java程式很大一部分要操作資料庫，為了提高效能操作資料庫的時候，有不得不使用資料庫連線池。資料庫連線池有很多選擇，c3p、dhcp、proxool等，druid作為一名後起之秀，憑藉其出色的效能，也逐漸印入了大家的眼簾。接下來本教程就說一下druid的簡單使用。

和dbcp類似，druid的配置項如下

表1.1 配置屬性

加入 druid-1.0.9.jar

ApplicationContext.xml

< 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 >

  <!-- 阿里 druid 資料庫連線池 -->
    < bean id = "dataSource" class = "com.alibaba.druid.pool.DruidDataSource"destroy-method = "close" >  
         <!-- 資料庫基本資訊配置 -->
         < property name = "url" value = "${url}" />  
         < property name = "username" value = "${username}" />  
         < property name = "password" value = "${password}" />  
         < property name = "driverClassName" value = "${driverClassName}" />  
         < property name = "filters" value = "${filters}" />  
          <!-- 最大併發連線數 -->
         < property name = "maxActive" value = "${maxActive}" />
         <!-- 初始化連線數量 -->
         < property name = "initialSize" value = "${initialSize}" />
         <!-- 配置獲取連線等待超時的時間 -->
         < property name = "maxWait" value = "${maxWait}" />
         <!-- 最小空閒連線數 -->
         < property name = "minIdle" value = "${minIdle}" />  
         <!-- 配置間隔多久才進行一次檢測，檢測需要關閉的空閒連線，單位是毫秒 -->
         < property name = "timeBetweenEvictionRunsMillis" value ="${timeBetweenEvictionRunsMillis}" />
         <!-- 配置一個連線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}" />
         <!-- 開啟 removeAbandoned 功能 -->
         < property name = "removeAbandoned" value = "${removeAbandoned}" />
         <!-- 1800 秒，也就是 30 分鐘 -->
         < property name = "removeAbandonedTimeout" value ="${removeAbandonedTimeout}" />
         <!-- 關閉 abanded 連線時輸出錯誤日誌 -->   
         < 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

  <!-- 連線池 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 >
    <!-- 連線池 啟用 Web 監控統計功能    end-->

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