druid，为监控而生的数据库连接池，能够提供强大的监控和扩展功能。由于druid有对sql执行的监控功能，项目中使用的连接池由c3p0更换为druid，各种连接池性能对比测试。
配置依赖
<!-- http://www.mvnrepository.com/artifact/com.alibaba/druid -->
<druid.version>1.0.18</druid.version>
<!-- druid -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>${druid.version}</version>
</dependency>
配置StatViewServlet
druid内置提供了一个StatViewServlet用于展示druid的统计信息，用途包括
- 提供监控信息展示的html页面
- 提供监控信息的JSON API
StatViewServlet是一个标准的javax.servlet.http.HttpServlet，需要配置在web应用的WEB-INF/web.xml文件中，如下所示。
<!-- StatViewServlet配置，https://github.com/alibaba/druid/wiki/%E9%85%8D%E7%BD%AE_StatViewServlet%E9%85%8D%E7%BD%AE -->
<servlet>
<servlet-name>DruidStatView</servlet-name>
<servlet-class>com.alibaba.druid.support.http.StatViewServlet</servlet-class>
<init-param>
<!-- 允许清空统计数据 -->
<param-name>resetEnable</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<!-- 用户名 -->
<param-name>loginUsername</param-name>
<param-value>druid</param-value>
</init-param>
<init-param>
<!-- 密码 -->
<param-name>loginPassword</param-name>
<param-value>druid</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>DruidStatView</servlet-name>
<url-pattern>/druid/*</url-pattern>
</servlet-mapping>
- 通过
resetEnable参数，可以在监控页面中点击重置，将所有计数器清零、重新计数，赋值为false时关闭重置功能 - 通过
loginUsername、loginPassword这两个初始参数，可以配置监控页面的登录访问密码 - 通过
allow、deny这两个参数，可以进行ip访问控制。allow参数没有配置或者为空时，允许所有ip访问。deny参数优先于allow参数，如果ip在deny列表中，就算在allow列表，访问也会被拒绝 - 根据配置的
url-pattern来访问内置监控页面：http://<host>:<port>/<context>/druid/，本示例中：http://localhost:8080/hospital/druid/
监控登录页面：
配置WebStatFilter
WebStatFilter用于采集web-jdbc关联监控的数据，需要配置在web应用的WEB-INF/web.xml文件中，如下所示。
<!-- Druid数据库连接池，https://github.com/alibaba/druid/wiki/%E5%B8%B8%E8%A7%81%E9%97%AE%E9%A2%98
WebStatFilter配置，https://github.com/alibaba/druid/wiki/%E9%85%8D%E7%BD%AE_%E9%85%8D%E7%BD%AEWebStatFilter -->
<filter>
<filter-name>DruidWebStatFilter</filter-name>
<filter-class>com.alibaba.druid.support.http.WebStatFilter</filter-class>
<init-param>
<param-name>exclusions</param-name>
<param-value>*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*</param-value>
</init-param>
<init-param>
<param-name>sessionStatMaxCount</param-name>
<param-value>1000</param-value>
</init-param>
<init-param>
<param-name>sessionStatEnable</param-name>
<param-value>false</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>DruidWebStatFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
- 通过
exclusions参数，可以排除一些不必要的url，比如.js,/jslib/等 sessionStatMaxCount参数缺省时，默认值：1000sessionStatEnable参数，是否开启session统计功能principalSessionName、principalCookieName、profileEnable等参数的使用详见wiki
配置dataSource
druid.properties
#druid
druid.url=jdbc:mysql://localhost:3306/hospital?useUnicode=true&characterEncoding=UTF-8
druid.username=root
druid.password=XY+AwyimCIuvPl5Njm7buayg8zp7TwIGX7RAufaR9KQnCSpR6fVp2vvA7KQOJYP/VOVPbmT8wyjmvi6GlUDhvA==
druid.decrypt=true
druid.publickey=MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAKgi+EHD6RHDPuzong8eohKCSe66ZwXpr+vYKhqlnYrY0VyMQR9aT2anjdv75GRGEWWMqW4YgpxiCImUnl6vHXECAwEAAQ==
druid.initialSize=1
druid.maxActive=50
druid.minIdle=1
druid.maxWait=10000
druid.timeBetweenEvictionRunsMillis=30000
druid.minEvictableIdleTimeMillis=60000
druid.validationQuery=select 1
druid.testOnBorrow=true
druid.testOnReturn=false
druid.testWhileIdle=true
druid.removeAbandoned=true
druid.removeAbandonedTimeout=1800
druid.logAbandoned=true
druid.poolPreparedStatements=false
druid.maxPoolPreparedStatementPerConnectionSize=20
#if password is encrypted, config is need.
druid.filters=config,wall
spring-datasource-druid.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:task="http://www.springframework.org/schema/task"
xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.2.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-4.2.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-4.2.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd
http://www.springframework.org/schema/task
http://www.springframework.org/schema/task/spring-task-4.2.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-4.2.xsd">
<!-- Druid数据库连接池，http://www.open-open.com/lib/view/open1430558786084.html
http://www.cnblogs.com/wuyun-blog/p/5679073.html -->
<bean name="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
init-method="init" destroy-method="close">
<!-- 基本属性 url、username、password，https://www.oschina.net/question/873438_234580 -->
<property name="url" value="${druid.url}" />
<property name="username" value="${druid.username}" />
<property name="password" value="${druid.password}" />
<!-- 提示Druid数据源需要对数据库密码进行解密，https://github.com/alibaba/druid/wiki/%E4%BD%BF%E7%94%A8ConfigFilter -->
<property name="connectionProperties"
value="config.decrypt=${druid.decrypt};config.decrypt.key=${druid.publickey}" />
<!-- 初始化连接池连接值、连接池中连接最大值、连接池中连接最小值 -->
<property name="initialSize" value="${druid.initialSize}" />
<property name="maxActive" value="${druid.maxActive}" />
<property name="minIdle" value="${druid.minIdle}" />
<!-- 获取连接时等待最大等待时间（毫秒） -->
<property name="maxWait" value="${druid.maxWait}" />
<!-- 1、检测需要关闭的空闲连接的间隔时间（毫秒）.2、testWhileIdle的判断依据. 默认值：60 * 1000L -->
<property name="timeBetweenEvictionRunsMillis" value="${druid.timeBetweenEvictionRunsMillis}" />
<!-- 一个连接在池中的最小生存时间（毫秒），默认值：1000L * 60L * 30L -->
<property name="minEvictableIdleTimeMillis" value="${druid.minEvictableIdleTimeMillis}" />
<!-- 连接有效性测试 -->
<property name="validationQuery" value="${druid.validationQuery}" />
<property name="testOnBorrow" value="${druid.testOnBorrow}" />
<property name="testOnReturn" value="${druid.testOnReturn}" />
<property name="testWhileIdle" value="${druid.testWhileIdle}" />
<!-- 是否强制关闭长时间不使用的连接 -->
<property name="removeAbandoned" value="${druid.removeAbandoned}" />
<!-- 超过*秒关闭空闲连接 -->
<property name="removeAbandonedTimeout" value="${druid.removeAbandonedTimeout}" />
<!-- 将当前关闭动作记录到日志 -->
<property name="logAbandoned" value="${druid.logAbandoned}" />
<!-- 是否缓存preparedStatement（PSCache），默认值：false；指定每个连接上的PSCache的大小，默认值：10 -->
<property name="poolPreparedStatements" value="${druid.poolPreparedStatements}" />
<property name="maxPoolPreparedStatementPerConnectionSize"
value="${druid.maxPoolPreparedStatementPerConnectionSize}" />
<!-- 监控统计拦截的filters，去掉后监控界面SQL无法统计，https://github.com/alibaba/druid/wiki/%E9%85%8D%E7%BD%AE_StatFilter
http://www.cnblogs.com/ansn001/p/4571606.html -->
<property name="filters" value="${druid.filters}" />
<!-- 同时配置filters、proxyFilters时，它们是组合关系并非替换关系 -->
<property name="proxyFilters">
<list>
<ref bean="stat-filter" />
<ref bean="log-filter" />
</list>
</property>
</bean>
<!-- Druid内置提供一个StatFilter，用于统计监控信息 -->
<bean id="stat-filter" class="com.alibaba.druid.filter.stat.StatFilter">
<!-- slowSqlMillis属性用来配置SQL慢的标准，执行时间超过slowSqlMillis的就是慢，默认值：3000毫秒 -->
<property name="slowSqlMillis" value="10000" />
<!-- 通过日志输出执行慢的SQL，默认值：false -->
<property name="logSlowSql" value="true" />
<!-- StatFilter提供SQL统计合并的功能，默认值：false -->
<property name="mergeSql" value="true" />
</bean>
<!-- 输出SQL至日志 -->
<bean id="log-filter" class="com.alibaba.druid.filter.logging.Slf4jLogFilter">
<!-- 是否输出可执行语句，默认值：false -->
<property name="statementExecutableSqlLogEnable" value="false" />
</bean>
</beans>
配置DruidStatInterceptor
druid提供了spring和jdbc的关联监控，com.alibaba.druid.support.spring.stat.DruidStatInterceptor是一个标准的spring MethodInterceptor，可以灵活进行aop配置，此处使用方法名正则匹配拦截配置，按类型拦截配置参见wiki。
spring aop的配置文档：http://static.springsource.org/spring/docs/current/spring-framework-reference/html/aop-api.html
spring-datasource-druid.xml
<!-- Druid和Spring关联监控配置，方法名正则匹配拦截配置，https://github.com/alibaba/druid/wiki/%E9%85%8D%E7%BD%AE_Druid%E5%92%8CSpring%E5%85%B3%E8%81%94%E7%9B%91%E6%8E%A7%E9%85%8D%E7%BD%AE -->
<bean id="druid-stat-interceptor"
class="com.alibaba.druid.support.spring.stat.DruidStatInterceptor">
</bean>
<bean id="druid-stat-pointcut" class="org.springframework.aop.support.JdkRegexpMethodPointcut"
scope="prototype">
<property name="patterns">
<list>
<value>com.song.hospital.service.impl.*ServiceImpl</value>
</list>
</property>
</bean>
<aop:config>
<aop:advisor advice-ref="druid-stat-interceptor"
pointcut-ref="druid-stat-pointcut" />
</aop:config>