一、项目基础

参考：Springboot+mybatis+mysql8.0

二、依赖引入

        <!--c3p0连接池-->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.2</version>
        </dependency>

三、配置文件修改

####################C3P0数据源配置#############################
#spring.datasource.c3p0.url = jdbc:mysql://192.168.0.12:3306/test?useSSL=false&useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai&rewriteBatchedStatements=true&allowPublicKeyRetrieval=true
spring.datasource.c3p0.jdbcUrl = jdbc:mysql://192.168.0.12:3306/test?useSSL=false&useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai&rewriteBatchedStatements=true&allowPublicKeyRetrieval=true
#spring.datasource.c3p0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.c3p0.driverClass=com.mysql.cj.jdbc.Driver
#spring.datasource.c3p0.driver-class-name=com.mysql.jdbc.Driver
#spring.datasource.c3p0.username=riant
spring.datasource.c3p0.user=riant
##连接池大小管理
##初始化连接数
spring.datasource.c3p0.initialPoolSize=5
##连接池中保留的最小连接数
spring.datasource.c3p0.minPoolSize=3
##连接池中保留的最大连接数
spring.datasource.c3p0.maxPoolSize=10

注意：与无连接池配置项存在几处差异
1、url地址配置项名修改：spring.datasource.c3p0.jdbcUrl
2、驱动器配置项名称修改：spring.datasource.c3p0.driverClass
3、数据库用户名修改：spring.datasource.c3p0.user

四、数据源配置文件类

@Configuration
public class DataSourceConfig {
    @Bean(name = "dataSource")  
    //配置属性,prefix : 前缀 spring.datasource固定
    @ConfigurationProperties(prefix = "spring.datasource.c3p0")
    public DataSource createDataSource(){
        return DataSourceBuilder.create() 
                .type(ComboPooledDataSource.class) // 设置数据源类型
                .build(); 
    }
}

五、测试结果