【读写锁】ReadWriteLock闪亮登场、自己写一个缓存系统

来源：互联网发布：天下3男捏脸大赛数据编辑：程序博客网时间：2024/06/05 02:23

先看一个程序

读与读不互斥、读与写互斥、写与写互斥

与互斥锁相比，读-写锁允许对共享数据进行更高级别的并发访问。

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package xiaozhijingtian;
import java.util.Random;
public class ReadWriteLockTest {
public static void main(String[] args) {
final ReadWriteObject object=new ReadWriteObject();
for(int i=0;i<3;i++)
{
new Thread(){
public void run() {
while(true)
object.read();
};
}.start();
new Thread(){
public void run() {
while(true)
object.write(new Random().nextInt(10));
};
}.start();
}
}
}
class ReadWriteObject{
private int data;
public void read()
{
System.out.println(Thread.currentThread().getName()+"我正准备读呢");
try { Thread.sleep(new Random().nextInt(10000)); } catch (InterruptedException e) {}
System.out.println(Thread.currentThread().getName()+"读出来了:"+data);
}
public void write(int data)
{
System.out.println(Thread.currentThread().getName()+"我正准备写呢");
try { Thread.sleep(new Random().nextInt(10000)); } catch (InterruptedException e) {}
this.data=data;
System.out.println(Thread.currentThread().getName()+"写完了:"+data);
}
}

运行结果：0、2、4还没读完，1线程就开始写了

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下面让读写锁展示一下自己的独门绝技

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package xiaozhijingtian;
import java.util.Random;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class ReadWriteLockTest {
public static void main(String[] args) {
final ReadWriteObject object=new ReadWriteObject();
for(int i=0;i<3;i++)
{
new Thread(){
public void run() {
while(true)
object.read();
};
}.start();
new Thread(){
public void run() {
while(true)
object.write(new Random().nextInt(10));
};
}.start();
}
}
}
class ReadWriteObject{
private int data;
private ReadWriteLock readWriteLock=new ReentrantReadWriteLock();
public void read()
{
readWriteLock.readLock().lock();
System.out.println(Thread.currentThread().getName()+"我正准备读呢");
try { Thread.sleep(new Random().nextInt(10000)); } catch (InterruptedException e) {}
System.out.println(Thread.currentThread().getName()+"读出来了:"+data);
readWriteLock.readLock().unlock();
}
public void write(int data)
{
readWriteLock.writeLock().lock();
System.out.println(Thread.currentThread().getName()+"我正准备写呢");
try { Thread.sleep(new Random().nextInt(10000)); } catch (InterruptedException e) {}
this.data=data;
System.out.println(Thread.currentThread().getName()+"写完了:"+data);
readWriteLock.writeLock().unlock();
}
}

运行结果

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自己写一个缓存系统

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