spring+hibernate：在applicationCOntext.XML中配置C3P0参数说明Attempted to use a closed or broken resource pool

作者：Gausst松鼠会 | 2024-05-26 16:21:08

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attempted to use a closed or broken resource pool

http://blog.csdn.net/feihong247/article/details/7830539

背景：
在项目中遇到下面这个exception

Exception occurred while logging on

Hibernate operation: Cannot open connection; uncategorized SQLException for SQL [???];
SQL state [null]; error code [0]; An SQLException was provoked by the following failure:
com.mchange.v2.resourcepool.ResourcePoolException: Attempted to use a closed or
broken resource pool; nested exception is java.sql.SQLException: An SQLException was
provoked by the following failure: com.mchange.v2.resourcepool.ResourcePoolException:
Attempted to use a closed or broken resource pool

分析：
看字面的意思，是连接池出问题。因为对spring的连接池配置不熟，所以就找到下面的文章。

1 <?xml version="1.0" encoding="UTF-8"?>
  2 <beans xmlns="http://www.springframework.org/schema/beans"
  3     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4     xmlns:jee="http://www.springframework.org/schema/jee"
  5     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
  6             http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.0.xsd">
  7     <bean id="dataSource"
  8         class="com.mchange.v2.c3p0.ComboPooledDataSource"
  9         destroy-method="close">
10         <property name="driverClass">
11             <value>com.mysql.jdbc.Driver</value>
12         </property>
13         <property name="jdbcUrl">
14             <value>jdbc:mysql://192.168.3.110:3306/DBName?useUnicode=true&characterEncoding=GBK</value>
15         </property>
16         <property name="user">
17             <value>root</value>
18         </property>
19         <property name="password">
20             <value>root</value>
21         </property>
22
23 
24         <property name="minPoolSize">
25             <value>5</value>
26         </property>
27
28 
29         <property name="maxPoolSize">
30             <value>30</value>
31         </property>
32
33 
34         <property name="initialPoolSize">
35             <value>10</value>
36         </property>
37
38 
39         <property name="maxIdleTime">
40             <value>60</value>
41         </property>
42
43 
44         <property name="acquireIncrement">
45             <value>5</value>
46         </property>
47
48 
51         <property name="maxStatements">
52             <value>0</value>
53         </property>
54
55 
56         <property name="idleConnectionTestPeriod">
57             <value>60</value>
58         </property>
59
60 
61         <property name="acquireRetryAttempts">
62             <value>30</value>
63         </property>
64
65 
68         <property name="breakAfterAcquireFailure">
69             <value>true</value>
70         </property>
71
72 
75         <property name="testConnectionOnCheckout">
76             <value>false</value>
77         </property>
78     </bean>
79     
80     <bean id="sessionFactory"
81         class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
82         <property name="dataSource">
83             <ref local="dataSource" />
84         </property>
85         <property name="mappingResources">
86             <list>
87                 <value>com/xh/hibernate/vo/User.hbm.xml</value>
88             </list>
89         </property>
90         <property name="hibernateProperties">
91             <props>
92                 <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
93                 <prop key="hibernate.show_sql">true</prop>
94                 <prop key="hibernate.generate_statistics">true</prop>
95                 <prop key="hibernate.connection.release_mode">auto</prop>
96                 <prop key="hibernate.autoReconnect">true</prop>
97             </props>
98         </property>
99     </bean>
100 </beans>

应该是配置的原因。然后有找到这篇个说明

解决这个异常需要修改设置成如下：

<property name="acquireRetryAttempts">
    <value>30</value>
</property>
<property name="acquireRetryDelay">
    <value>100</value>
</property>
<property name="breakAfterAcquireFailure">
    <value>false</value>
</property>
- acquireRetryAttempts
Default: 30
Defines how many times c3p0 will try to acquire a new Connection from the database before giving up.
If this value is less than or equal to zero, c3p0 will keep trying to fetch a Connection indefinitely

- acquireRetryDelay
Default: 1000
Milliseconds, time c3p0 will wait between acquire attempts.

- breakAfterAcquireFailure
Default: false
If true, a pooled DataSource will declare itself broken and be permanently closed
if a Connection cannot be obtained from the database after making acquireRetryAttempts to acquire one.
If false, failure to obtain a Connection will cause all Threads waiting for the pool to acquire a Connection
to throw an Exception, but the DataSource will remain valid, and will attempt to acquire again following a
call to getConnection().

再分析：
为什么会说Attempted to use a closed or broken resource pool，应该是有链接没关闭。因为一直对<session.save>和<geHibernateTemplate().save> 这两种DAO实现方式不理解。找到下面这篇文章
<引用：http://jeoff.blog.51cto.com/186264/133434>

1 自动生成hibernate配置文件的时候，会在dao层用到getSession()方法来操作数据库记录，但是他还有个方法getHibernateTemplate()，这两个方法究竟有什么区别呢？
2 1.使用getSession()方法你只要继承sessionFactory，而使用getHibernateTemplate()方法必须继承 HibernateDaoSupport当然包括sessionFactory，这点区别都不是特别重要的，下面这些区别就很重要了
3 2.getSession()方法是没有经过spring包装的，spring会把最原始的session给你，在使用完之后必须自己调用相应的 close方法，而且也不会对声明式事务进行相应的管理，一旦没有及时关闭连接，就会导致数据库连接池的连接数溢出，getHibernateTemplate()方法是经过spring封装的，例如添加相应的声明式事务管理，由spring管理相应的连接。
4 在实际的使用过程中发现的确getHibernateTemplate()比getSession()方法要好很多，但是有些方法在getHibernateTemplate()并没有提供，这时我们用HibernateCallback 回调的方法管理数据库.

看看黑体标注的那句话，再看看程序代码会发现确实有很多使用session方式的DAO在最后没有关闭。root cause应该就是他了。

总结：
1. 是用session实现DAO，必须要在最后关闭session，不然会导致连接池链接溢出
2.可以使用 set breakAfterAcquireFailure =false 来规避这个问题。

尾巴：
但 set breakAfterAcquireFailure =false 能不能解决问题还需要进一步检验。

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