多线程7Lock

Sychronized不需要显示的获取、释放锁，简单
Lock需要显示地获取锁和释放锁，繁琐但能让代码更灵活
使用Lock需要显示地获取和释放锁，Synchronized不需要显示释放锁，实现简单
Lock可以实现锁的公平性，非阻塞获取锁，非中断获取锁

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class Sequence {

    private int value;
    
//  需要显示地获取锁和释放锁，繁琐但能让代码更灵活
//  使用Lock需要显示地获取和释放锁，Synchronized不需要显示释放锁，实现简单
//  Lock可以实现锁的公平性，非阻塞获取锁，非中断获取锁
    Lock lock = new ReentrantLock();
    public int getNext(){
        
        lock.lock();
        int a= value++;
        lock.unlock();
        return a;
        
    }
    
    public static void main(String[] args) {
        Sequence s = new Sequence();
        
        new Thread(new Runnable() {
            
            @Override
            public void run() {
                // TODO Auto-generated method stub
                System.out.println(Thread.currentThread().getName()+" "+s.getNext());
            }
        }).start();
        
        new Thread(new Runnable() {
            
            @Override
            public void run() {
                // TODO Auto-generated method stub
                System.out.println(Thread.currentThread().getName()+" "+s.getNext());
            }
        }).start();
    }
}