连接mysql时发生Grails错误

我在连接mysql时遇到以下错误

我已将mysql-connector-java-5.1.22-bin.jar复制到应用程序中的lib文件夹中

| Error 2012-11-26 16:14:16,981 [localhost-startStop-1] ERROR context.GrailsContextLoader  - Error executing bootstraps: Error creating bean with name 'transactionManagerPostProcessor': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Cannot resolve reference to bean 'hibernateProperties' while setting bean property 'hibernateProperties'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'hibernateProperties': Cannot resolve reference to bean 'dialectDetector' while setting bean property 'properties' with key [hibernate.dialect]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dialectDetector': Invocation of init method failed; nested exception is org.springframework.jdbc.support.MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
Message: Error creating bean with name 'transactionManagerPostProcessor': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Cannot resolve reference to bean 'hibernateProperties' while setting bean property 'hibernateProperties'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'hibernateProperties': Cannot resolve reference to bean 'dialectDetector' while setting bean property 'properties' with key [hibernate.dialect]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dialectDetector': Invocation of init method failed; nested exception is org.springframework.jdbc.support.MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
    Line | Method
->>  334 | innerRun  in java.util.concurrent.FutureTask$Sync
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    166 | run       in java.util.concurrent.FutureTask
|   1110 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    603 | run       in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . in java.lang.Thread

Caused by BeanCreationException: Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Cannot resolve reference to bean 'hibernateProperties' while setting bean property 'hibernateProperties'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'hibernateProperties': Cannot resolve reference to bean 'dialectDetector' while setting bean property 'properties' with key [hibernate.dialect]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dialectDetector': Invocation of init method failed; nested exception is org.springframework.jdbc.support.MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
->>  334 | innerRun  in java.util.concurrent.FutureTask$Sync
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    166 | run       in java.util.concurrent.FutureTask
|   1110 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    603 | run       in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . in java.lang.Thread

Caused by BeanCreationException: Error creating bean with name 'sessionFactory': Cannot resolve reference to bean 'hibernateProperties' while setting bean property 'hibernateProperties'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'hibernateProperties': Cannot resolve reference to bean 'dialectDetector' while setting bean property 'properties' with key [hibernate.dialect]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dialectDetector': Invocation of init method failed; nested exception is org.springframework.jdbc.support.MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
->>  334 | innerRun  in java.util.concurrent.FutureTask$Sync
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    166 | run       in java.util.concurrent.FutureTask
|   1110 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    603 | run       in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . in java.lang.Thread

Caused by BeanCreationException: Error creating bean with name 'hibernateProperties': Cannot resolve reference to bean 'dialectDetector' while setting bean property 'properties' with key [hibernate.dialect]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dialectDetector': Invocation of init method failed; nested exception is org.springframework.jdbc.support.MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
->>  334 | innerRun  in java.util.concurrent.FutureTask$Sync
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    166 | run       in java.util.concurrent.FutureTask
|   1110 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    603 | run       in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . in java.lang.Thread

Caused by BeanCreationException: Error creating bean with name 'dialectDetector': Invocation of init method failed; nested exception is org.springframework.jdbc.support.MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
->>  334 | innerRun  in java.util.concurrent.FutureTask$Sync
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    166 | run       in java.util.concurrent.FutureTask
|   1110 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    603 | run       in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . in java.lang.Thread

Caused by MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
->>  334 | innerRun  in java.util.concurrent.FutureTask$Sync
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    166 | run       in java.util.concurrent.FutureTask
|   1110 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    603 | run       in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . in java.lang.Thread

Caused by SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
->> 1429 | createConnectionFactory in org.apache.commons.dbcp.BasicDataSource
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|   1371 | createDataSource in     ''
|   1044 | getConnection in     ''
|    334 | innerRun  in java.util.concurrent.FutureTask$Sync
|    166 | run . . . in java.util.concurrent.FutureTask
|   1110 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    603 | run . . . in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run       in java.lang.Thread

Caused by ClassNotFoundException: com.mysql.jdbc.Driver
->>  366 | run       in java.net.URLClassLoader$1
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    355 | run       in     ''
|    354 | findClass in java.net.URLClassLoader
|    423 | loadClass in java.lang.ClassLoader
|    356 | loadClass in     ''
|   1420 | createConnectionFactory in org.apache.commons.dbcp.BasicDataSource
|   1371 | createDataSource in     ''
|   1044 | getConnection in     ''
|    334 | innerRun  in java.util.concurrent.FutureTask$Sync
|    166 | run       in java.util.concurrent.FutureTask
|   1110 | runWorker in java.util.concurrent.ThreadPoolExecutor
|    603 | run       in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . in java.lang.Thread

---

当jar文件在Maven存储库中可用时，不应该将其复制到lib目录中——最好下载一次并缓存它，而不是在每个项目中都有多个副本。事实上，MySQL驱动程序就是我们在生成的BuildConfig.groovy中使用的示例。只需取消注释并更新版本：

dependencies {
   runtime 'mysql:mysql-connector-java:5.1.22'
}

---

如果您确实有一个不在Maven repo中的jar文件，请将其放在lib目录中。但是Grails不会自动发现它，因此您需要运行

Grails compile--refresh dependencies

当jar文件在Maven存储库中可用时，您不应该将其复制到lib目录中—最好下载一次并缓存它，而不是在每个项目中都有一个副本。事实上，MySQL驱动程序就是我们在生成的BuildConfig.groovy中使用的示例。只需取消注释并更新版本：

dependencies {
   runtime 'mysql:mysql-connector-java:5.1.22'
}

如果您确实有一个不在Maven repo中的jar文件，请将其放在lib目录中。但是Grails不会自动发现它，所以您需要运行

Grails compile--refresh dependencies