springboot(二十)：数据库连接池介绍

概述

1. 性能方面 hikariCP>druid>tomcat-jdbc>dbcp>c3p0 。hikariCP的高性能得益于最大限度的避免锁竞争。
2. druid功能最为全面，sql拦截等功能，统计数据较为全面，具有良好的扩展性。
3. 综合考虑到目前venus已经支持druid且hikariCP并未发现有太多大规模的生产实践的案例，后续将推荐使用druid并把codegen生成的代码默认连接池为druid。
4. 可开启prepareStatement缓存，对性能会有大概10%的提升。

Druid

application.properties

#mybatis-mysql-druid
mybatis.mapper-locations="classpath:mapper/*.xml"
mybatis.config-location="classpath:mapper/config/mybatis-config.xml"
mybatis.type-aliases-package="com.bitauto.oa.purchase.pojo"
spring.datasource.url = jdbc:mysql://127.0.0.1:3306/purchase?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.driverClassName = com.mysql.cj.jdbc.Driver
#spring.datasource.type=com.alibaba.druid.pool.DruidDataSource

mybatis-mysql-druid

PurchaseApplication

package com.bitauto.oa.purchase;

import com.alibaba.druid.pool.DruidDataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.core.env.Environment;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
@MapperScan("com.bitauto.oa.purchase.mapper")
public class PurchaseApplication {

    public static void main(String[] args) {
        SpringApplication.run(PurchaseApplication.class, args);
    }

    @Autowired
    private Environment env;
    //datasource注入  destroy-method="close"的作用是当数据库连接不使用的时候,就把该连接重新放到数据池中,方便下次使用调用.
    @Bean(initMethod = "init", destroyMethod = "close")
    @ConfigurationProperties(prefix = "spring.datasource")
    public DruidDataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(env.getProperty("spring.datasource.url"));
        dataSource.setUsername(env.getProperty("spring.datasource.username"));//用户名
        dataSource.setPassword(env.getProperty("spring.datasource.password"));//密码
        dataSource.setDriverClassName(env.getProperty("spring.datasource.driver-class-name"));
        dataSource.setInitialSize(2);//初始化时建立物理连接的个数
        dataSource.setMaxActive(20);//最大连接池数量
        dataSource.setMinIdle(0);//最小连接池数量
        dataSource.setMaxWait(60000);//获取连接时最大等待时间，单位毫秒。
        dataSource.setValidationQuery("SELECT 1");//用来检测连接是否有效的sql
        dataSource.setTestOnBorrow(false);//申请连接时执行validationQuery检测连接是否有效
        dataSource.setTestWhileIdle(true);//建议配置为true，不影响性能，并且保证安全性。
        dataSource.setPoolPreparedStatements(false);//是否缓存preparedStatement，也就是PSCache
        return dataSource;
    }

    //mybatis SQLSession注入
    @Bean
    public SqlSessionFactory sqlSessionFactoryBean() throws Exception {
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource());
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath*:/mapper/*Mapper.xml"));
        return sqlSessionFactoryBean.getObject();
    }

    //事务支持
    @Bean
    public PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dataSource());
    }
}

PurchaseApplication

HikariCP

资料

http://www.pianshen.com/article/161236925/

https://blog.csdn.net/benben_2015/article/details/78660501