加锁和解锁
我们来看下ReentrantLock的基本用法
ThreadDomain35类
public class ThreadDomain35 {
private Lock lock = new ReentrantLock();
public void testMethod()
{
try
{
lock.lock();
for (int i = 0; i < 2; i++)
{
System.out.println("ThreadName = " + Thread.currentThread().getName() + ", i = " + i);
}
}
finally
{
lock.unlock();
}
}
}
线程和main方法
public class MyThread35 extends Thread {
private ThreadDomain35 td;
public MyThread35(ThreadDomain35 td)
{
this.td = td;
}
public void run()
{
td.testMethod();
}
public static void main(String[] args)
{
ThreadDomain35 td = new ThreadDomain35();
MyThread35 mt0 = new MyThread35(td);
MyThread35 mt1 = new MyThread35(td);
MyThread35 mt2 = new MyThread35(td);
mt0.start();
mt1.start();
mt2.start();
}
}
输出结果
ThreadName = Thread-2, i = 0 ThreadName = Thread-2, i = 1 ThreadName = Thread-0, i = 0 ThreadName = Thread-0, i = 1 ThreadName = Thread-1, i = 0 ThreadName = Thread-1, i = 1
一个线程必须执行完才能执行下一个线程，说明ReentrantLock可以加锁。
ReentrantLock持有的对象监视器和synchronized不同
ThreadDomain37类,methodB用synchronized修饰
public class ThreadDomain37 {
private Lock lock = new ReentrantLock();
public void methodA()
{
try
{
lock.lock();
System.out.println("MethodA begin ThreadName = " + Thread.currentThread().getName());
Thread.sleep(5000);
System.out.println("MethodA end ThreadName = " + Thread.currentThread().getName());
}
catch (InterruptedException e)
{
e.printStackTrace();
}
finally
{
lock.unlock();
}
}
public synchronized void methodB()
{
System.out.println("MethodB begin ThreadName = " + Thread.currentThread().getName());
System.out.println("MethodB begin ThreadName = " + Thread.currentThread().getName());
}
}
MyThread37_0类
public class MyThread37_0 extends Thread {
private ThreadDomain37 td;
public MyThread37_0(ThreadDomain37 td)
{
this.td = td;
}
public void run()
{
td.methodA();
}
}
MyThread37_1类
public class MyThread37_1 extends Thread {
private ThreadDomain37 td;
public MyThread37_1(ThreadDomain37 td)
{
this.td = td;
}
public void run()
{
td.methodB();
}
}
MyThread37_main方法
public class MyThread37_main {
public static void main(String[] args)
{
ThreadDomain37 td = new ThreadDomain37();
MyThread37_0 mt0 = new MyThread37_0(td);
MyThread37_1 mt1 = new MyThread37_1(td);
mt0.start();
mt1.start();
}
}
运行结果如下
MethodA begin ThreadName = Thread-0 MethodB begin ThreadName = Thread-1 MethodB begin ThreadName = Thread-1 MethodA end ThreadName = Thread-0
加了synchronized依然是异步执行，说明Reentra本文来源gao@!dai!ma.com搞$$代^@码5网@ntLock和synchronized持有的对象监视器不同。ReentrantLock需要手动加锁和释放锁。
Condition
基本用法
synchronized与wait()和nitofy()/notifyAll()方法可以实现等待/唤醒模型，ReentrantLock同样可以，需要借助Condition的await()和signal/signalAll()，await()释放锁。
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转载请注明原文链接：Java多线程 ReentrantLock互斥锁详解
转载请注明原文链接：Java多线程 ReentrantLock互斥锁详解
