Could not create connection to database server. Attempted reconnect 3 times. Giving up.

• 报数据库连接错误

java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:906) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:831) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:149) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:218) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:143) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1515) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1578) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2466) [druid-1.1.9.jar:1.1.9]
Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���׼ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
	at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?]
	at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:?]
	at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?]
	at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) ~[?:?]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:481) ~[?:?]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2121) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2145) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:869) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	... 10 more
 2021-03-24 23:11:34.692 ERROR 7744 --- [eate-1149892111] c.a.d.p.DruidDataSource                  : create connection SQLException, url: jdbc:mysql://localhost:3306/db-mcms-open?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&allowMultiQueries=true&useSSL=true, errorCode 0, state 08001

java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:906) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:831) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:149) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:218) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:143) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1515) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1578) ~[druid-1.1.9.jar:1.1.9]
	at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2466) [druid-1.1.9.jar:1.1.9]
Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���׼ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
	at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?]
	at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:?]
	at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?]
	at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) ~[?:?]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:481) ~[?:?]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2121) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2145) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:869) ~[mysql-connector-java-8.0.18.jar:8.0.18]
	... 10 more

1. 错误
   create connection SQLException
   创建连接数据库发生了意外
   错误原因：
   Could not create connection to database server. Attempted reconnect 3 times. Giving up.
   无法创建到数据库服务器的连接。尝试重新连接3次。放弃。

2. 原因

---

1

***springboot 2.0（包括高版本的jdk）如果不配置这个会报时区错误；我这里指定的是亚洲上海的区时
3. 解决办法
指定区时
url中加入 &serverTimezone=UTC
（选择UTC会比中国早8个小时，如果在中国可以选择
Asia/Shanghai或者Asia/Hongkong ）

  url: jdbc:mysql://localhost:3306/db-mcms-open?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&allowMultiQueries=true&useSSL=true&serverTimezone=Asia/Shanghai

---

2

---

MySQL数据库未开启导致报错 ，启动MySQL数据库即解决
即解决
2021.3.21号错误

---

3

---

MySQL数据库版本和导入的jar包差异过大，由于每个人原因可能不一样，本人的mysql数据库为
8.0.21,但是导入的是5.1.47的jar包，导致报错，修改导入的依赖版本之后，还是报错
原因

driver-class-name: org.gjt.mm.mysql.Driver

应该将其改为

driver-class-name: com.mysql.cj.jdbc.Driver

问题即解决