java對(duì)象池管理方式common-pool2使用
common-pool2 使用
common-pool2提供了3中對(duì)象池管理方式,它們的使用方式基本一樣,這里以GenericObjectPool對(duì)象池為例介紹其使用方式,一般實(shí)現(xiàn)自己的對(duì)象池需要經(jīng)過2個(gè)步驟
- 實(shí)現(xiàn)PooledObjectFactory接口:該接口是一種工廠模式,實(shí)現(xiàn)其目的是讓對(duì)象池通過該工廠模式創(chuàng)建管理的對(duì)象
- 創(chuàng)建對(duì)象池(GenericObjectPool(PooledObjectFactory))實(shí)例
創(chuàng)建Conn對(duì)象池
我們假設(shè)Conn對(duì)象是一個(gè)建立TCP連接的對(duì)象,該對(duì)象的初始化時(shí)間平均為500ms,為了避免在程序中頻繁創(chuàng)建Conn對(duì)象,我們需要借助對(duì)象池管理Conn對(duì)象實(shí)例
import org.slf4j.LoggerFactory; /** * common-pool2 使用方式 * <p/> * 假設(shè)這是一個(gè)建立TCP連接的對(duì)象,該對(duì)象的初始化時(shí)間平均為500ms,為了避免在程序中頻繁創(chuàng)建Conn對(duì)象,我們需要借助對(duì)象池管理Conn對(duì)象實(shí)例 * * @author WangJun <wangjuntytl@163.com> * @version 1.0 15/10/28 * @since 1.6 */ public class Conn { /** * 記錄對(duì)象的創(chuàng)建時(shí)間 */ private long createTime; /** * 初始化Conn對(duì)象,模擬創(chuàng)建Conn對(duì)象平均消耗500ms * @throws InterruptedException */ public Conn() throws InterruptedException { Thread.sleep(500); createTime = System.currentTimeMillis(); LoggerFactory.getLogger(getClass()).debug(" init conn suc... " + createTime); } /** * 報(bào)告Conn對(duì)象信息 */ public void report() { LoggerFactory.getLogger(getClass()).info("this is a available conn " + createTime); } }
工廠模式
利用工廠模式,使對(duì)象池通過該工廠模式創(chuàng)建管理的對(duì)象
package com.peaceful.pool.demo; import org.apache.commons.pool2.BasePooledObjectFactory; import org.apache.commons.pool2.PooledObject; import org.apache.commons.pool2.PooledObjectFactory; import org.apache.commons.pool2.impl.DefaultPooledObject; /** * common-pool2 使用方式 * <p/> * 為了使用common-pool2對(duì)象池管理,我們必須實(shí)現(xiàn){@link org.apache.commons.pool2.PooledObjectFactory}或者其子類 * 這是一個(gè)工廠模式,告訴對(duì)象池怎樣去創(chuàng)建要管理的對(duì)象 * <p/> * BasePooledObjectFactory 是對(duì){@link org.apache.commons.pool2.PooledObjectFactory}的一個(gè)基本實(shí)現(xiàn),我們可以繼承該類,減少一些方法的實(shí)現(xiàn) * <p/> * 在實(shí)現(xiàn){@link org.apache.commons.pool2.PooledObjectFactory}接口時(shí),我們一定要實(shí)現(xiàn)的接口方法是{@link PooledObjectFactory#makeObject()}方法。 * * @author WangJun <wangjuntytl@163.com> * @version 1.0 15/10/28 * @since 1.6 */ public class ConnFactory extends BasePooledObjectFactory<Conn> { /** * 間接實(shí)現(xiàn){@link PooledObjectFactory#makeObject()}方法,表明怎樣創(chuàng)建需要管理對(duì)象 */ @Override public Conn create() throws Exception { return new Conn(); } /** * 在common-pool2中為了統(tǒng)計(jì)管理的對(duì)象的一些信息,比如調(diào)用次數(shù),空閑時(shí)間,上次使用時(shí)間等,需要對(duì)管理的對(duì)象進(jìn)行包裝,然后在放入到對(duì)象池中 * * @param obj 對(duì)象池要管理的對(duì)象 * @return 返回包裝后的PooledObject對(duì)象 */ @Override public PooledObject<Conn> wrap(Conn obj) { return new DefaultPooledObject<Conn>(obj); } }
ConnPool池個(gè)性化配置
為了模擬的更真實(shí),ConnPool池可以讓使用者個(gè)性化配置
package com.peaceful.pool.demo; import org.apache.commons.pool2.impl.GenericObjectPoolConfig; /** * common-pool2 使用方式 * <p/> * {@link org.apache.commons.pool2.impl.GenericObjectPool}支持個(gè)性化配置,我們可以配置對(duì)象池中總共的對(duì)象數(shù),最大、最小空閑對(duì)象數(shù)等等 * 這邊繼承{@link GenericObjectPoolConfig}是為了ConnPool也可以進(jìn)行個(gè)性化的配置 * * @author WangJun <wangjuntytl@163.com> * @version 1.0 15/10/28 * @since 1.6 */ public class ConnPoolConfig extends GenericObjectPoolConfig { public ConnPoolConfig() { // defaults to make your life with connection pool easier :) setMinIdle(5); setTestOnBorrow(true); } }
對(duì)象工廠創(chuàng)建一個(gè)對(duì)象池實(shí)例
有了創(chuàng)建對(duì)象的工廠,我們就可以創(chuàng)建一個(gè)對(duì)象池實(shí)例
package com.peaceful.pool.demo; import org.apache.commons.pool2.impl.GenericObjectPool; /** * common-pool2 使用方式 * <p/> * Conn對(duì)象管理池,這里利用GenericObjectPool作為對(duì)象池 * * @author WangJun <wangjuntytl@163.com> * @version 1.0 15/10/28 * @since 1.6 */ public class ConnPool extends GenericObjectPool<Conn> { /** * 調(diào)用{@link GenericObjectPool}的構(gòu)造方法,構(gòu)造ConnPool */ public ConnPool() { super(new ConnFactory(), new ConnPoolConfig()); } /** * 調(diào)用{@link GenericObjectPool}的構(gòu)造方法,構(gòu)造ConnPool */ public ConnPool(ConnPoolConfig connPoolConfig) { super(new ConnFactory(), connPoolConfig); } }
這樣一個(gè)就完成了整個(gè)ConnPool的編碼,下面我們?cè)趯懸粋€(gè)demo,演示使用ConnPool
public class ConnDemo { public static void main(String[] args) throws Exception { ConnPoolConfig connPoolConfig = new ConnPoolConfig(); connPoolConfig.setMinIdle(5); connPoolConfig.setMaxIdle(8); ConnPool connPool = new ConnPool(connPoolConfig); Conn conn1 = connPool.borrowObject(); Conn conn2 = connPool.borrowObject(); Conn conn3 = connPool.borrowObject(); Conn conn4 = connPool.borrowObject(); Conn conn5 = connPool.borrowObject(); conn1.report(); connPool.returnObject(conn1); conn2.report(); connPool.returnObject(conn2); conn3.report(); connPool.returnObject(conn3); conn4.report(); connPool.returnObject(conn4); conn5.report(); connPool.returnObject(conn5); conn5.report(); // 被歸還的對(duì)象的引用,不可以在次歸還 // java.lang.IllegalStateException: Object has already been retured to this pool or is invalid try { connPool.returnObject(conn5); }catch (Exception e){ e.printStackTrace(); } } }
下面是ConnDemo的運(yùn)行結(jié)果
[2015-10-28 14:56:06 DEBUG] {com.peaceful.pool.demo.Conn:18}- init conn suc...
[2015-10-28 14:56:07 DEBUG] {com.peaceful.pool.demo.Conn:18}- init conn suc...
[2015-10-28 14:56:07 DEBUG] {com.peaceful.pool.demo.Conn:18}- init conn suc...
[2015-10-28 14:56:08 DEBUG] {com.peaceful.pool.demo.Conn:18}- init conn suc...
[2015-10-28 14:56:08 DEBUG] {com.peaceful.pool.demo.Conn:18}- init conn suc...
[2015-10-28 14:56:08 INFO ] {com.peaceful.pool.demo.Conn:22}-this is a available conn 1446015366746
[2015-10-28 14:56:08 INFO ] {com.peaceful.pool.demo.Conn:22}-this is a available conn 1446015367346
[2015-10-28 14:56:08 INFO ] {com.peaceful.pool.demo.Conn:22}-this is a available conn 1446015367853
[2015-10-28 14:56:08 INFO ] {com.peaceful.pool.demo.Conn:22}-this is a available conn 1446015368354
[2015-10-28 14:56:08 INFO ] {com.peaceful.pool.demo.Conn:22}-this is a available conn 1446015368860
[2015-10-28 14:56:08 INFO ] {com.peaceful.pool.demo.Conn:22}-this is a available conn 1446015368860
java.lang.IllegalStateException: Object has already been retured to this pool or is invalid
at org.apache.commons.pool2.impl.GenericObjectPool.returnObject(GenericObjectPool.java:595)
at com.peaceful.pool.demo.ConnDemo.main(ConnDemo.java:37)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
以上就是java對(duì)象池common-pool2使用的詳細(xì)內(nèi)容,更多關(guān)于java對(duì)象池common-pool2的資料請(qǐng)關(guān)注腳本之家其它相關(guān)文章!
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