不可重入锁
public class MyLock implements Lock {
private boolean isLocked = false;
@Override
public synchronized void lock() {
while (isLocked){
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
isLocked = true;
}
@Override
public synchronized void unlock() {
isLocked = false;
notify();
}
其他的方法不用重写
}
可重入锁
public class MyLock implements Lock {
private boolean isLocked = false;
int lockCount = 0;
Thread lockBy = null;
@Override
public synchronized void lock() {
while (isLocked && lockBy != Thread.currentThread()){
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
isLocked = true;
lockBy = Thread.currentThread();
lockCount++;
}
@Override
public synchronized void unlock() {
if (lockBy == Thread.currentThread()){
lockCount--;
if (lockCount == 0){
isLocked = false;
notify();
}
}
}
区别
不可重入锁获取锁的条件:1,锁没被获取;2,是该线程的第一次获取。
而可重入锁获取锁的条件:1,锁没被获取;2,是否是当前线程获取的。
不可重入锁关心的是锁是否被一个线程获取过,直接释放锁。
可重入锁关心的是是否是当前线程获取的,当lockCount为0时释放。