03 2024 档案
摘要：https://javaguide.cn/database/sql/sql-questions-01.html 小总结 using()函数适用联表字段一致情况的join having能使用select别名筛选 SELECT order_num, COUNT(*) AS items FROM Orde
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摘要：Semaphore https://www.bilibili.com/video/BV1Ae411C7xr/ public class Semaphore implements java.io.Serializable 同Reetrantlock在Sync 继承AQS abstract static
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摘要：public class ThreadPoolExecutor extends AbstractExecutorService private final AtomicInteger ctl = new AtomicInteger(ctlOf(RUNNING, 0)); ctl int32位 高3位
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摘要：ThreadLocal set public void set(T value) { Thread t = Thread.currentThread(); ThreadLocalMap map = getMap(t); if (map != null) //map不为null,之前设置过情况 map
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