SpringBoot整合数据库连接池其实是很简单的，不管是c3p0还是Druid,步骤都一样，都是在pom.xml中加入依赖，在application.yml加入连接信息，再加上一个配置类即可。

一、整合C3P0

1、pom.xml加入如下依赖

<dependency>
    <groupId>com.mchange</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.9.5.2</version>
</dependency>

这里要注意c3p0的版本，有时候版本太低的话跟mybatis整合在一起可能会报错。

2、application.yml加入如下配置

c3p0:
  jdbcUrl: jdbc:mysql://127.0.0.1:3306/weixinser
  user: root
  password: forever
  driverClass: com.mysql.jdbc.Driver
  minPoolSize: 2
  maxPoolSize: 10
  maxIdleTime: 1800000
  acquireIncrement: 3
  maxStatements: 1000
  initialPoolSize: 3
  idleConnectionTestPeriod: 60
  acquireRetryAttempts: 30
  acquireRetryDelay: 1000
  breakAfterAcquireFailure: false
  testConnectionOnCheckout: false

3、新建一个配置类

package cn.forever.config;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
@Configuration
public class DataSourceConfiguration {
    // c3p0 连接池
    @Bean(name = "dataSource")
    @Qualifier(value = "dataSource")
    @Primary
    @ConfigurationProperties(prefix = "c3p0")
    public DataSource dataSource() {
            return         DataSourceBuilder.create().type(com.mchange.v2.c3p0.ComboPooledDataSource.class).build();
    }
}

然后程序就自动回使用c3p0连接池啦

二、整合Druid

其实是一样的模式，但是druid的话可能需要在maven上加入阿里云的镜像

1、pom.xml加入如下依赖

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.12</version>
</dependency>

2、application.yml加入如下配置

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    url: jdbc:mysql://127.0.0.1:3306/sb
    #生产环境
    #username: itweb
    #password: LWHMHM@1205
    #开发环境
    username: root
    password: forever
    driverClassName: com.mysql.jdbc.Driver
    #连接池的配置信息
    initialSize: 5
    minIdle: 5
    maxActive: 20
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true
    maxPoolPreparedStatementPerConnectionSize: 20
    #wall, 去掉这个，不然会报sql injection violation
    filters: stat,log4j
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

3、新建一个配置类

package cn.myforever.blog.config;
import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import javax.sql.DataSource;
import java.sql.SQLException;
@Configuration
public class DruidDataSourceConfiguration {
    @Value("${spring.datasource.url}")
    private String dbUrl;
    @Value("${spring.datasource.username}")
    private String username;
    @Value("${spring.datasource.password}")
    private String password;
    @Value("${spring.datasource.driverClassName}")
    private String driverClassName;
    @Value("${spring.datasource.initialSize}")
    private int initialSize;
    @Value("${spring.datasource.minIdle}")
    private int minIdle;
    @Value("${spring.datasource.maxActive}")
    private int maxActive;
    @Value("${spring.datasource.maxWait}")
    private int maxWait;
    @Value("${spring.datasource.timeBetweenEvictionRunsMillis}")
    private int timeBetweenEvictionRunsMillis;
    @Value("${spring.datasource.minEvictableIdleTimeMillis}")
    private int minEvictableIdleTimeMillis;
    @Value("${spring.datasource.validationQuery}")
    private String validationQuery;
    @Value("${spring.datasource.testWhileIdle}")
    private boolean testWhileIdle;
    @Value("${spring.datasource.testOnBorrow}")
    private boolean testOnBorrow;
    @Value("${spring.datasource.testOnReturn}")
    private boolean testOnReturn;
    @Value("${spring.datasource.poolPreparedStatements}")
    private boolean poolPreparedStatements;
    @Value("${spring.datasource.maxPoolPreparedStatementPerConnectionSize}")
    private int maxPoolPreparedStatementPerConnectionSize;
    @Value("${spring.datasource.filters}")
    private String filters;
    @Value("{spring.datasource.connectionProperties}")
    private String connectionProperties;
    @Bean     //声明其为Bean实例
    @Primary  //在同样的DataSource中，首先使用被标注的DataSource
    public DataSource dataSource() {
        DruidDataSource datasource = new DruidDataSource();
        datasource.setUrl(this.dbUrl);
        datasource.setUsername(username);
        datasource.setPassword(password);
        datasource.setDriverClassName(driverClassName);
        //configuration
        datasource.setInitialSize(initialSize);
        datasource.setMinIdle(minIdle);
        datasource.setMaxActive(maxActive);
        datasource.setMaxWait(maxWait);
        datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setValidationQuery(validationQuery);
        datasource.setTestWhileIdle(testWhileIdle);
        datasource.setTestOnBorrow(testOnBorrow);
        datasource.setTestOnReturn(testOnReturn);
        datasource.setPoolPreparedStatements(poolPreparedStatements);
        datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
        try {
            datasource.setFilters(filters);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        datasource.setConnectionProperties(connectionProperties);
        return datasource;
    }
}

然后程序就自动回使用Druid连接池啦。

结语

用springboot整合连接池的话真的很简单，模式都一样的，但是这里推荐使用Druid