REPORT-67030 fix: mysql数据连接无法正常连接

fine-druid/src/main/java/com/fr/third/alibaba/druid/util/MySqlUtils.java

@@ -386,16 +386,15 @@ public class MySqlUtils {
 
     public static long getLastPacketReceivedTimeMs(Connection conn) throws SQLException {
         if (!class_connectionImpl_Error) {
-            if (conn == null) {
-                return -1;
-            }
             try {
-                //REPORT-66916 这里之前获取到的是lib下的mysql5实现，而不是自定义mysql8驱动的实现
-                String className = conn.getClass().getName();
-                class_connectionImpl = Utils.loadClass(className);
-                if (className.equals("com.mysql.cj.MysqlConnection")) {
+                mysqlJdbcVersion6 = false;
+                class_connectionImpl = Utils.loadClass("com.mysql.jdbc.MySQLConnection");
+                if (class_connectionImpl == null || class_connectionImpl.getClassLoader() != conn.getClass().getClassLoader()) {
+                    class_connectionImpl = Utils.loadClass("com.mysql.cj.MysqlConnection");
+                    if (class_connectionImpl != null) {
                         mysqlJdbcVersion6 = true;
                     }
+                }
             } catch (Throwable error) {
                 class_connectionImpl_Error = true;
             }
@@ -412,7 +411,7 @@ public class MySqlUtils {
                 return -1;
             }
 
-            if (getIdleFor == null && !getIdleForError) {
+            if (!getIdleForError) {
                 try {
                     getIdleFor = classJdbc.getMethod("getIdleFor");
                     getIdleFor.setAccessible(true);