Hibernate+C3P0下連線超時總結
阿新 • • 發佈：2019-02-04
最近後臺總是會遇到當幾個遊戲區併發通知後臺寫入統計資料時，發生連線已超時的問題，丟擲如下異常，導致一些統計資料未有寫進去.
Mysql伺服器預設的“wait_timeout”是8小時【也就是預設的值預設是28800秒】，也就是說一個connection空閒超過8個小時，Mysql將自動斷開該connection，通俗的講就是一個連線在8小時內沒有活動，就會自動斷開該連線。
wait timeout的值可以設定，但最多隻能是2147483，不能再大了。也就是約24.85天
這個引數大致的意思是這樣：當一個客戶端連線到MySQL資料庫後，如果客戶端不自己斷開，也不做任何操作，MySQL資料庫會將這個連線保留"wait_timeout"這麼長時間（單位是s，預設是28800s，也就是8小時），超過這個時間之後，MySQL資料庫為了節省資源，就會在資料庫端斷開這個連線；當然，在此過程中，如果客戶端在這個連線上有任意的操作，MySQL資料庫都會重新開始計算這個時間。
這麼看來，發生上面Exception的原因就是因為我的伺服器和MySQL資料庫的連線超過了”wait_timeout"時間，MySQL伺服器端將其斷開了，但是我的程式再次使用這個連線時沒有做任何判斷，所以就掛了。
異常日誌如下:Caused by: org.hibernate.TransactionException: JDBC begin transaction failed: at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:76) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1392) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.springframework.orm.hibernate4.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:473) ~[spring-orm-3.2.6.RELEASE.jar:3.2.6.RELEASE] ... 15 more Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet successfully received from the server was 3,599,995 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago.
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 22,312,103 milliseconds ago. The last packet sent successfully to the server was 22,312,105 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem. at sun.reflect.GeneratedConstructorAccessor137.newInstance(Unknown Source) ~[?:?] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:1.7.0_65] at java.lang.reflect.Constructor.newInstance(Constructor.java:526) ~[?:1.7.0_65] at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3941) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2551) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2731) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2812) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:5339) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mchange.v2.c3p0.impl.NewProxyConnection.setAutoCommit(NewProxyConnection.java:912) ~[c3p0-0.9.2.1.jar:0.9.2.1] at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:72) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1392) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.springframework.orm.hibernate4.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:473) ~[spring-orm-3.2.6.RELEASE.jar:3.2.6.RELEASE] ... 21 more Caused by: java.net.SocketException: 斷開的管道 at java.net.SocketOutputStream.socketWrite0(Native Method) ~[?:1.7.0_65] at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:113) ~[?:1.7.0_65] at java.net.SocketOutputStream.write(SocketOutputStream.java:159) ~[?:1.7.0_65] at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82) ~[?:1.7.0_65] at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140) ~[?:1.7.0_65] at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3922) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2551) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2731) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2812) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:5339) ~[mysql-connector-java-5.1.26-bin.jar:?] at com.mchange.v2.c3p0.impl.NewProxyConnection.setAutoCommit(NewProxyConnection.java:912) ~[c3p0-0.9.2.1.jar:0.9.2.1] at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:72) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1392) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final] at org.springframework.orm.hibernate4.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:473) ~[spring-orm-3.2.6.RELEASE.jar:3.2.6.RELEASE] ... 21 more
以下是我做的C3P0配置，問題解決:
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
destroy-method="close">
<property name="jdbcUrl" value="jdbc:mysql://192.168.1.21:3306/game_admin?autoReconnect=true&useUnicode=true&characterEncoding=utf-8"/>
<property name="driverClass" value="com.mysql.jdbc.Driver"/>
<property name="user" value="linyu"/>
<property name="password" value="com.123"/>
<!-- 初始化連線池中的連線數，取值應在minPoolSize與maxPoolSize之間，預設為3-->
<property name="initialPoolSize" value="2"/>
<!-- 連線池中保留的最小連線數，預設為：3-->
<property name="minPoolSize" value="2"/>
<!--連線池中保留的最大連線數。預設值: 15 -->
<property name="maxPoolSize" value="15"/>
<!--當連線池中的連線耗盡的時候c3p0一次同時獲取的連線數。預設值: 3 -->
<property name="acquireIncrement" value="2"/>
<!--定義在從資料庫獲取新連線失敗後重復嘗試的次數。預設值: 30 ；小於等於0表示無限次-->
<property name="acquireRetryAttempts" value="0"/>
<!--重新嘗試的時間間隔，預設為：1000毫秒-->
<property name="acquireRetryDelay" value="1000" />
<!--最大空閒時間，3600秒內未使用則連線被丟棄。若為0則永不丟棄。預設值: 0 -->
<property name="maxIdleTime" value="3600"/>
<!--c3p0全域性的PreparedStatements快取的大小。如果maxStatements與maxStatementsPerConnection均為0，則快取不生效，只要有一個不為0，則語句的快取就能生效。如果預設值: 0-->
<property name="maxStatements" value="0"/>
<!--maxStatementsPerConnection定義了連線池內單個連線所擁有的最大快取statements數。預設值: 0 -->
<property name="maxStatementsPerConnection" value="0"/>
<!--定義所有連線測試都執行的測試語句。在使用連線測試的情況下這個一顯著提高測試速度。測試的表必須在初始資料來源的時候就存在。Default: null-->
<property name="preferredTestQuery" value="select 1"/>
<!--每1800秒檢查所有連線池中的空閒連線。Default: 0 -->
<property name="idleConnectionTestPeriod" value="1800"/>
<!-- 獲取連線時測試有效性，每次都驗證連線是否可用 -->
<property name="testConnectionOnCheckout" value="false"/>
</bean></span>由於我配置的是C3P0的配置，和hibernate下進行C3P0配置不同，這個要注意
c3p0.maxIdleTime=hibernate.c3p0.timeout
配置是否生效請參考：com.mchange.v2.c3p0.ComboPooledDataSource 這個類
參考: