本地数据库：

select version(); -- 查看数据库版本

5.0.18-nt

Caused by: com.mysql.cj.exceptions.UnableToConnectException: CLIENT_PLUGIN_AUTH is required
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_66]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_66]
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_66]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:422) ~[na:1.8.0_66]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.27.jar:8.0.27]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.27.jar:8.0.27]
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.connect(NativeAuthenticationProvider.java:152) ~[mysql-connector-java-8.0.27.jar:8.0.27]
	at com.mysql.cj.protocol.a.NativeProtocol.connect(NativeProtocol.java:1369) ~[mysql-connector-java-8.0.27.jar:8.0.27]
	at com.mysql.cj.NativeSession.connect(NativeSession.java:133) ~[mysql-connector-java-8.0.27.jar:8.0.27]
	at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:948) ~[mysql-connector-java-8.0.27.jar:8.0.27]
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:818) ~[mysql-connector-java-8.0.27.jar:8.0.27]
	... 88 common frames omitted

解决办法:

在pom.xml 中 配置低版本的mysql 驱动的jar包

<mysql.version>5.1.6</mysql.version>

 详情：pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.mw</groupId>
    <artifactId>multipiedb</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>multipiedb</name>
    <description>multipiedb project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <!-- spring boot版本过高报错  -->
        <mysql.version>5.1.6</mysql.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</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>2.2.0</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

</project>