One asyncannotationbeanpostprocessor may exist within the context.

I had this problem when I copied applicationContext.xml and created new one called applicationContextAdditional.xml. I did n‘t try to find the reason, but both contained namespace

<bean ...
    xmlns: task = "http://www.springframework.org/schema/task"
    ...
    xsi: schemaLocation = "
   http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.0.xsd ">

    ...

</ bean>
when I removed the namespace from the second one my problem was solved. Maybe it helps someone.

I have faced this once after implementing our own AsyncTaskExecutor andforgetting to remove default <task:
 annotation-driven />

Check if you have something like this, if yes remove one of the task.

<task: annotation-driven executor = "customAsyncTaskExecutor" scheduler = "taskScheduler" />
<task: annotation-driven />
<task: annotation-driven> appears twice.

This happens when spring parses the <task: annotation-driven /> text twice in a config XML.
For me this was happening because both applicationContext-root.xml and applicationContext-where-annotation-driven-is-specififed.xml were imported in my WEB.xml in <context-param> section.

Leaving only applicationContext-root.xml in WEB.xml solved the issue.
<task: annotation-driven /> appears twice.
Only one AsyncAnnotationBeanPostProcessor may exist within the context.

label:

Original address: http://blog.csdn.net/liyanlei5858/article/details/51361268