我们何时可以在 Java 中使用 Synchronized 块?
javaobject oriented programmingprogramming更新于 2024/7/25 21:57:00
Synchronized 块是一段代码，可用于对方法的任何特定资源执行同步。Synchronized 块用于锁定任何共享资源的对象，同步块的范围小于同步方法。
语法
synchronized(object) {
// 代码块
}
此处，对象是对正在同步的对象的引用。同步块确保仅在当前线程成功进入对象监视器后才会调用对象成员的方法。
示例
class TicketCounter {
int availableSeats = 2;
void bookTicket(String name, int numberOfSeats) {
if((availableSeats >= numberOfSeats) && (numberOfSeats > 0)) {
System.out.println(name+" : "+ numberOfSeats + " Seats Booking Success");
availableSeats -= numberOfSeats;
} else {
System.out.println(name +" : Seats Not Available");
}
}
}
class TicketBookingThread extends Thread {
TicketCounter tc;
String name;
int seats;
TicketBookingThread(TicketCounter tc, String name, int seats) {
this.tc = tc;
this.name = name;
this.seats = seats;
}
public void run() {
synchronized(tc) { // synchronized block tc.bookTicket(name, seats);
}
}
}
public class SynchronizedBlockTest {
public static void main(String[] args) {
TicketCounter tc = new TicketCounter();
TicketBookingThread t1 = new TicketBookingThread(tc, "Adithya", 2);
TicketBookingThread t2 = new TicketBookingThread(tc, "Jai", 2);
t1.start();
t2.start();
}
}
输出
Adithya : 2 Seats Booking Success Jai : Seats Not Available
