druidDatasource，看看druid 连接池部分的源码-创建，使用，销毁。

[转]https://blog.csdn.net/qq_41376740/article/details/81869261

销毁线程

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

    public void run() {
        DruidDataSource.this.shrink(true, DruidDataSource.this.keepAlive);
        if (DruidDataSource.this.isRemoveAbandoned()) {
            DruidDataSource.this.removeAbandoned();
        }

    }
}
           

shrink的关键就在这，其主要功能是收缩就是空闲的太多了要进行回收了。

if (evictCount > 0) {
    for(checkCount = 0; checkCount < evictCount; ++checkCount) {
        holer = this.evictConnections[checkCount];
        connection = holer.getConnection();
        JdbcUtils.close(connection);
        destroyCountUpdater.incrementAndGet(this);
    }

    Arrays.fill(this.evictConnections, (Object)null);
}
           

if(keepAliveCount > 0) {
            this.getDataSourceStat().addKeepAliveCheckCount((long)keepAliveCount);

            for(checkCount = keepAliveCount - 1; checkCount >= 0; --checkCount) {
                holer = this.keepAliveConnections[checkCount];
                connection = holer.getConnection();
                holer.incrementKeepAliveCheckCount();
                boolean validate = false;

                try {
                    this.validateConnection(connection);
                    validate = true;
                } catch (Throwable var17) {
                    if(LOG.isDebugEnabled()) {
                        LOG.debug("keepAliveErr", var17);
                    }
                }

                if(validate) {
                    holer.lastActiveTimeMillis = System.currentTimeMillis();
                    this.put(holer);
                } else {
                    JdbcUtils.close(connection);
                }
            }

            Arrays.fill(this.keepAliveConnections, (Object)null);
        }