在resources.groovy中定义多个dataSource

Question

I am trying to create multiple dataSource in DataSource.groovy something like:

[1..9].each {
   "dataSource_db$it" {
      driverClassName = 'oracle.jdbc.OracleDriver'
      username = 'xxx${it}xx'
      password = 'xxx${it}xx'
      url = 'jdbc:oracle:thin:@xxx:xxx:xxx'
   }
}

But this is not working. Seems like groovy code is not working in DataSource.groovy. So, I used another alternative to move this to resources.groovy by specifying beans:

import org.apache.commons.dbcp.BasicDataSource
// Place your Spring DSL code here
beans = {
    [1..9].each {
       "dataSource_db$it"(BasicDataSource) {
       driverClassName = 'oracle.jdbc.OracleDriver'
       username = 'xxx${it}xx'
       password = 'xxx${it}xx'
       url = 'jdbc:oracle:thin:@xxx:xxx:xxx'
    }
  }
}

But I got another issue where BasicDataSource is not recognized. Which plugin do I need to install? Is my approach correct? I am using Grails 2.4.3.

Answer 1

We switched from the Commons pool to the the much more performant Tomcat JDBC Connection Pool a while back. It uses most of the same syntax as the Commons pool, so it had the added benefit of being a drop-in replacement that usually requires no config changes other than the driver class name. It's developed by the Tomcat team but doesn't require any Tomcat dependencies, and can be used in any servlet container.

The class name to use with this pool implementation is org.apache.tomcat.jdbc.pool.DataSource , so if you change to that in resources.groovy and you'll get past that issue.

If you keep the DataSource.groovy version and run grails console , then execute

for (name in ctx.beanDefinitionNames.sort()) {
   println name
}

you'll see that you end up with only a second bean with a very odd name:

dataSource_db[1, 2, 3, 4, 5, 6, 7, 8, 9]

(plus all of the other secondary beans that are created for each DataSource with similar suffixes).

The same thing happens in resources.groovy after you fix the class name; I assume the problem here is that the Spring beans DSL handler is interfering with Groovy code that would otherwise work; I was able to get it working with a regular for loop:

for (int i = 1; i < 10; i++) {
   "dataSource_db$i"(BasicDataSource) {
      driverClassName = 'oracle.jdbc.OracleDriver'
      username = 'xxx${it}xx'
      password = 'xxx${it}xx'
      url = 'jdbc:oracle:thin:@xxx:xxx:xxx'
   }
}