grails在事务服务中获得lazzy初始化异常

Question

I'm getting a typical hibernate Lazy initialization exception in my transactional service while accessing propert of an object of a SET.

org.hibernate.LazyInitializationException: could not initialize proxy - no Session

class ProductService {
  static transactional = true
  def xyz() {
    def products = Product.list()
    products.each { product ->
      def category = product.categories.asList().first()
      def title = category.title
    }
  }
}

I'm getting exception when accessing the title property of category

Answer 1

xyz is a Closure being invoked by Groovy as if it were a method, but it's not a method. So it's not proxied by Spring (it's just a field), and you get no transactional behavior. There's almost never a good reason to have a public closure in a Service class (inner utility closures are fine).

This should work:

void xyz() {
   for (product in Product.list()) {
       def category = product.categories.asList().first()
       def title = category.title
   }
}