mysql重連，連接丟失

報錯內容：

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException:Communications link failure

Last packet sent to the server was 0 msago.
        atsun.reflect.GeneratedConstructorAccessor98.newInstance(Unknown Source) ~[na:na]
        atsun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)~[na:1.7.0_80]
        atjava.lang.reflect.Constructor.newInstance(Constructor.java:526) ~[na:1.7.0_80]
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)~[MySQL-connector-java-5.1.jar:na]

       atcom.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)~[MySQL-connector-java-5.1.jar:na]

解決辦法：

如果使用Spring的DBCP連接池，在datasource中增加屬性validationQuery和testOnBorrow，如：

<bean id="vrsRankDataSource"class="org.apache.commons.dbcp.BasicDataSource"destroy-method="close">

   <property name="driverClassName"value="${jdbc.driverClassName}" />

   <property name="url" value="${countNew.jdbc.url}"/>

   <property name="username"value="${countNew.jdbc.user}" />

   <property name="password"value="${countNew.jdbc.pwd}" />

   <property name="validationQuery" value="SELECT 1"/>

   <property name="testOnBorrow" value="true"/>

</bean>

如果使用Spring的c3p0連接池，在datasource中添加屬性testConnectionOnCheckin和testConnectionOnCheckout，如：

<bean name="cacheCloudDB"class="com.mchange.v2.c3p0.ComboPooledDataSource">

   <property name="driverClass"value="${jdbc.driver}"/>

   <property name="jdbcUrl"value="${cache.url}"/>

   <property name="user" value="${cache.user}"/>

   <property name="password"value="${cache.password}"/>

   <property name="initialPoolSize" value="10"/>

   <property name="maxPoolSize"value="${cache.maxPoolSize}"/>

   <property name="testConnectionOnCheckin" value="false"/>

   <property name="testConnectionOnCheckout"value="true"/>

   <property name="preferredTestQuery" value="SELECT1"/>

</bean>