当 mysql-connector-java-5 遇上 MySQL8，终究还是错付了 → 门当户对真的很重要！
开心一刻
今天，老婆给我发消息
老婆：老公，儿子从隔壁邻居家回来了
老婆：是先打还是先洗？
我：先洗吧，万一打错人了呢
老婆：先洗脸吧，没错就边打边洗
起因
在我们的固有认知中，
mysql-connector-java-5.x.x
连接的是
MySQL5
，而
mysql-connector-java-8.x.x
连接的是
MySQL8
如果用
mysql-connector-java-5.x.x
连接
MySQL8
，或者用
mysql-connector-java-8.x.x
连接
MySQL5
，会出问题
至于出什么问题，呃...，我没想过，也没试过，我相信你们也是一样的
但无意间，我尝试了下，确实有问题
一开始，我的一个
demo
是基于
MySQL 5.7.36
、
mysql-connector-java 5.1.26
、
MyBatis-Plus 3.1.0
示例代码：
play_it_safe
因为
MySQL 5.7.36
被我删了，而本机（
windows 10
）上正好有
MySQL 8.0.26
那就用
MySQL 8.0.26
来跑
demo
呗，只修改数据库连接的
url
、
username
和
password
然后就出现了一系列的异常
java.math.BigInteger cannot be cast to java.lang.Long
启动直接异常
java.sql.SQLException: java.lang.ClassCastException: java.math.BigInteger cannot be cast to java.lang.Long
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.buildCollationMapping(ConnectionImpl.java:1074) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3593) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2534) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2304) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) ~[mysql-connector-java-5.1.26.jar:na]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_91]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_91]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346) ~[mysql-connector-java-5.1.26.jar:na]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) [HikariCP-3.4.5.jar:na]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.buildSqlSessionFactory(MybatisSqlSessionFactoryBean.java:486) [mybatis-plus-extension-3.1.1.jar:3.1.1]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.afterPropertiesSet(MybatisSqlSessionFactoryBean.java:434) [mybatis-plus-extension-3.1.1.jar:3.1.1]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.getObject(MybatisSqlSessionFactoryBean.java:633) [mybatis-plus-extension-3.1.1.jar:3.1.1]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration.sqlSessionFactory(MybatisPlusAutoConfiguration.java:190) [mybatis-plus-boot-starter-3.1.1.jar:3.1.1]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$8802fc19.CGLIB$sqlSessionFactory$1(<generated>) [mybatis-plus-boot-starter-3.1.1.jar:3.1.1]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$8802fc19$$FastClassBySpringCGLIB$$f9d1deeb.invoke(<generated>) [mybatis-plus-boot-starter-3.1.1.jar:3.1.1]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) [spring-core-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) [spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$8802fc19.sqlSessionFactory(<generated>) [mybatis-plus-boot-starter-3.1.1.jar:3.1.1]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:650) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:635) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1336) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1176) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1307) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1227) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1509) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1404) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:878) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at com.qsl.PlayItSafeApplication.main(PlayItSafeApplication.java:16) ~[classes/:na]
Caused by: java.lang.ClassCastException: java.math.BigInteger cannot be cast to java.lang.Long
at com.mysql.jdbc.ConnectionImpl.buildCollationMapping(ConnectionImpl.java:1019) ~[mysql-connector-java-5.1.26.jar:na]
...64 common frames omitted
View Code
这确实出乎了我的意料，我认为的是：启动不会异常，运行中出现异常
既然异常来了，那就好好看看呗
怎么看？直接从异常堆栈中看，找到
Caused by
直接点击框住的，来到
mysql-connector-java 5.1.26
的源码
这个
for
循环遍历的是
sortedCollationMap
，
indexEntry
则表示遍历的当前元素
我问个问题：
java.math.BigInteger cannot be cast to java.lang.Long
异常是谁抛出来的，
getKey()
还是
intValue()
？
很简单，用排除法嘛
Long
是有
intValue()
方法的，只会
NPE
，不会
java.math.BigInteger cannot be cast to java.lang.Long
那就是
getKey()
抛出的异常呗，我们猜想下什么情况会抛出这个异常
indexEntry
声明的类型虽然是
Map.Entry<Long, String>
，但实际它的
key
不是
Long
类型，而是
BigInteger
类型？
再往上追溯一下，
sortedCollationMap
声明的类型是
TreeMap<Long, String>
，但实际存放元素的
key
是
BigInteger
类型？
此时你们对这个猜想肯定有疑问：这编译不会报错吗
直接
put
是会编译报错的，但是如果我变通下呢
编译没问题，但是执行会有如下异常
同样也是
int
collationIndex = entry.getKey().intValue();
抛出的异常
但两者原因是否一致，我们还需要对
play_it_safe
验证
如何验证，
debug
调试呗
断点不能打在
connectionimpl.java:1019
这一行，因为此时是遍历
sortedCollationMap
，而非往里面
put
元素
我们需要看，往
sortedCollationMap
里面
put
的
key
具体是什么类型，所以断点打在
1002
行
会走 if 分支
F7 跟进去
key
的类型就是
BigInteger
，证明我们的猜想是对的！
但是大家别高兴的太早，根因还没找到，我们得继续跟进
com.mysql.jdbc.ResultSetImpl#getObject(
int
)
重点看这个
switch
继续跟进，你会发现来到
BIGINT
分支
注意，重点来了
这段代码很简单，相信大家都能看到，但我还是分 3 块给大家说明下
1、
unsigned
表示无符号，然后再取反则表示有符号，也就是说如果数据库字段类型是
有符号
的
bigint
，则用
java.lang.Long
接收字段值并返回
2、如果数据库字段类型是
无符号
的
bigint
，则用
java.lang.String
来接收字段值，如果值为
null
则直接返回
null
3、如果数据库字段类型是
无符号
的
bigint
，并且字段值不是
null
，则用
java.math.BigInteger
来接收字段值并返回
此刻相信大家对异常的根因有点明白了，但又没有完全明白，为什么了？
因为没有弄清楚来龙去脉，我给大家捋一下：
1、程序启动过程（初始化）中，mysql-connector-java 5.1.26 会构建字段级字符集/字符序到java字符编码名称的映射
也就是会执行
com.mysql.jdbc.ConnectionImpl#buildCollationMapping
方法
2、
buildCollationMapping
方法中会执行 SQL
SHOW COLLATION
来获取
MySQL
的字符集和字符序
Id：字符序id
Charset：字符集名称
关于
MySQL
的字符集和字符序的更多信息，可查看
记一次字符串末尾空白丢失的排查 → MySQL 是会玩的！
3、从查询结果集中，逐行取第 3 列（
Id
）作为
key
，取第 2 列（
Charset
）作为
value
，
put
到
sortedCollationMap
中
对应代码就是：
Util.resultSetToMap(sortedCollationMap, results, 3, 2);
4、在取
Id
列值的时候，会根据数据库列类型，用不同的
java
类型来接收列值
MySQL 8.0.26
中，
COLLATIONS
表的
ID
列的类型是
bigint unsigned
那么用什么
java
类型来接收？往上面翻一翻，是不是用
java.math.BigInteger
来接收？
MySQL 5.7.36
中，
COLLATIONS
表的
ID
列的类型却是
bigint(11)
所以用
java.lang.Long
来接收
5、
for
循环遍历
sortedCollationMap
，完成数据库字段级字符集/字符序到java字符编码名称的映射
indexEntry.getKey()
在
MySQL 8.0.26
会抛出异常：
java.math.BigInteger cannot be cast to java.lang.Long
而在
MySQL 5.7.36
则正常，不抛出异常
至此，大家对根因是不是完全明白了？
说的简单点就是：
mysql-connector-java 5.1.26
配不上
MySQL 8
！
说的详细点就是：
mysql-connector-java 5.1.26
适配的是
COLLATIONS
的
bigint
类型的
ID
，而非
bigint unsigned
类型的
ID
说的抽象点就是：上岸第一剑 先斩意中人，
MySQL
从 5 上岸到了 8，
mysql-connector-java
如果不跟着上岸的话，会被第一个斩杀
Unknown system variable 'query_cache_size'
因为用的是
都说了能不动就别动，非要去调整，出生产事故了吧
中的
demo
：
play_it_safe
所以我顺手将
mysql-connector-java
调整到了
5.1.37
，
MySQL
还是
8.0.26
，结果启动出现了另一个异常
java.sql.SQLException: Unknown system variable 'query_cache_size'at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:959) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3870) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3806) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2470) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2617) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2546) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2504) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1370) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.loadServerVariables(ConnectionImpl.java:3861) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3289) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2298) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2084) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_91]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_91]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) [HikariCP-3.4.5.jar:na]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.buildSqlSessionFactory(MybatisSqlSessionFactoryBean.java:591) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.afterPropertiesSet(MybatisSqlSessionFactoryBean.java:422) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.getObject(MybatisSqlSessionFactoryBean.java:636) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration.sqlSessionFactory(MybatisPlusAutoConfiguration.java:172) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$eeb10e55.CGLIB$sqlSessionFactory$2(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$eeb10e55$$FastClassBySpringCGLIB$$de0ae008.invoke(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) [spring-core-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) [spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$eeb10e55.sqlSessionFactory(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:650) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:635) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1336) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1176) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1307) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1227) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1509) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1404) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:878) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at com.qsl.PlayItSafeApplication.main(PlayItSafeApplication.java:16) ~[classes/:na]
View Code
看到这个异常，不知道你们第一反应想到的是什么？
我第一反应想到的是
MySQL 8
取消了查询缓存，而
MySQL 5
是有查询缓存的
异常提示的已经很明显了，我们来验证下
MySQL 5.7.36
是有系统变量
query_cache_size
而
MySQL 8.0.26
是没有的
后面我又将
mysql-connector-java
升级到
5.1.42
，启动还是异常：
Unknown system variable 'query_cache_size'
Could not create connection to database server
因为需要用
MySQL 5.7.36
做对比，所以还是
Docker
快速安装了一个
MySQL 5.7.36
顺带也安装了
MySQL 8.0.26
（前面用的是
Win10
版，这个相当于是
Linux
版本）
然后我又鬼使神差的将连接调整到了
Linux
版的
MySQL 8.0.26
当
mysql-connector-java
是
5.1.42
时，启动异常是：
Unknown system variable 'query_cache_size'
当
mysql-connector-java
是
5.1.37
时，启动异常是：
Could not create connection to database server
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_91]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_91]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.Util.getInstance(Util.java:387) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:919) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:898) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:887) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:862) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2331) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2084) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_91]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_91]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) [HikariCP-3.4.5.jar:na]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.buildSqlSessionFactory(MybatisSqlSessionFactoryBean.java:591) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.afterPropertiesSet(MybatisSqlSessionFactoryBean.java:422) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.getObject(MybatisSqlSessionFactoryBean.java:636) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration.sqlSessionFactory(MybatisPlusAutoConfiguration.java:172) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$b0a04890.CGLIB$sqlSessionFactory$2(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$b0a04890$$FastClassBySpringCGLIB$$b0fb4ddc.invoke(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) [spring-core-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) [spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$b0a04890.sqlSessionFactory(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:650) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:635) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1336) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1176) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1307) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1227) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1509) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1404) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:878) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at com.qsl.PlayItSafeApplication.main(PlayItSafeApplication.java:16) ~[classes/:na]
Caused by: java.lang.NullPointerException:nullat com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3004) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1908) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1837) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1207) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2254) ~[mysql-connector-java-5.1.37.jar:5.1.37]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2285) ~[mysql-connector-java-5.1.37.jar:5.1.37]
...62 common frames omitted
View Code
关键异常堆栈是：
真正的异常其实是
NPE
，大家可以参考前面讲到的方法去分析
当
mysql-connector-java
是
5.1.26
时，启动异常也是：
Could not create connection to database server
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_91]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_91]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.Util.getInstance(Util.java:386) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1015) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2568) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2304) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) ~[mysql-connector-java-5.1.26.jar:na]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_91]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_91]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346) ~[mysql-connector-java-5.1.26.jar:na]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) [HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) [HikariCP-3.4.5.jar:na]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.buildSqlSessionFactory(MybatisSqlSessionFactoryBean.java:591) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.afterPropertiesSet(MybatisSqlSessionFactoryBean.java:422) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.getObject(MybatisSqlSessionFactoryBean.java:636) [mybatis-plus-extension-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration.sqlSessionFactory(MybatisPlusAutoConfiguration.java:172) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$8bb2ad81.CGLIB$sqlSessionFactory$1(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$8bb2ad81$$FastClassBySpringCGLIB$$fce7a55a.invoke(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) [spring-core-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) [spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$8bb2ad81.sqlSessionFactory(<generated>) [mybatis-plus-boot-starter-3.1.0.jar:3.1.0]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:650) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:635) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1336) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1176) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1307) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1227) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1509) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1404) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:878) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.10.RELEASE.jar:2.2.10.RELEASE]
at com.qsl.PlayItSafeApplication.main(PlayItSafeApplication.java:16) ~[classes/:na]
Caused by: java.lang.NullPointerException:nullat com.mysql.jdbc.ConnectionImpl.getServerCharacterEncoding(ConnectionImpl.java:3279) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1940) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1866) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1252) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2486) ~[mysql-connector-java-5.1.26.jar:na]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2519) ~[mysql-connector-java-5.1.26.jar:na]
...62 common frames omitted
View Code
关键异常堆栈是：
总结
MySQL
驱动版本和
MySQL
版本一定要门当户对，否则就会错付
要升就一起升，只升一边，就会出现升的一方看不上没升的那方：上岸第一剑 先斩意中人