>轉載自http://blog.csdn.net/hj7jay/article/details/51686418
Java程式很大一部分要操作資料庫,為了提高性能操作資料庫的時候,有不得不使用資料庫連接配接池。資料庫連接配接池有很多選擇,c3p、dhcp、proxool等,druid作為一名後起之秀,憑借其出色的性能,也逐漸印入了大家的眼簾。接下來本教程就說一下druid的簡單使用。
首先從 http://repo1.maven.org/maven2/com/alibaba/druid/ 下載下傳最新的jar包。如果想使用最新的源碼編譯,可以從 https://github.com/alibaba/druid 下載下傳源碼,然後使用maven指令行,或者導入到eclipse中進行編譯。
和dbcp類似,druid的配置項如下
配置 | 預設值 | 說明 |
name | 配置這個屬性的意義在于,如果存在多個資料源,監控的時候 可以通過名字來區分開來。如果沒有配置,将會生成一個名字, 格式是:”DataSource-” + System.identityHashCode(this) | |
jdbcUrl | 連接配接資料庫的url,不同資料庫不一樣。例如: mysql : jdbc:mysql://10.20.153.104:3306/druid2 oracle : jdbc:oracle:thin:@10.20.149.85:1521:ocnauto | |
username | 連接配接資料庫的使用者名 | |
password | 連接配接資料庫的密碼。如果你不希望密碼直接寫在配置檔案中, 可以使用ConfigFilter。詳細看這裡: https://github.com/alibaba/druid/wiki/%E4%BD%BF%E7%94%A8ConfigFilter | |
driverClassName | 根據url自動識别 | 這一項可配可不配,如果不配置druid會根據url自動識别dbType,然後選擇相應的driverClassName |
initialSize | 初始化時建立實體連接配接的個數。初始化發生在顯示調用init方法,或者第一次getConnection時 | |
maxActive | 8 | 最大連接配接池數量 |
maxIdle | 8 | 已經不再使用,配置了也沒效果 |
minIdle | 最小連接配接池數量 | |
maxWait | 擷取連接配接時最大等待時間,機關毫秒。配置了maxWait之後, 預設啟用公平鎖,并發效率會有所下降, 如果需要可以通過配置useUnfairLock屬性為true使用非公平鎖。 | |
poolPreparedStatements | false | 是否緩存preparedStatement,也就是PSCache。 PSCache對支援遊标的資料庫性能提升巨大,比如說oracle。 在mysql5.5以下的版本中沒有PSCache功能,建議關閉掉。 作者在5.5版本中使用PSCache,通過監控界面發現PSCache有緩存命中率記錄, 該應該是支援PSCache。 |
maxOpenPreparedStatements | -1 | 要啟用PSCache,必須配置大于0,當大于0時, poolPreparedStatements自動觸發修改為true。 在Druid中,不會存在Oracle下PSCache占用記憶體過多的問題, 可以把這個數值配置大一些,比如說100 |
validationQuery | 用來檢測連接配接是否有效的sql,要求是一個查詢語句。 如果validationQuery為null,testOnBorrow、testOnReturn、 testWhileIdle都不會其作用。 | |
testOnBorrow | true | 申請連接配接時執行validationQuery檢測連接配接是否有效,做了這個配置會降低性能。 |
testOnReturn | false | 歸還連接配接時執行validationQuery檢測連接配接是否有效,做了這個配置會降低性能 |
testWhileIdle | false | 建議配置為true,不影響性能,并且保證安全性。 申請連接配接的時候檢測,如果空閑時間大于 timeBetweenEvictionRunsMillis, 執行validationQuery檢測連接配接是否有效。 |
timeBetweenEvictionRunsMillis | 有兩個含義: 1) Destroy線程會檢測連接配接的間隔時間 2) testWhileIdle的判斷依據,詳細看testWhileIdle屬性的說明 | |
numTestsPerEvictionRun | 不再使用,一個DruidDataSource隻支援一個EvictionRun | |
minEvictableIdleTimeMillis | ||
connectionInitSqls | 實體連接配接初始化的時候執行的sql | |
exceptionSorter | 根據dbType自動識别 | 當資料庫抛出一些不可恢複的異常時,抛棄連接配接 |
filters | 屬性類型是字元串,通過别名的方式配置擴充插件, 常用的插件有: 監控統計用的filter:stat 日志用的filter:log4j 防禦sql注入的filter:wall | |
proxyFilters | 類型是List<com.alibaba.druid.filter.Filter>, 如果同時配置了filters和proxyFilters, 是組合關系,并非替換關系 |
表1.1 配置屬性
加入 druid-1.0.9.jar
ApplicationContext.xml
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- < 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 >
< 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 >
ApplicationContext.xml配置druid
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- <!– 阿裡 druid 資料庫連接配接池 –>
- < 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}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class="alt"><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"username"</span><span> </span><span class="attribute">value</span><span> = </span><span class="attribute-value">" />
- < property name = "username" value = "{username}” />
- < property name = “password” value = “{password}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class="alt"><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"driverClassName"</span><span> </span><span class="attribute">value</span><span> = </span><span class="attribute-value">" />
- < property name = "driverClassName" value = "{driverClassName}” />
- < property name = “filters” value = “{filters}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class="alt"><span> <span class="comments"><!-- 最大并發連接配接數 --></span><span> </span></span></li><li class=""><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"maxActive"</span><span> </span><span class="attribute">value</span><span> = </span><span class="attribute-value">" />
- <!-- 最大并發連接配接數 -->
- < property name = "maxActive" value = "{maxActive}” />
- <!– 初始化連接配接數量 –>
- < property name = “initialSize” value = “{initialSize}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class="alt"><span> <span class="comments"><!-- 配置擷取連接配接等待逾時的時間 --></span><span> </span></span></li><li class=""><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"maxWait"</span><span> </span><span class="attribute">value</span><span> = </span><span class="attribute-value">" />
- <!-- 配置擷取連接配接等待逾時的時間 -->
- < property name = "maxWait" value = "{maxWait}” />
- <!– 最小空閑連接配接數 –>
- < property name = “minIdle” value = “{minIdle}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class="alt"><span> <span class="comments"><!-- 配置間隔多久才進行一次檢測,檢測需要關閉的空閑連接配接,機關是毫秒 --></span><span> </span></span></li><li class=""><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"timeBetweenEvictionRunsMillis"</span><span> </span><span class="attribute">value</span><span> =</span><span class="attribute-value">" />
- <!-- 配置間隔多久才進行一次檢測,檢測需要關閉的空閑連接配接,機關是毫秒 -->
- < property name = "timeBetweenEvictionRunsMillis" value ="{timeBetweenEvictionRunsMillis}” />
- <!– 配置一個連接配接在池中最小生存的時間,機關是毫秒 –>
- < property name = “minEvictableIdleTimeMillis” value =“{minEvictableIdleTimeMillis}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class="alt"><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"validationQuery"</span><span> </span><span class="attribute">value</span><span> = </span><span class="attribute-value">" />
- < property name = "validationQuery" value = "{validationQuery}” />
- < property name = “testWhileIdle” value = “{testWhileIdle}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class="alt"><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"testOnBorrow"</span><span> </span><span class="attribute">value</span><span> = </span><span class="attribute-value">" />
- < property name = "testOnBorrow" value = "{testOnBorrow}” />
- < property name = “testOnReturn” value = “{testOnReturn}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class="alt"><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"maxOpenPreparedStatements"</span><span> </span><span class="attribute">value</span><span> =</span><span class="attribute-value">" />
- < property name = "maxOpenPreparedStatements" value ="{maxOpenPreparedStatements}” />
- <!– 打開 removeAbandoned 功能 –>
- < property name = “removeAbandoned” value = “{removeAbandoned}"</span><span> </span><span class="tag">/></span><span> </span></span></li><li class=""><span> <span class="comments"><!-- 1800 秒,也就是 30 分鐘 --></span><span> </span></span></li><li class="alt"><span> <span class="tag"><</span><span> </span><span class="tag-name">property</span><span> </span><span class="attribute">name</span><span> = </span><span class="attribute-value">"removeAbandonedTimeout"</span><span> </span><span class="attribute">value</span><span> =</span><span class="attribute-value">" />
- <!-- 1800 秒,也就是 30 分鐘 -->
- < property name = "removeAbandonedTimeout" value ="{removeAbandonedTimeout}” />
- <!– 關閉 abanded 連接配接時輸出錯誤日志 –>
- < property name = “logAbandoned” value = “${logAbandoned}” />
- </ bean >
<!-- 阿裡 druid 資料庫連接配接池 -->
< bean id = "dataSource" class = "com.alibaba.druid.pool.DruidDataSource"destroy-method = "close" >
<!-- 資料庫基本資訊配置 -->
< property name = "url" value = "${url}" />
< property name = "username" value = "${username}" />
< property name = "password" value = "${password}" />
< property name = "driverClassName" value = "${driverClassName}" />
< property name = "filters" value = "${filters}" />
<!-- 最大并發連接配接數 -->
< property name = "maxActive" value = "${maxActive}" />
<!-- 初始化連接配接數量 -->
< property name = "initialSize" value = "${initialSize}" />
<!-- 配置擷取連接配接等待逾時的時間 -->
< property name = "maxWait" value = "${maxWait}" />
<!-- 最小空閑連接配接數 -->
< property name = "minIdle" value = "${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配接,機關是毫秒 -->
< property name = "timeBetweenEvictionRunsMillis" value ="${timeBetweenEvictionRunsMillis}" />
<!-- 配置一個連接配接在池中最小生存的時間,機關是毫秒 -->
< property name = "minEvictableIdleTimeMillis" value ="${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 ="${removeAbandonedTimeout}" />
<!-- 關閉 abanded 連接配接時輸出錯誤日志 -->
< property name = "logAbandoned" value = "${logAbandoned}" />
</ bean >
dbconfig.properties
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- 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
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
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- <!– 連接配接池 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 >
- <!– 連接配接池 啟用 Web 監控統計功能 end–>
<!-- 連接配接池 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 >
<!-- 連接配接池 啟用 Web 監控統計功能 end-->
通路監控頁面: http://ip:port/projectName/druid/index.html