Exception in thread "main" org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:83)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:376)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:431)
	at com.xyj.test.JdbcTemplateTest.main(JdbcTemplateTest.java:16)
Caused by: com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:172)
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
	at java.sql.DriverManager.getConnection(DriverManager.java:664)
	at java.sql.DriverManager.getConnection(DriverManager.java:208)
	at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriverManager(DriverManagerDataSource.java:155)
	at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriver(DriverManagerDataSource.java:146)
	at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnectionFromDriver(AbstractDriverBasedDataSource.java:205)
	at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnection(AbstractDriverBasedDataSource.java:169)
	at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:159)
	at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:117)
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
	... 3 more
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:103)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:149)
	at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:165)
	at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:355)
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.negotiateSSLConnection(NativeAuthenticationProvider.java:789)
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.proceedHandshakeWithPluggableAuthentication(NativeAuthenticationProvider.java:499)
	at com.mysql.cj.protocol.a.NativeAuthenticationProvider.connect(NativeAuthenticationProvider.java:217)
	at com.mysql.cj.protocol.a.NativeProtocol.connect(NativeProtocol.java:1411)
	at com.mysql.cj.NativeSession.connect(NativeSession.java:165)
	at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:982)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:852)
	... 15 more
Caused by: javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Path does not chain with any of the trust anchors
	at sun.security.ssl.Alert.createSSLException(Alert.java:131)
	at sun.security.ssl.TransportContext.fatal(TransportContext.java:370)
	at sun.security.ssl.TransportContext.fatal(TransportContext.java:313)
	at sun.security.ssl.TransportContext.fatal(TransportContext.java:308)
	at sun.security.ssl.CertificateMessage$T12CertificateConsumer.checkServerCerts(CertificateMessage.java:652)
	at sun.security.ssl.CertificateMessage$T12CertificateConsumer.onCertificate(CertificateMessage.java:471)
	at sun.security.ssl.CertificateMessage$T12CertificateConsumer.consume(CertificateMessage.java:367)
	at sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:376)
	at sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:479)
	at sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:457)
	at sun.security.ssl.TransportContext.dispatch(TransportContext.java:200)
	at sun.security.ssl.SSLTransport.decode(SSLTransport.java:154)
	at sun.security.ssl.SSLSocketImpl.decode(SSLSocketImpl.java:1290)
	at sun.security.ssl.SSLSocketImpl.readHandshakeRecord(SSLSocketImpl.java:1199)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:401)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:373)
	at com.mysql.cj.protocol.ExportControlled.performTlsHandshake(ExportControlled.java:213)
	at com.mysql.cj.protocol.StandardSocketFactory.performTlsHandshake(StandardSocketFactory.java:206)
	at com.mysql.cj.protocol.a.NativeSocketConnection.performTlsHandshake(NativeSocketConnection.java:99)
	at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:350)
	... 22 more
Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Path does not chain with any of the trust anchors
	at com.mysql.cj.protocol.ExportControlled$X509TrustManagerWrapper.checkServerTrusted(ExportControlled.java:280)
	at sun.security.ssl.AbstractTrustManagerWrapper.checkServerTrusted(SSLContextImpl.java:1255)
	at sun.security.ssl.CertificateMessage$T12CertificateConsumer.checkServerCerts(CertificateMessage.java:636)
	... 37 more
Caused by: java.security.cert.CertPathValidatorException: Path does not chain with any of the trust anchors
	at sun.security.provider.certpath.PKIXCertPathValidator.validate(PKIXCertPathValidator.java:158)
	at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(PKIXCertPathValidator.java:84)
	at java.security.cert.CertPathValidator.validate(CertPathValidator.java:292)
	at com.mysql.cj.protocol.ExportControlled$X509TrustManagerWrapper.checkServerTrusted(ExportControlled.java:273)
	... 39 more

Process finished with exit code 1

在pom文件种增加：

<dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.3.12</version>
    </dependency>