提交 ea3250c8 编写于 作者: J Juergen Hoeller

Explicit notes on class/method-level semantics in class hierarchies

Issue: SPR-17445
上级 b1f5f515
......@@ -27,7 +27,12 @@ import org.springframework.core.annotation.AliasFor;
import org.springframework.transaction.TransactionDefinition;
/**
* Describes transaction attributes on a method or class.
* Describes a transaction attribute on an individual method or on a class.
*
* <p>At the class level, this annotation applies as a default to all methods of
* the declaring class and its subclasses. Note that it does not apply to ancestor
* classes up the class hierarchy; methods need to be locally redeclared in order
* to participate in a subclass-level annotation.
*
* <p>This annotation type is generally directly comparable to Spring's
* {@link org.springframework.transaction.interceptor.RuleBasedTransactionAttribute}
......
......@@ -1100,8 +1100,19 @@ Consider the following class definition:
----
====
When the preceding POJO is defined as a bean in a Spring IoC container, you can make the bean instance
transactional by adding only one line of XML configuration:
Used at the class level as above, the annotation indicates a default for all methods
of the declaring class (as well as its subclasses). Alternatively, each method can
get annotated individually. Note that a class-level annotation does not apply to
ancestor classes up the class hierarchy; in such a scenario, methods need to be
locally redeclared in order to participate in a subclass-level annotation.
When a POJO class such as the one above is defined as a bean in a Spring context,
you can make the bean instance transactional through an `@EnableTransactionManagement`
annotation in a `@Configuration` class. See the
{api-spring-framework}/transaction/annotation/EnableTransactionManagement.html[javadoc]
for full details.
In XML configuration, the `<tx:annotation-driven/>` tag provides similar convenience:
====
[source,xml,indent=0]
......@@ -1126,6 +1137,7 @@ transactional by adding only one line of XML configuration:
<!-- enable the configuration of transactional behavior based on annotations -->
<tx:annotation-driven transaction-manager="txManager"/><!-- a PlatformTransactionManager is still required --> <1>
<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<!-- (this dependency is defined somewhere else) -->
<property name="dataSource" ref="dataSource"/>
......@@ -1144,11 +1156,6 @@ if the bean name of the `PlatformTransactionManager` that you want to wire in ha
dependency-inject has any other name, you have to use the `transaction-manager` attribute,
as in the preceding example.
NOTE: If you use Java-based configuration, the `@EnableTransactionManagement` annotation
provides equivalent support . You can add the annotation to a `@Configuration` class.
See the {api-spring-framework}/transaction/annotation/EnableTransactionManagement.html[javadoc]
for full details.
.Method visibility and `@Transactional`
****
When you use proxies, you should apply the `@Transactional` annotation only to methods
......@@ -1158,13 +1165,13 @@ method does not exhibit the configured transactional settings. If you need to an
non-public methods, consider using AspectJ (described later).
****
You can place the `@Transactional` annotation before an interface definition, a method
You can apply the `@Transactional` annotation to an interface definition, a method
on an interface, a class definition, or a public method on a class. However, the
mere presence of the `@Transactional` annotation is not enough to activate the
transactional behavior. The `@Transactional` annotation is merely metadata that can be
consumed by some runtime infrastructure that is `@Transactional`-aware and that can use
the metadata to configure the appropriate beans with transactional behavior. In the
preceding example, the `<tx:annotation-driven/>` element switches on the
transactional behavior. The `@Transactional` annotation is merely metadata that can
be consumed by some runtime infrastructure that is `@Transactional`-aware and that
can use the metadata to configure the appropriate beans with transactional behavior.
In the preceding example, the `<tx:annotation-driven/>` element switches on the
transactional behavior.
TIP: The Spring team recommends that you annotate only concrete classes (and methods of
......@@ -1173,9 +1180,8 @@ You certainly can place the `@Transactional` annotation on an interface (or an i
method), but this works only as you would expect it to if you use interface-based
proxies. The fact that Java annotations are not inherited from interfaces means that,
if you use class-based proxies (`proxy-target-class="true"`) or the weaving-based
aspect (`mode="aspectj"`), the transaction settings are not recognized by the
proxying and weaving infrastructure, and the object is not wrapped in a
transactional proxy, which would be decidedly bad.
aspect (`mode="aspectj"`), the transaction settings are not recognized by the proxying
and weaving infrastructure, and the object is not wrapped in a transactional proxy.
NOTE: In proxy mode (which is the default), only external method calls coming in through
the proxy are intercepted. This means that self-invocation (in effect, a method within
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册