當(dāng)我想使用 synchronized 關(guān)鍵字或鎖進(jìn)行更新時(shí)，它在 sum 變量為 int 時(shí)有效，但在它是 Integer 對(duì)象時(shí)無(wú)效。代碼看起來(lái)像這樣 -public class TestSynchronized { private Integer sum = new Integer(0); public static void main(String[] args) { TestSynchronized test = new TestSynchronized(); System.out.println("The sum is :" + test.sum); } public TestSynchronized() { ExecutorService executor = Executors.newFixedThreadPool(1000); for (int i = 0; i <=2000; i++) { executor.execute(new SumTask()); } executor.shutdown(); while(!executor.isTerminated()) { } } class SumTask implements Runnable { Lock lock = new ReentrantLock(); public void run() { lock.lock(); int value = sum.intValue() + 1; sum = new Integer(value); lock.unlock(); // Release the lock } }}
1 回答
四季花海
TA貢獻(xiàn)1811條經(jīng)驗(yàn) 獲得超5個(gè)贊
問(wèn)題是您已將locks每個(gè)SumTask對(duì)象分開(kāi)。這些對(duì)象應(yīng)該共享locks。
lock在TestSynchronized()方法中創(chuàng)建一次對(duì)象。這應(yīng)該由所有new SumTask(lock)對(duì)象共享。
所以你的SumTask班級(jí)看起來(lái)像：
class SumTask implements Runnable {
Lock lock;
public SumTask(Lock commonLock) {
this.lock = commonLock;
}
public void run() {
lock.lock();
int value = sum.intValue() + 1;
sum = new Integer(value);
lock.unlock(); // Release the lock
}
}
并且不要忘記commonLock在TestSynchronized()方法中創(chuàng)建一個(gè)對(duì)象：
Lock lock = new ReentrantLock();
executor.execute(new SumTask(commonLock));
添加回答
舉報(bào)
0/150
提交
取消