依赖注入：条件

Question

这是什么我已经做Grails中一个非常简单的例子：我在寻找这样做的更多的面向对象的方式，像

// this can be a service or normal class 
public abstract class Person { 
    public final String introduceSelf() { 
     return "Hi, I'm " + getFullName() 
    } 

    protected abstract String getFullName() 
} 

// Service 
class AlexService extends Person { 
    protected String getFullName() { 
     return "Alex Goodman" 
    } 
} 

// Service 
class BobService extends Person { 
    protected String getFullName() { 
     return "Bob Goodman" 
    } 
} 

// Service 
class CarlService extends Person { 
    protected String getFullName() { 
     return "Carl Goodman" 
    } 
} 

// Controller 
class IntroduceController { 
    def alex 
    def bob 
    def carl 

    def index() { 
     if(params.person == "a") 
      render alex.introduceSelf() 
     if(params.person == "b") 
      render bob.introduceSelf() 
     if(params.person == "c") 
      render carl.introduceSelf() 
    } 
} 

：

// Controller 
class IntroduceController { 
    def person 

    def index() { 
     // inject a proper person in a more object oriented way 

     render person.introduceSelf() 
    } 
} 

你能否建议如何以更加面向对象/动态的方式实现这一点？

Answer 1

您可以在grails-app/conf/spring/resources.groovy文件中编写person豆的定义。例如：

beans = { 
    person(BobService) 
} 

欲了解更多信息，请查看本：http://grails.org/doc/latest/guide/spring.html#springdslAdditional

Answer 2

class IntroduceController { 

    def grailsApplication 

    def index() { 
    def person = grailsApplication.mainContext.getBean(params.person) 
    person.doSomething() 
    } 

} 

您必须确保，你的服务的名称对应params.person值，params.person = 'bob'会工作，params.person = 'b'不会