线程加锁this详解

1：用this和类名.class却别对象时加锁的不同

用this

多线程调用同方法时 要调用的同一个第一对象的方法 不然打达不到线程加锁 因为他调用的是不同对象的锁

A a = new A();

Thread th1 = new Thread(a);

th1.start();

Thread th2 = new Thread(a);

th2.start();

Thread th3 = new Thread(a);

th3.start();

Thread th4 = new Thread(a);

th4.start();

public void run() {

while(flag){

synchronized (this) {

if(count<TATOL){

salticket();

}else{

flag = false;

}

}

try {

Thread.sleep(100);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

用类名.class

不管实例化多少个对象 是对类对象进行加锁（反射）所以可以实例化多个对象 但仍可实现对同方法的加锁

Thread th1 = new Thread( new A());

th1.start();

Thread th2 = new Thread( new A());

th2.start();

Thread th3 = new Thread( new A());

th3.start();

public void run() {

while(flag){

synchronized (A.class) {

if(count<TATOL){

salticket();

}else{

flag = false;

}

}

try {

Thread.sleep(100);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}