grails - 如何注入(inject)具有单例范围依赖关系的 Grails 2.4.x 服务？

Question

我在 Grails 2.4.5 服务中处理“依赖注入(inject)”的方式是通过 @PostConstruct :

class HappyService {
    final FizzClient fizzClient

    @PostConstruct
    void postConstruct() {
        FizzClient fizzClient = new FizzClientBuilder()
            .withAuth(/* auth stuff */)
            .withOptions(/* complicated options here */)
            .build()
    }
}

我将“依赖注入(inject)”放在引号中，因为这不是真正的依赖注入(inject)，它就像每个服务内部发生的 DI Bootstrap ，嗯。

我现在需要(真正)向同一个 bean/对象的同一个实例注入(inject)多个服务:

class HappyService {
    final FizzClient fizzClient
    final BuzzClient buzzClient // Needs to be the same bean/instance
                                // as injected into GrumpyService below

    @PostConstruct
    void postConstruct() {
        FizzClient fizzClient = new FizzClientBuilder()
            .withAuth(/* auth stuff */)
            .withOptions(/* complicated options here */)
            .build()
    }
}

class GrumpyService {
    final BuzzClient buzzClient // Needs to be the same bean/instance
                                // as injected into HappyService above
}

我该怎么做呢？

Answer 1

首先，您可以像这样编写一个简单的 Groovy 类(在 src/groovy 内):

import grails.util.Holders

class Utils {

    private static FizzClient fizzClient
    private static BuzzClient buzzClient

    static void init() {
        if (fizzClient && buzzClient) {
            return
        }

        def grailsApplication = Holders.getGrailsApplication()

        fizzClient = new FizzClientBuilder()
                .withAuth(/* auth stuff */)
                .withOptions(/* complicated options here */)
                .build()

        buzzClient = fizzClient.getBuzzClient()     // Do whatever you want to get both the fields initialized
    }

    static FizzClient getFizzClient() {
        init()      // Make sure to get them initialized in case service injection happens first
        return fizzClient
    }

    static BuzzClient getBuzzClient() {
        init()
        return buzzClient
    }
}

现在，在您的 Bootstrap.groovy :

class BootStrap {

    def init = { servletContext ->
        Utils.init()
        // your stuff
    }
}

现在，终于在您的服务中:

class HappyService {
    FizzClient fizzClient
    BuzzClient buzzClient

    @PostConstruct
    void postConstruct() {
        fizzClient = Utils.getFizzClient()
        buzzClient = Utils.getBuzzClient()
    }
}

您的 GrumpyService 也是如此.