在Eclipse中启动项目时，报如下错误：

at java.sql.SQLException: Unable to load authentication plugin 'caching_sha2_password'. 
at at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:868) 
at at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:864) 
at at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1746) 
at at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1226) 
at at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2191) 
at at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2222) 
at at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2017) 
at at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:779) 
at at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:47) 
at at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
at at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) 
at at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) 
at at java.lang.reflect.Constructor.newInstance(Unknown Source) 
at at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) 
at at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:389) 
at at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330) 
at at java.sql.DriverManager.getConnection(Unknown Source) 
at at java.sql.DriverManager.getConnection(Unknown Source) 
at at ch.qos.logback.core.db.DriverManagerConnectionSource.getConnection(DriverManagerConnectionSource.java:54) 
at at ch.qos.logback.core.db.ConnectionSourceBase.discoverConnectionProperties(ConnectionSourceBase.java:46) 
at at ch.qos.logback.core.db.DriverManagerConnectionSource.start(DriverManagerConnectionSource.java:38) 
at at ch.qos.logback.core.joran.action.NestedComplexPropertyIA.end(NestedComplexPropertyIA.java:161) 
at at ch.qos.logback.core.joran.spi.Interpreter.callEndAction(Interpreter.java:309) 
at at ch.qos.logback.core.joran.spi.Interpreter.endElement(Interpreter.java:193) 
at at ch.qos.logback.core.joran.spi.Interpreter.endElement(Interpreter.java:179) 
at at ch.qos.logback.core.joran.spi.EventPlayer.play(EventPlayer.java:62) 
at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:165) 
at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:152) 
at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:110) 
at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:53) 
at at ch.qos.logback.classic.util.ContextInitializer.configureByResource(ContextInitializer.java:75) 
at at ch.qos.logback.classic.util.ContextInitializer.autoConfig(ContextInitializer.java:150) 
at at org.slf4j.impl.StaticLoggerBinder.init(StaticLoggerBinder.java:84) 
at at org.slf4j.impl.StaticLoggerBinder.(StaticLoggerBinder.java:55) 
at at org.slf4j.LoggerFactory.bind(LoggerFactory.java:150) 
at at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:124) 
at at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:412) 
at at ch.qos.logback.classic.util.StatusViaSLF4JLoggerFactory.addStatus(StatusViaSLF4JLoggerFactory.java:32) 
at at ch.qos.logback.classic.util.StatusViaSLF4JLoggerFactory.addInfo(StatusViaSLF4JLoggerFactory.java:20) 
at at ch.qos.logback.classic.servlet.LogbackServletContainerInitializer.onStartup(LogbackServletContainerInitializer.java:32) 
at at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5245) 
at at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) 
at at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1421) 
at at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1411) 
at at java.util.concurrent.FutureTask.run(Unknown Source) 
at at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) 
at at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 
at at java.lang.Thread.run(Unknown Source)。

问题原因：

Mysql8.0.11版本之后，不默认使用mysql5.7及以前版本那种方式，即设置用户密码时默认的验证方式为caching_sha2_password，升级mysql8.0.11后原来的程序不能连接mysql，可以在mysql command line client客户端用下面的命令设置成mysql5.7及以前版本的密码验证方式，同时MYSQL8.0.11下修改密码的方式与原先也不大一样，之前部分修改密码的命令在mysql8.0.11下不能使用。

1、尝试修改MySQL密码解决问题

Mysql8.0.11版本之后修改密码方法

ALTER USER 'cjavapy'@'localhost' IDENTIFIED WITH mysql_native_password BY 'pass258';

2、更新mysql-connector解决问题

将mysql-connector改成如下版本：

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
    <version>8.0.13</version>
</dependency>

参考文档：https://dev.mysql.com/doc/refman/8.0/en/caching-sha2-pluggable-authentication.html