Prefacio
Los bloqueos de lectura no son mutuamente excluyentes y se pueden obtener al mismo tiempo
import lombok.SneakyThrows;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class Demo07 {
public static void main(String[] args) {
Demo07Service service = new Demo07Service();
Demo07ThreadA t1 = new Demo07ThreadA(service);
Demo07ThreadA t2 = new Demo07ThreadA(service);
t1.setName("读线程01");
t2.setName("读线程02");
t1.start();
t2.start();
}
}
class Demo07Service{
private ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
public void read() throws InterruptedException {
lock.readLock().lock();
System.out.println(Thread.currentThread().getName()+" 获得读锁于:"+System.currentTimeMillis());
Thread.sleep(1000L);
System.out.println(Thread.currentThread().getName()+" 释放读锁于:"+System.currentTimeMillis());
lock.readLock().unlock();
}
public void write() throws InterruptedException {
lock.writeLock().lock();
System.out.println(Thread.currentThread().getName()+" 获得写锁于:"+System.currentTimeMillis());
Thread.sleep(1000L);
System.out.println(Thread.currentThread().getName()+" 释放写锁于:"+System.currentTimeMillis());
lock.writeLock().unlock();
}
}
class Demo07ThreadA extends Thread{
private Demo07Service service;
public Demo07ThreadA(Demo07Service service){
this.service = service;
}
@SneakyThrows
@Override
public void run() {
service.read();
}
}
class Demo07ThreadB extends Thread{
private Demo07Service service;
public Demo07ThreadB(Demo07Service service){
this.service = service;
}
@SneakyThrows
@Override
public void run() {
service.write();
}
}
resultado de la operación
Los bloqueos de escritura son mutuamente excluyentes y no se pueden obtener al mismo tiempo
t4.start();
}
}
class Demo07Service{
private ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
public void read() throws InterruptedException {
lock.readLock().lock();
System.out.println(Thread.currentThread().getName()+" 获得读锁于:"+System.currentTimeMillis());
Thread.sleep(1000L);
System.out.println(Thread.currentThread().getName()+" 释放读锁于:"+System.currentTimeMillis());
lock.readLock().unlock();
}
public void write() throws InterruptedException {
lock.writeLock().lock();
System.out.println(Thread.currentThread().getName()+" 获得写锁于:"+System.currentTimeMillis());
Thread.sleep(1000L);
System.out.println(Thread.currentThread().getName()+" 释放写锁于:"+System.currentTimeMillis());
lock.writeLock().unlock();
}
}
class Demo07ThreadA extends Thread{
private Demo07Service service;
public Demo07ThreadA(Demo07Service service){
this.service = service;
}
@SneakyThrows
@Override
public void run() {
service.read();
}
}
class Demo07ThreadB extends Thread{
private Demo07Service service;
public Demo07ThreadB(Demo07Service service){
this.service = service;
}
@SneakyThrows
@Override
public void run() {
service.write();
}
}
En conclusión
- Leer y escribir y escribir y leer son mutuamente excluyentes, siempre que haya una operación de escritura, son mutuamente excluyentes
- La lectura es compartida