【Java】java 并发访问函数返回值问题?

Z时代
2024-01-10
分类：技术分享

在spring 容器环境下，通过synchronized(this)锁来执行耗时逻辑,这样能保证程序可用吗？
我测试下来如果没有返回值是能保证顺序, 有返回值就有问题.
:加synchronized 的原因是可能会并发去访问lockUserVouchers修改数据状态，修改成功或失败返回状态

@Test
public void testLock() throws InterruptedException {
CountDownLatch latch = new CountDownLatch(3);
for (int i = 1; i <= 3; i++) {
new Thread(new RunnerLock(userVouchersService, latch)).start();
}
latch.await();
}
public class RunnerLock implements Runnable {
UserVouchersService userVouchersService;
CountDownLatch countDownLatch;
public RunnerLock(UserVouchersService userVouchersService, CountDownLatch     countDownLatch) {
this.userVouchersService = userVouchersService;
this.countDownLatch = countDownLatch;
}
@Override
public void run() {
CsAuctionUserVouchers csAuctionUserVouchers = new CsAuctionUserVouchers();
csAuctionUserVouchers.setId(ThreadLocalRandom.current().nextLong(0, 9999));
long l = userVouchersService.lockUserVouchers(csAuctionUserVouchers);
log.info("---------------返回值 --- {}---------------------------------", l);
countDownLatch.countDown();
}
}
@Transactional(rollbackFor = Exception.class)
public long lockUserVouchers(CsAuctionUserVouchers csAuctionUserVouchers) {
synchronized (this) {
log.info("-------------------test开始----------------------");
try {
Thread.sleep(1000);
//修改数据状态，修改成功或失败返回状态
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("------------------ --test结束----------------------");
return csAuctionUserVouchers.getId();
}
}