什么时候可以在Java中使用同步块？
甲同步 块是一块代码，可以被用于在该方法的任何特定的资源执行同步。甲同步块用于锁定用于任何共享资源对象和同步块的范围是比小同步方法。
语法
synchronized(object) {
//代码块
}在此，对象是对要同步的对象 的引用。同步块可确保仅在当前线程成功进入对象的监视器之后，才对作为对象成员的方法进行调用。
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();
}
}输出结果
Adithya : 2 Seats Booking Success Jai : Seats Not Available