java - 如何 Autowiring Spring TaskExecutor 创建的线程？

Question

根据Spring's documentation TaskExecutor的使用方法如下:

import org.springframework.core.task.TaskExecutor;

public class TaskExecutorExample {

  private class MessagePrinterTask implements Runnable {

    private String message;

    public MessagePrinterTask(String message) {
      this.message = message;
    }

    public void run() {
      System.out.println(message);
    }

  }

  private TaskExecutor taskExecutor;

  public TaskExecutorExample(TaskExecutor taskExecutor) {
    this.taskExecutor = taskExecutor;
  }

  public void printMessages() {
    for(int i = 0; i < 25; i++) {
      taskExecutor.execute(new MessagePrinterTask("Message" + i));
    }
  }
}

但是，如果 MessagePrinterTask 具有 Autowiring 的依赖关系，它们将不会由 Spring 配置，因为我们在 Spring 的上下文之外实例化我们的 bean(至少我是这样理解的)，即使 Spring 将提供实际的线程创建。 如果 MessagePrinterTask 具有 Autowiring 的依赖关系，我们如何让 Spring 识别它们？ 我尝试了以下修改后的示例，但无济于事(是的， Autowiring 已正确启用):

import org.springframework.core.task.TaskExecutor;

public class TaskExecutorExample {

  @Component
  private class MessagePrinterTask implements Runnable {

    @Autowired
    private autoWiredDependency;

    public void run() {
      autoWiredDependency.doNotThrowNullPointerExceptionPlease();
    }

  }

  private TaskExecutor taskExecutor;

  public TaskExecutorExample(TaskExecutor taskExecutor) {
    this.taskExecutor = taskExecutor;
  }

  public void printMessages() {
    for(int i = 0; i < 25; i++) {
      taskExecutor.execute(new MessagePrinterTask());
    }
  }
}

Answer 1

我认为有两种方法可以解决这个问题:

一个。为任务提供依赖项 - 这样:

class MessagePrinterTask implements Runnable {
    public MessagePrinterTask(ADependency aDependency){
        this.aDependency = aDependency;
    }


    private ADependency aDependency;

    public void run() {
        aDependency.doNotThrowNullPointerExceptionPlease();
    }
}

在你的 TaskExectorExample 中可以是单例:

import org.springframework.core.task.TaskExecutor;

public class TaskExecutorExample {

  @Autowired  private ADependency aDependency;

  @Autowired
  public TaskExecutorExample(TaskExecutor taskExecutor) {
    this.taskExecutor = taskExecutor;
  }

  public void printMessages() {
    for(int i = 0; i < 25; i++) {
      taskExecutor.execute(new MessagePrinterTask(this.aDependency));
    }
  }
}

b.在您的 MesasgePrinterTask 上使用 @Configurable 注释，这将在 MessagePrinterTask 中注入(inject)依赖项，即使它是在 Spring 容器之外实例化的 - 虽然使用 @Configurable 有一些问题(需要 AspectJ):

@Configurable
class MessagePrinterTask implements Runnable {