我正在嘗試按照此處的教程mysql使用連接池連接到數據庫：apache dbcp2https://git-wip-us.apache.org/repos/asf?p=commons-dbcp.git;a=blob;f=doc/PoolingDataSourceExample.java;h=2a12c74898930b9623223db1597b8a8052a6f1df;hb=HEAD返回連接的我的數據庫連接類如下所示：public class DbConnection {private static interface Singleton {    final DbConnection INSTANCE = new DbConnection();}private final PoolingDataSource<PoolableConnection> dataSource;private DbConnection() {    // A ConnectionFactory that the pool will use to create Connections.    DriverManagerConnectionFactory connectionFactory = new DriverManagerConnectionFactory(url, user, pass);  //url,user,pass for db connnection    //implement the pooling functionality.    PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory, null);    GenericObjectPoolConfig config = new GenericObjectPoolConfig();    config.setMaxWaitMillis(500);    config.setMaxTotal(20);    config.setMaxIdle(5);    config.setMinIdle(5);    //PoolingDataSource expect an ObjectPool    ObjectPool<PoolableConnection> connectionPool = new GenericObjectPool<>(poolableConnectionFactory, config);    // Set the poolableConnectionFactory's pool property to the owning pool    poolableConnectionFactory.setPool(connectionPool);    this.dataSource = new PoolingDataSource<>(connectionPool);}public static Connection getCon() throws SQLException {    return Singleton.INSTANCE.dataSource.getConnection();}} 我正在使用 apache jmeter 來測試連接并從我的 mysql 數據庫返回一些東西。我創建了 100 個用戶，啟動時間（以秒為單位）為 2 秒。我創建了一個Http request，當我試圖在其中查看我的響應時，view results tree我成功地獲得了前 20 個請求的響應。來自（21 到 100）的后續請求有空白響應。我經歷了許多涉及的問題：java.sql.SQLException：無法獲取連接，池錯誤等待空閑對象超時