一、背景

　　java程序很大一部分要操作數據庫，為了提高性能操作數據庫的時候，又不得不使用數據庫連接池。數據庫連接池有很多選擇，c3p、dhcp、proxool等，druid作為一名後起之秀，憑借其出色的性能，也逐漸映入了大家的眼簾。接下來本教程就說一下druid的簡單使用。

二、jar包下載、配置詳解及配置示例

　　1.jar獲取

　　　　可以從 http://repo1.maven.org/maven2/com/alibaba/druid/ 下載最新的jar包。如果想使用最新的源碼編譯，也可以從 https://github.com/alibaba/druid 下載源碼，然後使用maven命令行，或者導入到IDEA中進行編譯獲得。

　　2.druid的配置項詳解　　

3.配置示例

　　spring.xml文件中加入：

<bean name = "transactionManager" class ="org.springframework.jdbc.datasource.DataSourceTransactionManager" >   
   　　<property name = "dataSource" ref = "dataSource" ></ property >
　　</bean >

    <bean id = "propertyConfigurer" class ="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" >  
       < property name = "locations" >  
           < list >  
                 < value > /WEB-INF/classes/dbconfig.properties </ value >  
            </ list >  
        </ property >  
    </ bean >

    <!-- 阿裏 druid 數據庫連接池 -->
    < bean id = "dataSource" class = "com.alibaba.druid.pool.DruidDataSource"destroy-method = "close" >  
         <!-- 數據庫基本信息配置 -->
         < property name = "url" value = "${url}" />  
         < property name = "username" value = "${username}" />  
         < property name = "password" value = "${password}" />  
         < property name = "driverClassName" value = "${driverClassName}" />  
         < property name = "filters" value = "${filters}" />  

          <!-- 最大並發連接數 -->
         < property name = "maxActive" value = "${maxActive}" />

         <!-- 初始化連接數量 -->
         < property name = "initialSize" value = "${initialSize}" />

         <!-- 配置獲取連接等待超時的時間 -->
         < property name = "maxWait" value = "${maxWait}" />

         <!-- 最小空閑連接數 -->
         < property name = "minIdle" value = "${minIdle}" />  

          <!-- 配置間隔多久才進行一次檢測，檢測需要關閉的空閑連接，單位是毫秒 -->
         < property name = "timeBetweenEvictionRunsMillis" value ="${timeBetweenEvictionRunsMillis}" />

         <!-- 配置一個連接在池中最小生存的時間，單位是毫秒 -->
         < property name = "minEvictableIdleTimeMillis" value ="${minEvictableIdleTimeMillis}" />  

         < property name = "validationQuery" value = "${validationQuery}" />  
         < property name = "testWhileIdle" value = "${testWhileIdle}" />  
         < property name = "testOnBorrow" value = "${testOnBorrow}" />  
         < property name = "testOnReturn" value = "${testOnReturn}" />  
         < property name = "maxOpenPreparedStatements" value ="${maxOpenPreparedStatements}" />

         <!-- 打開 removeAbandoned 功能 -->
         < property name = "removeAbandoned" value = "${removeAbandoned}" />

         <!-- 1800 秒，也就是 30 分鐘 -->
         < property name = "removeAbandonedTimeout" value ="${removeAbandonedTimeout}" />

         <!-- 關閉 abanded 連接時輸出錯誤日誌 -->   
         < property name = "logAbandoned" value = "${logAbandoned}" />
    </ bean >

　　dbconfig.properties

url=jdbc:mysql://localhost:3306/newm

driverClassName=com.mysql.jdbc.Driver

username=root

password=root

filters=stat

maxActive=20

initialSize=1

maxWait=60000

minIdle=10

maxIdle=15

timeBetweenEvictionRunsMillis=60000

minEvictableIdleTimeMillis=300000

validationQuery=SELECT ‘x‘

testWhileIdle=true

testOnBorrow=false

testOnReturn=false

maxOpenPreparedStatements=20

removeAbandoned=true

removeAbandonedTimeout=1800

logAbandoned=true

　　web.xml

<!-- 連接池 啟用 Web 監控統計功能    start-->
    < 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 >
    </ filter >

    < filter-mapping >
       < filter-name > DruidWebStatFilter </ filter-name >
       < url-pattern > /* </ url-pattern >
    </ filter-mapping >

    < servlet >
       < servlet-name > DruidStatView </ servlet-name >
       < servlet-class > com.alibaba.druid.support.http.StatViewServlet </ servlet-class >
    </ servlet >

    < servlet-mapping >
       < servlet-name > DruidStatView </ servlet-name >
       < url-pattern > / druid /* </ url-pattern >
    </ servlet-mapping >
    <!-- 連接池 啟用 Web 監控統計功能    end-->

訪問監控頁面： http://ip:port/projectName/druid/index.html.

阿裏巴巴數據庫連接池 druid配置詳解