如何使用@Autowired像工厂模式一样动态注入实现 [英] How to use @Autowired to dynamically inject implementation like a factory pattern

问题描述

我对Sprint还是一个新手，正在为我的应用程序使用Spring 3.x和roo1.1.1.

I am fairly new to Sprint and am using Spring 3.x and roo1.1.1 for my application.

我有一个接口的多种实现，可以@Autowired到其他不同的类中.我只能在运行时决定要使用哪种实现.这应该通过工厂模式来实现.

I have multiple implementation of an interface which would be @Autowired into other different classes. I would only be able to decide which implementation to go with at the runtime. This should be achieved with like a factory pattern.

public interface SomeInterface {
    public void doSomething();
}

实施1.

public class SomeOb implements SomeInterface {
    public void doSomething() {
        //Do something for first implementation here
    }
}

实施2.

public class SomeOtherOb implements SomeInterface {
    public void doSomething() {
        //Do something for first implementation here
    }
}

现在在我的服务中，我需要像这样的自动接线

Now in my service i needed this Autowired like

@Service 
public class MyService {

   @Autowired
   SomeInterface ob;
   //Rest of the code here

}

1)选择要自动接线的实现的逻辑仅知道运行时，因此我无法使用@Qualifier注释对此进行限定. 2)我试图创建一个像

1) The logic to choose which implementation to be Autowired is only know runtime, so i cannot use the @Qualifier annotation to qualify this. 2) I tried to create a FactoryBean like

public class SomeFactoryBean implements FactoryBean<SomeInterface> {
@Override
public SomeInterface getObject() throws Exception {
    if(/*Somecondition*/) {
        return new SomeOb();
    } else
        return new SomeOtherOb();
}

@Override
public Class<? extends SomeInterface> getObjectType() {
    if(/*Somecondition*/) {
        return SomeOb.class;
    } else
        return SomeOtherOb.class;
}

@Override
public boolean isSingleton() {
    return false;
}
}

在applicationContext.xml中，我提到了标签.

In the applicationContext.xml i have the tag mentioned.

当我运行网络服务器时，我会遇到类似

When i run the webserver i run into an error like

No unique bean of type [com.xxxx.xxxx.SomeInterface] is defined: expected single matching bean but found 3: [xxxx, xxxxxxx, xxxxFactory]

任何人都可以帮助我解决此问题.如果我没有正确执行此操作，请指示我正确执行此操作.

Can anyone please help me to resolve this issue. If i am not doing this right please direct me to do this the right way.

感谢并感谢您的帮助， jjk

Thanks and appreciate any help, jjk

推荐答案

感谢您的建议.在同事的帮助下，我得以解决了这个问题.我做错了

Thanks for the suggestion. I was able to solve the problem with help from a colleague. What i was doing wrong

1. 我使用@Service实现了SomeInterface.因此，弹簧扫描器将其拾取并添加到Bean中.
2. 在反复试验中，我从FactoryBean实现中删除了@Component注释.

进行了这些更改后，它就像是一种魅力.

After making these changes it worked like a charm.

这篇关于如何使用@Autowired像工厂模式一样动态注入实现的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！