Problem description
The SPringBoot project has been discontinued using MYSQL 5.7.43. The Java JDBC driver dependency selection is
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
The driver parameter configuration is as follows:
spring:
datasource:
username: root
password: root
url: jdbc:mysql://127.0.0.1:3306/data_backend?autoReconnect=true & amp;useUnicode=true & amp;characterEncoding=utf8 & amp;serverTimezone=GMT+8
driver-class-name: com.mysql.jdbc.Driver
When using the backend interface testing tool to test whether the backend interface is working properly, the error is as follows:
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_381] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_381] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_381] at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_381] at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.Util.getInstance(Util.java:408) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:919) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:898) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:887) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:861) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2105) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2030) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:778) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) ~[mysql-connector-java-5.1.47.jar:5.1.47] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_381] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_381] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_381] at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_381] at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330) ~[mysql-connector-java-5.1.47.jar:5.1.47] at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:364) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:476) [HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:561) [HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) [HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) [HikariCP-4.0.3.jar:na] at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:159) [spring-jdbc-5.3.22.jar:5.3.22] at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:117) [spring-jdbc-5.3.22.jar:5.3.22] at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80) [spring-jdbc-5.3.22.jar:5.3.22] at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:80) [mybatis-spring-2.0.7.jar:2.0.7] ................................................................. .................................................... ................................................................. .................................................... ................................................................. .................................................... ................................................................. .................................................... ................................................................. .................................................... ................................................................. .................................................... Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
Solution
The driver version of the Mysql database is incorrect.
Take a look at the version correspondence between connector/J and MYSQL:
It seems that the 5.1 driver also supports the 5.7 MYSQL database, but it just cannot be used. The official recommendation is to use or upgrade to the driver version 8.0. Try changing to the 8.0 database driver and changing the yml configuration file database driver information.
Change the version of mysql-Connector-java to 8.0.x. That is, replace the dependencies of 5.1.47 with the following dependencies:
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.19</version>
</dependency>
And configure the database driver in application.yml as com.mysql.cj.jdbc.Driver, as follows:
spring:
datasource:
username: root
password: root
url: jdbc:mysql://127.0.0.1:3306/data_backend?autoReconnect=true & amp;useUnicode=true & amp;characterEncoding=utf8 & amp;serverTimezone=GMT+8
driver-class-name: com.mysql.cj.jdbc.Driver
Restart the project and the backend interface can successfully access the database.