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Improve document for SpEL Bean References

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Sam Brannen 2024-08-10 16:44:17 +03:00
parent eab96073da
commit 4f607b59a3
1 changed files with 22 additions and 14 deletions
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36
framework-docs/modules/ROOT/pages/core/expressions/language-ref/bean-references.adoc
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@ -1,8 +1,8 @@
[[expressions-bean-references]]
= Bean References
If the evaluation context has been configured with a bean resolver, you can
look up beans from an expression by using the `@` symbol. The following example shows how
If the evaluation context has been configured with a bean resolver, you can look up beans
from an expression by using the `@` symbol as a prefix. The following example shows how
to do so:
[tabs]
@ -15,8 +15,9 @@ Java::
StandardEvaluationContext context = new StandardEvaluationContext();
context.setBeanResolver(new MyBeanResolver());
// This will end up calling resolve(context,"something") on MyBeanResolver during evaluation
Object bean = parser.parseExpression("@something").getValue(context);
// This will end up calling resolve(context, "someBean") on MyBeanResolver
// during evaluation.
Object bean = parser.parseExpression("@someBean").getValue(context);
----
Kotlin::
@ -27,13 +28,20 @@ Kotlin::
val context = StandardEvaluationContext()
context.setBeanResolver(MyBeanResolver())
// This will end up calling resolve(context,"something") on MyBeanResolver during evaluation
val bean = parser.parseExpression("@something").getValue(context)
// This will end up calling resolve(context, "someBean") on MyBeanResolver
// during evaluation.
val bean = parser.parseExpression("@someBean").getValue(context)
----
======
To access a factory bean itself, you should instead prefix the bean name with an `&` symbol.
The following example shows how to do so:
[NOTE]
====
If a bean name contains a dot (`.`) or other special characters, you must provide the
name of the bean as a _string literal_ – for example, `@'order.service'`.
====
To access a factory bean itself, you should instead prefix the bean name with an `&`
symbol. The following example shows how to do so:
[tabs]
======
@ -45,8 +53,9 @@ Java::
StandardEvaluationContext context = new StandardEvaluationContext();
context.setBeanResolver(new MyBeanResolver());
// This will end up calling resolve(context,"&foo") on MyBeanResolver during evaluation
Object bean = parser.parseExpression("&foo").getValue(context);
// This will end up calling resolve(context, "&someFactoryBean") on
// MyBeanResolver during evaluation.
Object factoryBean = parser.parseExpression("&someFactoryBean").getValue(context);
----
Kotlin::
@ -57,9 +66,8 @@ Kotlin::
val context = StandardEvaluationContext()
context.setBeanResolver(MyBeanResolver())
// This will end up calling resolve(context,"&foo") on MyBeanResolver during evaluation
val bean = parser.parseExpression("&foo").getValue(context)
// This will end up calling resolve(context, "&someFactoryBean") on
// MyBeanResolver during evaluation.
val factoryBean = parser.parseExpression("&someFactoryBean").getValue(context)
----
======