9-Druid销毁线程

9.1 简介

在前面的博文中我们介绍了创建Druid连接的线程的逻辑《6-DruidDataSource物理连接创建线程createAndStartCreatorThread》 ，这里来看下销毁连接的逻辑。
这个代码调用逻辑是来源于前面说的DruidDataSource的连接对象获取时的初始化方法init
调用代码如下：

 createAndStartDestroyThread();
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9.2 创建销毁线程的具体逻辑

直接来看DruidDataSource类型的createAndStartDestroyThread代码如下所示：

  protected void createAndStartDestroyThread() {
       //创建销毁任务
        destroyTask = new DestroyTask();

		//这里我们没有配置销毁定时器
        if (destroyScheduler != null) {
            long period = timeBetweenEvictionRunsMillis;
            if (period <= 0) {
                period = 1000;
            }
            destroySchedulerFuture = destroyScheduler.scheduleAtFixedRate(destroyTask, period, period,
                    TimeUnit.MILLISECONDS);
            initedLatch.countDown();
            return;
        }

        String threadName = "Druid-ConnectionPool-Destroy-" + System.identityHashCode(this);
        //创建与启动销毁线程
        destroyConnectionThread = new DestroyConnectionThread(threadName);
        destroyConnectionThread.start();
    }

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9.3 销毁线程代码

这里直接来看代码了

public class DestroyConnectionThread extends Thread {
        public DestroyConnectionThread(String name) {
            super(name);
            this.setDaemon(true);
        }

        public void run() {
            initedLatch.countDown();

            for (; ; ) {
                // 从前面开始删除
                try {
                    if (closed || closing) {
                        break;
                    }

                    if (timeBetweenEvictionRunsMillis > 0) {
                        Thread.sleep(timeBetweenEvictionRunsMillis);
                    } else {
                        Thread.sleep(1000); //
                    }

                    if (Thread.interrupted()) {
                        break;
                    }

                    destroyTask.run();
                } catch (InterruptedException e) {
                    break;
                }
            }
        }

    }
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9.4 销毁任务代码

看下销毁任务的代码：

 public class DestroyTask implements Runnable {
        public DestroyTask() {
        }

        @Override
        public void run() {
            shrink(true, keepAlive);

            if (isRemoveAbandoned()) {
                removeAbandoned();
            }
        }

    }
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shrink

移除空闲连接removeAbandoned