在使用JPA時，有時候需要設定連線的事務隔離級別，以下幾種方法可供參考。

DataSource source = (javax.sql.DataSource) jndiCntxt.lookup("java:comp/env/jdbc/myds");
Connection con = source.getConnection( );
con.setTransactionIsolation(Connection.TRANSACTION_READ_UNCOMMITTED);

    <bean id="gf.dataSource" class="org.apache.commons.dbcp2.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
        <property name="maxTotal" value="${jdbc.maxConn}"/>
        <property name="DefaultTransactionIsolation" value="1"/>
    </bean>
 

org.hibernate.Session session = (Session)entityManager.getDelegate();
Connection connection = session.connection();
connection.setTransactionIsolation(Connection.READ_UNCOMMITTED);

import org.eclipse.persistence.sessions.DatabaseLogin;
import org.eclipse.persistence.sessions.Session;
import org.eclipse.persistence.sessions.factories.SessionCustomizer;

public class DFSessionCustomizer implements SessionCustomizer {
        @Override
        public void customize(Session session) throws Exception {
            DatabaseLogin databaseLogin = (DatabaseLogin) session.getDatasourceLogin();
            databaseLogin.setTransactionIsolation(DatabaseLogin.TRANSACTION_READ_COMMITTED);
        }
}
 

<property name="eclipselink.session.customizer" value="com.filip.blabla.DFSessionCustomizer"/>

java.sql.Connection connection = entityManager.unwrap(java.sql.Connection.class);
connection.setTransactionIsolation(java.sql.Connection.TRANSACTION_READ_COMMITTED);