老师，用IDEA手工创建c3p0连接池的方法可以获得连接，用配置文件就会抛异常 这是什么问题？

数据库:8.0+

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>

  <default-config>
    <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
    <!-- &=>&amp; &用 &amp; 代替-->
   <property name="jdbcUrl">jdbc:mysql:///jdbctest?useSSL=false&amp;serverTimezone=Hongkong&amp;useUnicode=true&amp;characterEncoding=utf-8</property>
   <property name="user">root</property>
   <property name="password">1234</property>
   <property name="initialPoolSize">5</property>
   <property name="maxPoolSize">20</property>
  </default-config>
  
</c3p0-config>

package com.gavin.utils;

import com.mchange.v2.c3p0.ComboPooledDataSource;


import java.sql.*;

public class JDBC_c3p0 {
    private static final ComboPooledDataSource dataSource = new ComboPooledDataSource();

    /**
     * 获得连接的方法:
     * @throws SQLException
     */
    public static Connection getConnection() throws Exception{
        Connection conn = dataSource.getConnection();
        return conn;
    }

    public static void release(ResultSet rs,Statement stmt,Connection conn){
        if(rs!= null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            rs = null;
        }
        if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            stmt = null;
        }
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            conn = null;
        }
    }
}

这两个是什么意思?

java.sql.SQLException: No suitable driver

java.sql.SQLException: Connections could not be acquired from the underlying database!