java 延迟任务：Spring 3 中的调度器第一次执行
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Delay task:scheduler first execution in Spring 3
提问by Gerco Dries
I have a simple application that uses Spring 3 for dependency injection. I have a JFrame for the user to look at and some background tasks for synchronizing with a back-end server and local database maintenance.
我有一个简单的应用程序，它使用 Spring 3 进行依赖注入。我有一个 JFrame 供用户查看，还有一些后台任务用于与后端服务器和本地数据库维护同步。
This is the relevant part of my application context:
这是我的应用程序上下文的相关部分：
<task:scheduler id="scheduler" pool-size="1"/>
<task:scheduled-tasks scheduler="scheduler">
<task:scheduled ref="synchronizer" method="incrementalSync" fixed-delay="600000"/>
... more tasks ...
</task:scheduled-tasks>
<bean id="mainFrame" class="nl.gdries.myapp.client.ui.MainFrame">
... properties and such ...
</bean>
When I start this applicationContext the scheduler immediately starts executing the background tasks even while my UI is loading. Because the first task is a rather heavy one at the start I want it to wait for the UI to fully load and display before it starts execution.
当我启动这个 applicationContext 时，即使我的 UI 正在加载，调度程序也会立即开始执行后台任务。因为第一个任务在开始时相当繁重，我希望它在开始执行之前等待 UI 完全加载和显示。
Does anyone know how to tell Spring to delay executing the scheduled tasks until a moment of my choosing?
有谁知道如何告诉 Spring 将计划任务的执行延迟到我选择的某个时刻？
采纳答案by skaffman
This seems to have been left out of the <task:scheduled>bean definition, something I only just noticed last week.
这似乎已被排除在<task:scheduled>bean 定义之外，这是我上周才注意到的。
Remember, though, that the <task:...>definitions are just shortcuts, you can always use the explicit approach, by defining a ScheduledExecutorFactoryBean, with nested ScheduledExecutorTaskbeans. This gives you much finer control, including initialDelay.
但是请记住，<task:...>定义只是快捷方式，您始终可以使用显式方法，通过ScheduledExecutorFactoryBean使用嵌套ScheduledExecutorTaskbean定义 a 。这为您提供了更精细的控制，包括initialDelay.
回答by inv
I've had the same problem and came back to TimerTask as it is in 25.7.1 point in http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/scheduling.html
我遇到了同样的问题，回到了 TimerTask，因为它在http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/scheduling.html中的 25.7.1 点
<bean id="scheduledTask" class="org.springframework.scheduling.timer.ScheduledTimerTask">
<!-- wait 25 seconds before starting repeated execution -->
<property name="delay" value="25000" />
<!-- run every 50 seconds -->
<property name="period" value="50000" />
<property name="timerTask" ref="task" />
</bean>
<bean id="timerFactory" class="org.springframework.scheduling.timer.TimerFactoryBean">
<property name="scheduledTimerTasks">
<list>
<ref bean="scheduledTask" />
</list>
</property>
</bean>
I hope in Spring 3.1 will be initialDelay attribute in <task:scheduled>, since in Spring 3.0 TimerFactoryBean is Deprecated.
You can vote for this issue: jira.springframework.org/browse/SPR-7022
我希望在 Spring 3.1 中将是 initialDelay 属性<task:scheduled>，因为在 Spring 3.0 TimerFactoryBean 中已弃用。您可以为此问题投票：jira.springframework.org/browse/SPR-7022
回答by Liv
This has been introduced by the way in spring 3.2so if you use the 3.2 schema it's available again -- e.g.:
这已在spring 3.2 中引入，因此如果您使用 3.2 模式，它再次可用 - 例如：
<?xml version="1.0"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:task="http://www.springframework.org/schema/task"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.2.xsd">
....
....
the above allows you to do this:
以上允许你这样做：
<task:scheduler id="scheduler" pool-size="1"/>
<task:scheduled-tasks scheduler="scheduler">
<task:scheduled ref="synchronizer" method="incrementalSync" fixed-delay="600000" initial-delay="initial delay needed for the app to start"/>
... more tasks ...
</task:scheduled-tasks>
