Java多线程之Synchronized应用在static和非static方法上的区别

同步static方法：

public class Bank implements Runnable{

static int money = 2700;

//注意区别
public static synchronized void Withdraw() {
//public synchronized void Withdraw() {
for(int i=0; i<3;i++){
int temp = money;
temp = temp-300;
money = temp;
System.out.println(Thread.currentThread().getName()+" "+money);
}
}

public void run(){
Withdraw();
}

public static void main(String[] args) throws InterruptedException {
Bank b1 = new Bank();
Bank b2 = new Bank();
Bank b3 = new Bank();
Thread t1 = new Thread(b1,"b1");
Thread t2 = new Thread(b2,"b2");
Thread t3 = new Thread(b3,"b3");
t1.start();
t2.start();
t3.start();
t1.join();
t2.join();
t3.join();
System.out.println("The remaining money is "+money);
}

}结果为：
b1 2400

b1 2100

b1 1800

b2 1500

b2 1200

b2 900

b3 600

b3 300

b3 0

The remaining money is 0

同步非static方法：

public class Bank implements Runnable{

static int money = 2700;

//注意区别
//public static synchronized void Withdraw() {
public synchronized void Withdraw() {
for(int i=0; i<3;i++){
int temp = money;
temp = temp-300;
money = temp;
System.out.println(Thread.currentThread().getName()+" "+money);
}
}

public void run(){
Withdraw();
}

public static void main(String[] args) throws InterruptedException {
Bank b1 = new Bank();
Bank b2 = new Bank();
Bank b3 = new Bank();
Thread t1 = new Thread(b1,"b1");
Thread t2 = new Thread(b2,"b2");
Thread t3 = new Thread(b3,"b3");
t1.start();
t2.start();
t3.start();
t1.join();
t2.join();
t3.join();
System.out.println("The remaining money is "+money);
}

}
结果为：

b2 2100

b3 2100

b1 2100

b3 1500

b2 1800

b3 900

b1 1200

b2 600

b1 300

The remaining money is 300