错误解决记录(持续更新)

本文记录了在IDEA中遇到的数据库连接问题及单元测试时的数据库插入错误。解决方法包括在数据库连接字符串中添加`allowPublicKeyRetrieval=true`以及确保jar包版本与数据库版本一致,例如将5.1.37升级到8.0版本以匹配MySQL 8.0数据库。

注意事项

1、版本一定要匹配

2、jar包建在WEB-INF
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错误记录


错误一:在IDEA连接不了数据库

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最简单的解决方法是在连接后面添加 allowPublicKeyRetrieval=true

-------------------------------------------------------------------------------------------

错误二:当我使用单元测试检查我的数据库插入方法时出现的错误

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	二月 23, 2021 5:57:19 下午 com.alibaba.druid.pool.DruidDataSource error
严重: {dataSource-1} init error
java.sql.SQLException: com.mysql.cj.jdbc.Driver
	at com.alibaba.druid.util.JdbcUtils.createDriver(JdbcUtils.java:625)
	at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:897)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1376)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1372)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:109)
	at com.dyx.util.DruidUtil.getConnection(DruidUtil.java:31)
	at com.dyx.dao.impl.UserDaoImpl.addUser(UserDaoImpl.java:12)
	at com.dyx.test.DBTest.TestAddUser(DBTest.java:17)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at com.alibaba.druid.util.JdbcUtils.createDriver(JdbcUtils.java:623)
	... 28 more

java.sql.SQLException: com.mysql.cj.jdbc.Driver
	at com.alibaba.druid.util.JdbcUtils.createDriver(JdbcUtils.java:625)
	at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:897)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1376)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1372)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:109)
	at com.dyx.util.DruidUtil.getConnection(DruidUtil.java:31)
	at com.dyx.dao.impl.UserDaoImpl.addUser(UserDaoImpl.java:12)
	at com.dyx.test.DBTest.TestAddUser(DBTest.java:17)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
false
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at com.alibaba.druid.util.JdbcUtils.createDriver(JdbcUtils.java:623)
	... 28 more

Process finished with exit code 0

我列举一下以上发生的错误

java.sql.SQLException: com.mysql.cj.jdbc.Driver

Caused by: java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver

java.sql.SQLException: com.mysql.cj.jdbc.Driver

Caused by: java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver

我们发现com.mysql.cj.jdbc.Driver都是mysql的jar包问题,后来我回想着我导入的jar是5.1.37版本,与我的mysql数据库的版本(我的是8.0)不匹配。

我把8.0版本的jar包导入后解决了问题

注意:写的方法的时候没有检查数据库的数据是否重复,所以使用同一查询语句的时候会报一个重复不能使用


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