如何自动装配Spring TaskExecutor创建的线程？ [英] How do I autowire a Spring TaskExecutor created thread?

问题描述

根据 Spring的文档使用TaskExecutor的方法如下：

According to Spring's documentation the way to use the TaskExecutor is as follows:

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已自动装配它们不会被Spring配置它们的依赖关系，因为我们在Spring的上下文之外实例化我们的bean（至少我就是这样理解它），即使Spring会提供实际的线程创建。 如果MessagePrinterTask具有自动连接的依赖关系，我们如何让Spring识别它们？我尝试了以下修改示例无效（是的，正确启用了自动装配）：

However, if MessagePrinterTask has autowired dependencies they will not be configured by Spring because we are instantiating our bean outside of Spring's context (at least that's how I understand it) even though Spring will provide the actual thread creation. If MessagePrinterTask were to have autowired dependencies how do we get Spring to recognize them? I tried the following modified example to no avail (and yes, autowiring is enabled properly):

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());
    }
  }
}

推荐答案

我认为有两种方法可以解决这个问题：

There are two ways I think that you can go about this:

a。提供任务的依赖关系 - 这样：

a. Provide the dependencies to the Task - this way:

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


    private ADependency aDependency;

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

在你的TaskExectorExample中可以是单身：

And in your TaskExectorExample which can be the singleton:

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MesasgePrinterTask上使用@Configurable注释，这将依赖注入到MessagePrinterTask中，即使它是在Spring容器之外实例化的 - 虽然使用@Configurable（需要AspectJ）有一些捕获：

b. Using @Configurable annotation on your MesasgePrinterTask, this will inject in dependencies into MessagePrinterTask even though it is instantiated outside of a Spring Container - there are some catches in using @Configurable though(requires AspectJ):

@Configurable
class MessagePrinterTask implements Runnable {

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