grails dbcp闲置连接超时问题的原因和解决之道
引用 http://java.dzone.com/news/database-connection-pooling

dataSource {
    configClass = GrailsAnnotationConfiguration.class
    pooled = true
    driverClassName = "com.mysql.jdbc.Driver"
    //driverClassName = "com.p6spy.engine.spy.P6SpyDriver" // use this driver to enable p6spy logging
    username = "root"
    password = ""
    dialect = "org.hibernate.dialect.MySQL5InnoDBDialect"
    properties {
        minEvictableIdleTimeMillis=1800000
        timeBetweenEvictionRunsMillis=1800000
        numTestsPerEvictionRun=3
        testOnBorrow=true
        testWhileIdle=true
        testOnReturn=true
        validationQuery="SELECT 1"
    }
}