通常我们使用新的Thread(….).start();但我想知道为什么我们不能使用@Async-Annotation.
这是代码：
package net.vectorpublish.desktop.vp;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import javax.annotation.postconstruct;
import javax.inject.Inject;
import javax.inject.Named;
import javax.swing.ImageIcon;
import javax.swing.SwingUtilities;
import org.springframework.scheduling.annotation.Async;
import net.vectorpublish.desktop.vp.api.history.Redo;
import net.vectorpublish.desktop.vp.api.layer.Layer;
import net.vectorpublish.desktop.vp.api.ui.Dialog;
import net.vectorpublish.desktop.vp.api.ui.KeyframeSlider;
import net.vectorpublish.desktop.vp.api.ui.ToolBar;
import net.vectorpublish.desktop.vp.api.ui.VPAbstractAction;
import net.vectorpublish.desktop.vp.api.vpd.DocumentNode;
import net.vectorpublish.desktop.vp.api.vpd.VectorPublishNode;
import net.vectorpublish.desktop.vp.gantt.AddTaskData;
import net.vectorpublish.desktop.vp.gantt.AddTaskHistoryStep;
import net.vectorpublish.desktop.vp.gantt.Priority;
import net.vectorpublish.desktop.vp.utils.SetUtils;
import net.vectorpublish.destkop.vp.gantt.rule.VetoableTaskAdder;
@SuppressWarnings("restriction")
@Named
public class AddTask extends VPAbstractAction implements Nodeselectionchangelistener {
public AddTask() {
super(GanttText.ADD_TASK,GanttText.ADD_TASK_TT,false);
}
@Inject
private final Dialog dlg = null;
@Inject
private final History hist = null;
@Inject
private final Redo redo = null;
@Inject
private final Layer layer = null;
@Inject
private final ToolBar toolbar = null;
@Inject
private final KeyframeSlider slider = null;
@Inject
private final SetetoableTaskAdder> council = null;
private DocumentNode doc;
@Async // <----------------------------------------------- This creates the Exception!
public void actionPerformed(ActionEvent arg0) {
try {
VectorPublishNode selected = layer.getSelection().iterator().next();
FutureetoImmutableIndex(selected),slider.getTime(),points.get(),username.get(),load(avatar.get()));
AddTaskHistoryStep data = new AddTaskHistoryStep(hist,addTaskData);
redo.actionPerformed(arg0);
} catch (InterruptedException e) {
e.printstacktrace();
} catch (ExecutionException e) {
e.printstacktrace();
} catch (MalformedURLException e) {
e.printstacktrace();
}
}
private BufferedImage load(String string) throws MalformedURLException {
ImageIcon ii = new ImageIcon(new URL(string));
return (BufferedImage) ii.getimage();
}
public void changednodeselection() {
Seteto = false;
for (VetoableTaskAdder vetoableTaskAdder : council) {
veto &= vetoableTaskAdder.hasVeto(nodes);
}
setEnabled(!veto);
}
}
@postconstruct
public void setup() {
toolbar.add(this);
}
}
这是例外：
DefaultI8nImageFactory Found: Image for key net.vectorpublish:io/new/large in cache! (DefaultI8nImageFactory > NewFile)
DefaultI8nImageFactory Found: Image for key net.vectorpublish:io/open/small in cache! (DefaultI8nImageFactory > OpenImpl)
DefaultI8nImageFactory Found: Image for key net.vectorpublish:io/open/large in cache! (DefaultI8nImageFactory > OpenImpl)
Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'addTask': Bean with name 'addTask' has been injected into other beans [nodeselectionChangeImpl,translation] in its raw version as part of a circular reference,but has eventually been wrapped. This means that said other beans do not use the final version of the bean. This is often the result of over-eager type matching - consider using 'getBeanNamesOfType' with the 'allowEagerInit' flag turned off,for example.
org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'addTask': Bean with name 'addTask' has been injected into other beans [nodeselectionChangeImpl,for example.
at org.springframework.beans.factory.support.AbstractAutowireCapablebeanfactory.doCreateBean(AbstractAutowireCapablebeanfactory.java:583)
at org.springframework.beans.factory.support.AbstractAutowireCapablebeanfactory.createBean(AbstractAutowireCapablebeanfactory.java:482)
at org.springframework.beans.factory.support.Abstractbeanfactory$1.getobject(Abstractbeanfactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.Abstractbeanfactory.doGetBean(Abstractbeanfactory.java:302)
at org.springframework.beans.factory.support.Abstractbeanfactory.getBean(Abstractbeanfactory.java:197)
at org.springframework.beans.factory.support.DefaultListablebeanfactory.preInstantiateSingletons(DefaultListablebeanfactory.java:754)
at org.springframework.context.support.AbstractApplicationContext.finishbeanfactoryInitialization(AbstractApplicationContext.java:866)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542)
at org.springframework.context.annotation.AnnotationConfigApplicationContext.figApplicationContext.java:84)
at net.vectorpublish.desktop.vp.VectorPublishApplicationContext.java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:282)
at java.lang.Thread.run(Thread.java:745)
编辑
由于一些更高的决定,我必须尊重：
最佳答案
在这种情况下,BeanCurrentlyInCreationException的根本原因是由于在最终字段上使用了@Inject(或其Spring的等效@Autowired).
要了解应该考虑bean生命周期的行为.
> Spring首先构造对象,其字段具有默认值,即null.
>构造对象后,Spring使用反射来注入,即初始化字段的实际值
因此,第二步与字段的最终声明相矛盾,这些字段规定该字段可以具有一个且仅有一个值,该值应该在构造时分配.
因此,为了解决这个问题,要么从字段中删除最终声明,要么使用构造函数注入(考虑到依赖项的数量,前者在这种特殊情况下是可取的)
如果需要更多信息,请在评论中告知.
希望这可以帮助！
P.S.：虽然我在任何官方文档中都找不到这种行为的明确提及但是here在实例中巧妙地解释了其中该字段仅在构造符注入的情况下被标记为final.
编辑： –
引入@Async强制Spring来创建和使用bean proxies,如果存在循环引用,则会导致BeanCurrentlyInCreationException.
这是因为Spring最初注入bean的原始版本并尝试将方面应用于它并失败,因为默认情况下RawInjectionDespiteWrapping被禁用,如Nicolas Labrot所指出的.
要克服这一点
>打破循环参考(尽管建议,但需要重新设计,因此需要付出很多努力)
>使用延迟初始化(如下所述)
懒豆初始化
如果使用xml配置,则在root元素中提供default-lazy-init =“true”,如下所示
spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
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