 10;
@Override
public void run() {
while (true) {
if (ticketNums > 0) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(ticketNums--);
} else {
break;
}
}
}
}
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import java.util.concurrent.locks.ReentrantLock;
public class TestLock {
public static void main(String[] args) {
TestLock2 testLock2 = new TestLock2();
new Thread(testLock2).start();
new Thread(testLock2).start();
new Thread(testLock2).start();
}
}
class TestLock2 implements Runnable{
int ticketNums = 10;
private final ReentrantLock lock = new ReentrantLock();
@Override
public void run() {
while(true) {
lock.lock();
try {
if(ticketNums>0) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(ticketNums--);
}else {
break;
}
} finally {
lock.unlock();
}
}
}
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The comparison of synchronized and Lock:
Lock是显示锁（手动开启和关闭锁，别忘记关闭锁）
synchronized 是隐式锁，出了作用域自动释放
Lock只有代码块锁
synchronized有代码块锁和方法锁
使用 Lock 锁，JVM 将花费较少时间来调度线程，性能更好，并且具有更好的扩展性（提供更多的子类，比如 ReentrantLock）