...jdbc4.MySQLNonTransientConnectionException: Client does not support authentication protocol

错误信息如下：

十月 31, 2019 3:34:30 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org[email protected]685f4c2e: startup date [Thu Oct 31 15:34:30 CST 2019]; root of context hierarchy
十月 31, 2019 3:34:30 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [jdbc_application.xml]
十月 31, 2019 3:34:31 下午 com.mchange.v2.log.MLog <clinit>
信息: MLog clients using java 1.4+ standard logging.
十月 31, 2019 3:34:31 下午 com.mchange.v2.c3p0.C3P0Registry banner
信息: Initializing c3p0-0.9.1.2 [built 21-May-2007 15:04:56; debug? true; trace: 10]
十月 31, 2019 3:34:31 下午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager
信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 2tgw9ta693051l6ltn3e|1e88b3c, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 2tgw9ta693051l6ltn3e|1e88b3c, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql://127.0.0.1:3306/test_db?serverTimezone=UTC, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]
十月 31, 2019 3:35:01 下午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run
警告: [email protected]c4 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Client does not support authentication protocol requested by server; consider upgrading MySQL client
    at sun.reflect.GeneratedConstructorAccessor9.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    ........

MYSQL服务器版本：MYSQL8.0.16

JDBC驱动：mysql-connector-java-5.1.7-bin.jar

解决方案：

JDBC驱动更换成：mysql-connector-java-8.0.16.jar

再次执行数据库连接操作如下：