使用 new 关键字创建的 Spring bean (@Component) 中的自动装配 [英] Autowiring in Spring bean (@Component) created with new keyword

问题描述

我有两个春豆如下:

@Component("A")
@Scope("prototype")
public class A extends TimerTask {

    @Autowired
    private CampaignDao campaignDao;
    @Autowired
    private CampaignManager campManger;
    A(){
        init_A();
       }
    }

由于遗留代码，我必须使用 new 关键字创建 A 的新对象

I have to make a new object of A with new keyword, due to a legacy code

@Component("B")
@Scope("prototype")
public class B{
     public void test(){
       A a = new A();
     }
}

运行时 -> 类 A 中的 spring bean 为空，我可以创建 spring bean A 的新实例并仍然在其中使用自动装配吗?

when Running -> the spring beans in the class A are null, can i create a new instance of the spring bean A and still use autowiring in it ?

推荐答案

您的组件A"不是由 Spring 容器创建的，因此没有注入依赖项.但是，如果您需要支持一些遗留代码(我从您的问题中了解到)，您可以使用 @Configurable 注释和构建/编译时编织:

Yours component "A" is not created by Spring container, thus, dependencies are not injected. However, if you need to support some legacy code (as I understand from your question), you can use @Configurable annotation and build/compile time weaving:

@Configurable(autowire = Autowire.BY_TYPE)
public class A extends TimerTask {
  // (...)
}

然后，Spring 会将自动装配的依赖项注入到组件 A 中，无论它是由容器本身实例化的，还是由 new 在某些遗留代码中实例化的.

Then, Spring will inject autowired dependencies to component A, no matter if it's instantiated by container itself, or if it's instantiated in some legacy code by new.

例如，要使用 maven 插件设置构建时编织，您必须:

For example, to set up build-time weaving with maven plugin you have to:

1. 添加到Spring应用上下文
2. 配置Maven AspectJ插件:

1. Add <context:spring-configured/> to the Spring application context
2. Configure Maven AspectJ plugin:

在构建插件部分:

<build>
  <plugins>
    <plugin>
      <groupId>org.codehaus.mojo</groupId>
      <artifactId>aspectj-maven-plugin</artifactId>
      <version>1.4</version>
      <configuration>
        <complianceLevel>1.6</complianceLevel>
        <encoding>UTF-8</encoding>
        <aspectLibraries>
          <aspectLibrary>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
          </aspectLibrary>
        </aspectLibraries>
        <!-- 
          Xlint set to warning alleviate some issues, such as SPR-6819. 
          Please consider it as optional.
          https://jira.springsource.org/browse/SPR-6819
        -->
        <Xlint>warning</Xlint>
      </configuration>
      <executions>
        <execution>
          <goals>
            <goal>compile</goal>
            <goal>test-compile</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

...以及依赖项部分:

...and the dependencies section:

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-aspects</artifactId>
  <version>3.1.1.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.aspectj</groupId>
  <artifactId>aspectjrt</artifactId>
  <version>1.6.11</version>
</dependency>

请参阅 Spring 参考以了解更多详细信息:http://static.springsource.org/spring/docs/current/spring-framework-reference/html/aop.html#aop-atconfigurable

Please consult Spring reference for more details: http://static.springsource.org/spring/docs/current/spring-framework-reference/html/aop.html#aop-atconfigurable

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