记：Failed to obtain JDBC Connection； nested exception is java.sql.SQLException: Connections could not

雨点打透心脏的1/2处 2022-09-02 11:38 46阅读 0赞

数据库版本：8.0.x

搭建ssm项目时遇到的问题,使用的是Spring+Mybatis+c3po 学习搭建框架。

遇到：

> 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!

网上搜了终于找到了答案并成功解决，再次总结并希望能帮到遇到同样问题的朋友：

**1.引用外部库 mysql-connector-java-8.0.26**

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<dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.26</version>
            </dependency>

**2. 引入最新版的c3p0**

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDA5NjM1Mw_size_16_color_FFFFFF_t_70_pic_center 1]

<dependency>
        <groupId>com.mchange</groupId>
        <artifactId>c3p0</artifactId>
        <version>0.9.5.5</version>
    </dependency>

**3.连接的驱动地址为"com.mysql.cj.jdbc.Driver"**  
Mysql和mysql-connector都为8.0以上的版本时，连接驱动就不要再用：com.mysql.jdbc.Driver了，要引用com.mysql.cj.jdbc.Driver

**4.建立连接时url的一些参数**

url加上：useJDBCCompliantTimezoneShift=true&serverTimezone=UTC

jdbc.url=jdbc:mysql://localhost:3306/ssmbuild?
    useUnicode=true&useJDBCCompliantTimezoneShift=true&serverTimezone=UTC&characterEncoding=utf8

到此，我的问题已经解决。

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