[TD-2597]<fix>: fix Druid and HikariCP configurations

tests/examples/JDBC/connectionPools/src/main/java/com/taosdata/demo/pool/DruidPoolBuilder.java

@@ -10,20 +10,18 @@ public class DruidPoolBuilder {
         final String url = "jdbc:TAOS://" + host + ":6030";
 
         DruidDataSource dataSource = new DruidDataSource();
+        // jdbc properties
         dataSource.setUrl(url);
         dataSource.setDriverClassName("com.taosdata.jdbc.TSDBDriver");
         dataSource.setUsername("root");
         dataSource.setPassword("taosdata");
 
-        //初始连接数，默认0
-        dataSource.setInitialSize(poolSize);
-        //最大连接数，默认8
-        dataSource.setMaxActive(poolSize);
-        //最小闲置数
-        dataSource.setMinIdle(poolSize);
-        //获取连接的最大等待时间，单位毫秒
-        dataSource.setMaxWait(2000);
-
+        // pool configurations
+        dataSource.setInitialSize(poolSize);//初始连接数，默认0
+        dataSource.setMinIdle(poolSize);//最小闲置数
+        dataSource.setMaxActive(poolSize);//最大连接数，默认8
+        dataSource.setMaxWait(30000);//获取连接的最大等待时间，单位毫秒
+        dataSource.setValidationQuery("select server_status()");
         return dataSource;
     }
 

tests/examples/JDBC/connectionPools/src/main/java/com/taosdata/demo/pool/HikariCpBuilder.java

@@ -9,13 +9,18 @@ public class HikariCpBuilder {
 
     public static DataSource getDataSource(String host, int poolSize) {
         HikariConfig config = new HikariConfig();
+        // jdbc properties
         config.setDriverClassName("com.taosdata.jdbc.TSDBDriver");
         config.setJdbcUrl("jdbc:TAOS://" + host + ":6030");
         config.setUsername("root");
         config.setPassword("taosdata");
+        // pool configurations
+        config.setMinimumIdle(3);           //minimum number of idle connection
+        config.setMaximumPoolSize(10);      //maximum number of connection in the pool
+        config.setConnectionTimeout(30000); //maximum wait milliseconds for get connection from pool
+        config.setIdleTimeout(0);       // max idle time for recycle idle connection
+        config.setConnectionTestQuery("select server_status()"); //validation query
 
-        config.setMaximumPoolSize(poolSize);
-        config.setMinimumIdle(poolSize);
         HikariDataSource ds = new HikariDataSource(config);
         return ds;
     }