java - 解锁锁定同步块(synchronized block)的可靠方法

Question

系统偶尔会在同步块(synchronized block)上抛出严重错误，并且理论上应该有一个 try-catch 启动线程“解锁”过程，但这不会被触发。因此，我可以得出结论，这在系统内不被视为异常(exception)。有没有合理的方法来处理所述锁？

考虑 board.jsp 中的以下代码:

account = Account.get(accountID);
Object synch=account;

if(synch == null) {
    %>No account.<%
    return;
}
try {
    synchronized(synch) {
        ....
    }
} catch (Exception e) {
    ....
} finally {
    ....
}

示例转储

SEVERE: Scheduled tasks not running!
Apr 07, 2020 4:59:36 PM ExecLauncher:execLauncher run
SEVERE: ---------------------
Thread is: "http-bio-8080-exec-18" Id=122 BLOCKED on com.main.Account@5a0b8133 owned by "http-bio-8080-exec-7" Id=38
        at org.apache.jsp.realtime.board_jsp._jspService(board_jsp.java:192)
        -  blocked on com.main.Account@5a0b8133
        at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)

感谢您的浏览:)

Answer 1

您可以尝试一下，您将获得更多控制权来使用可重入锁显式锁定和解锁。

account = Account.get(accountID);
Object synch=account;
Lock lock = new ReentrantLock();


if(synch == null) {
    %>No account.<%
    return;
}
try {
lock.lock();
    /* Your actual code which you were executing in 
      the synchronized block */
} catch (Exception e) {
    ....
} finally {
    lock.unlock(); // this will work
}