3回答

• 

  翔仔

  2020-08-29 01:47:16

  适合的，因为底层的源码核心部分基本是不变的。

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• 

  慕桂英7577204

  2020-08-31 23:26:45

  然后，在applications.properties中更改:

  #DataSource
  #数据库驱动
  jdbc.driver=
  #数据库链接
  jdbc.url=jdbc:mysql://localhost:3306/wxbookmark?useUnicode=true&characterEncoding=utf8mb4&useSSL=false
  #数据库用户名
  jdbc.username=wxbookmark
  #数据库密码
  jdbc.password=1234

  再运行，还是会出错如下：

  
  

  org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: 

  ### Error querying database.  Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!

  ### The error may exist in file [C:\Code\Spring\wx-bookmark\target\classes\mapper\UserDao.xml]

  ### The error may involve com.kamuda.wxbookmark.dao.UserDao.queryUserByUid

  ### The error occurred while executing a query

  ### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!

  
  

  1 0

  慕桂英757...

  抱歉，上述描述有误，您原始课程里面的applications.properties配置： jdbc.driver=com.mysql.jdbc.Driver 需要改成： jdbc.driver=com.mysql.cj.jdbc.Driver

  2020-08-31 23:30:44

  共 1 条回复 >

• 

  慕桂英7577204

  2020-08-31 23:19:23

  谢谢，按照您的配置C3P0，com.mysql.jdbc.Driver:

  
  

  <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <scope>runtime</scope>
  </dependency>
  <!-- 连接池 -->
  <dependency>
      <groupId>com.mchange</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.5.5</version>
  </dependency>

  
  

  会出现以下报错

  
  

  2020-08-31 23:11:59.648  INFO 12008 --- [           main] c.m.v.c.i.AbstractPoolBackedDataSource   : Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, contextClassLoaderSource -> caller, dataSourceName -> 1hgemqzacj5yw5okhqb33|6cd166b8, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> 1hgemqzacj5yw5okhqb33|6cd166b8, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql://localhost:3306/wxbookmark?useUnicode=true&characterEncoding=utf8mb4&useSSL=false, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, preferredTestQuery -> null, privilegeSpawnedThreads -> false, properties -> {password=******, user=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]

  Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.

  
  

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