Wildfly and auto reconnect to the database

问题

I've got a client, a server and a database. The client communicates with the server via a EJB remote interfaces. As the server - I use a Wildfly 8.2.0. As the database - I use a MySQL. The server communicates with the MySQL via a JPA/Hibernate. When I turn off the MySQL server - the Wildfly throws an exception, of course. But when I turn on the MySQL again - the Wildfly still throws the same ERROR. I've to turn off the Wildfly and turn it back that the Wildfly reconnect to the database.

How to set auto reconnect in the Wildfly?

I tried to set auto reconnect in a connection URL: jdbc:mysql://localhost/db?autoReconnect=true&useUnicode=yes&characterEncoding=UTF8 and i tried to add to the standalone-full.xml file which i use, this line: <check-valid-connection-sql>select 1</check-valid-connection-sql>, but both solutions don't work.

standalone-full.xml:

<!-- ... -->
<datasource jta="true" jndi-name="java:jboss/datasources/MySQLDS" pool-name="MySQLDS" enabled="true" use-ccm="true">
    <connection-url>jdbc:mysql://localhost/db?autoReconnect=true&amp;amp;useUnicode=yes&amp;amp;characterEncoding=UTF8</connection-url>
    <driver-class>com.mysql.jdbc.Driver</driver-class>
    <driver>mysqlDriver</driver>
    <security>
        <user-name>user</user-name>
        <password>***</password>
    </security>
    <validation>
        <check-valid-connection-sql>select 1</check-valid-connection-sql>
        <validate-on-match>false</validate-on-match>
        <background-validation>false</background-validation>
    </validation>
    <timeout>
        <set-tx-query-timeout>false</set-tx-query-timeout>
        <blocking-timeout-millis>0</blocking-timeout-millis>
        <idle-timeout-minutes>0</idle-timeout-minutes>
        <query-timeout>0</query-timeout>
        <use-try-lock>0</use-try-lock>
        <allocation-retry>0</allocation-retry>
        <allocation-retry-wait-millis>0</allocation-retry-wait-millis>
    </timeout>
    <statement>
        <share-prepared-statements>false</share-prepared-statements>
    </statement>
</datasource>
<drivers>
    <driver name="mysqlDriver" module="com.mysql">
        <xa-datasource-class>com.mysql.jdbc.Driver</xa-datasource-class>
    </driver>
</drivers>
<!-- ... -->

回答1:

This working on Wildfly 8.1:

         <datasource jta="true" jndi-name="java:jboss/datasources/xxxdb" pool-name="xxxxDB" enabled="true" use-ccm="false">
          <connection-url>jdbc:mysql://localhost:3306/xxxdb?autoReconnect=true&amp;amp;useUnicode=true&amp;amp;characterEncoding=UTF-8</connection-url>
          <driver-class>com.mysql.jdbc.Driver</driver-class>
          <driver>mysql-connector-java-5.1.26-bin.jar</driver>
          <security>
              <user-name>xxxuser</user-name>
              <password>xxxpassword</password>
          </security>
          <validation>
              <check-valid-connection-sql>select 1</check-valid-connection-sql>
              <validate-on-match>false</validate-on-match>
              <background-validation>true</background-validation>
              <background-validation-millis>10000</background-validation-millis>
          </validation>
          <statement>
              <share-prepared-statements>false</share-prepared-statements>
          </statement>
        </datasource>

回答2:

I solved this problem by changing the validate-on-match value to true in my standalone-full.xml file:

<validate-on-match>true</validate-on-match>

回答3:

You can set <background-validation> to true , because this option has better performance , and set <validate-on-match> to false

来源：https://stackoverflow.com/questions/28707650/wildfly-and-auto-reconnect-to-the-database