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For the latest stable version, please use Spring Framework 6.2.0! |
Using depends-on
If a bean is a dependency of another bean, that usually means that one bean is set as a
property of another. Typically you accomplish this with the
<ref/> element>
in XML-based metadata or through autowiring.
However, sometimes dependencies between beans are less direct. An example is when a static
initializer in a class needs to be triggered, such as for database driver registration.
The depends-on attribute or @DependsOn annotation can explicitly force one or more beans
to be initialized before the bean using this element is initialized. The following example
uses the depends-on attribute to express a dependency on a single bean:
<bean id="beanOne" class="ExampleBean" depends-on="manager"/>
<bean id="manager" class="ManagerBean" />To express a dependency on multiple beans, supply a list of bean names as the value of
the depends-on attribute (commas, whitespace, and semicolons are valid
delimiters):
<bean id="beanOne" class="ExampleBean" depends-on="manager,accountDao">
<property name="manager" ref="manager" />
</bean>
<bean id="manager" class="ManagerBean" />
<bean id="accountDao" class="x.y.jdbc.JdbcAccountDao" />
The depends-on attribute can specify both an initialization-time dependency and,
in the case of singleton
beans only, a corresponding destruction-time dependency. Dependent beans that define a
depends-on relationship with a given bean are destroyed first, prior to the given bean
itself being destroyed. Thus, depends-on can also control shutdown order.
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