1.写一个体验redis缓存的demo，不能连接数据库。
导入其他人的项目可以，连接自己的数据库，可以连接成功。确定数据库连接信息没有写错。参考网上,修改mysql-connector-java的版本也没有用。
系统环境：java-1.8; mysql-5.1.62; IDEA 2019-1.4;SpringBoot 2.2.2;
2.pom文件：

<?xml version="1.0" encoding="UTF-8"?>
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0

org.springframework.boot
spring-boot-starter-parent
2.2.2.RELEASE


com.example
cache
0.0.1-SNAPSHOT
cache
Demo project for Spring Boot

<properties>
<java.version>1.8</java.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.1</version>
</dependency>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.34</version>
<scope>runtime</scope>
</dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>