Bean 引用

如果評估上下文已配置 Bean 解析器，則可以使用 @ 符號作為字首從表示式中查詢 Bean。以下示例展示瞭如何實現這一點

  • Java

  • Kotlin

ExpressionParser parser = new SpelExpressionParser();
StandardEvaluationContext context = new StandardEvaluationContext();
context.setBeanResolver(new MyBeanResolver());

// This will end up calling resolve(context, "someBean") on MyBeanResolver
// during evaluation.
Object bean = parser.parseExpression("@someBean").getValue(context);
val parser = SpelExpressionParser()
val context = StandardEvaluationContext()
context.setBeanResolver(MyBeanResolver())

// This will end up calling resolve(context, "someBean") on MyBeanResolver
// during evaluation.
val bean = parser.parseExpression("@someBean").getValue(context)

如果 Bean 名稱包含點 (.) 或其他特殊字元，則必須將 Bean 名稱作為字串字面值提供，例如 @'order.service'。

要訪問工廠 Bean 本身，則應改為在 Bean 名稱前加上 & 符號。以下示例展示瞭如何實現這一點

  • Java

  • Kotlin

ExpressionParser parser = new SpelExpressionParser();
StandardEvaluationContext context = new StandardEvaluationContext();
context.setBeanResolver(new MyBeanResolver());

// This will end up calling resolve(context, "&someFactoryBean") on
// MyBeanResolver during evaluation.
Object factoryBean = parser.parseExpression("&someFactoryBean").getValue(context);
val parser = SpelExpressionParser()
val context = StandardEvaluationContext()
context.setBeanResolver(MyBeanResolver())

// This will end up calling resolve(context, "&someFactoryBean") on
// MyBeanResolver during evaluation.
val factoryBean = parser.parseExpression("&someFactoryBean").getValue(context)