2020-08-20 16:06:29.153 [localhost-startStop-1] ERROR com.zaxxer.hikari.pool.HikariPool - HikariCP - Exception during pool initialization. com.mysql.jdbc.exceptions.jdbc4.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 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.jdbc.Util.handleNewInstance(Util.java:425)         at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)         at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:342)         at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2197)         at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2230)         at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2025)         at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:778)         at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)         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.jdbc.Util.handleNewInstance(Util.java:425)         at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)         at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)         at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:117)         at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:123)         at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:365)         at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:194)

看了您的报错信息  您是数据库有问题啊   都是jdbc的报错

回复第2楼我Navicat使用数据库正常啊，但是启动部署就报这个错

数据库是本机上的嘛？

回复第4楼是本机的数据库
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/jeecms?useUnicode=true&characterEncoding=UTF-8&useSSL=false
#spring.datasource.url=jdbc:mysql://localhost:3308/jeecmsx1.3?useUnicode=true&characterEncoding=UTF-8&useSSL=false
spring.datasource.username=root
#spring.datasource.password=password
spring.datasource.password=admin

那您看下您的这个报错信息
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

回复第6楼 我换了个别的5.7mysql也是这个报错，差这个报错让更改最大连接数，改完了还是报错

他这个错误只是提示您
Communications link failure
通信链路故障
只是链接数据库失败啊