Could not load driverClass ${jdbc.driver} java.lang.ClassNotFoundException: ${jdbc.driver}

异常提示：
4月 03, 2020 7:45:30 上午 com.mchange.v2.c3p0.DriverManagerDataSource ensureDriverLoaded
警告: Could not load driverClass ${jdbc.driver}
java.lang.ClassNotFoundException: ${jdbc.driver} at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581) at java.base/jdk.internal.loader.ClassLoaders$jdbc.driveratjava.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)atjava.base/jdk.internal.loader.ClassLoadersAppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:315)
…

从提示上看说是不能加载驱动类以及类找不到异常，我出问题的是这个JdbcConfig类

package config;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

import javax.sql.DataSource;

/**
 * 和spring连接数据库相关的配置类
 */
public class JdbcConfig {

    @Value("${jdbc.driver}")
    private String driver;

    @Value("${jdbc.url}")
    private String url;

    @Value("${jdbc.username}")
    private String username;

    @Value("${jdbc.password}")
    private String password;

    /**
     * 用于创建一个QueryRunner对象
     */
    @Bean(name="runner")
    @Scope("prototype")
    public QueryRunner createQueryRunner(DataSource dataSource){
        return new QueryRunner(dataSource);
    }

    /**
     * 创建数据源对象
     */
    @Bean(name="dataSource")
    public DataSource createDataSource(){
        ComboPooledDataSource ds = new ComboPooledDataSource();
        try{
            System.out.println(driver);
            ds.setDriverClass(driver);
            ds.setJdbcUrl(url);
            ds.setUser(username);
            ds.setPassword(password);
            return ds;
        }catch (Exception e){
            throw new RuntimeException(e);
        }
    }

}

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>4.2.6.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>javax.annotation</groupId>
      <artifactId>javax.annotation-api</artifactId>
      <version>1.3.2</version>
    </dependency>

    <dependency>
      <groupId>commons-dbutils</groupId>
      <artifactId>commons-dbutils</artifactId>
      <version>1.4</version>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.17</version>
    </dependency>

    <dependency>
      <groupId>c3p0</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.1.2</version>
    </dependency>

  </dependencies>

直接写入字符串是可以运行成功的

            ds.setDriverClass("com.mysql.jdbc.Driver");
            ds.setJdbcUrl("jdbc:mysql://localhost:3306/demo1?serverTimezone=UTC");
            ds.setUser("root");
            ds.setPassword("password");

也就是说注解没有给类中变量注入成功，将maven中引入的Spring依赖由4.2.6换成5.1.5就成功了

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.1.5.RELEASE</version>
    </dependency>

借鉴来源：
https://blog.csdn.net/weixin_43742184/article/details/99631772