org.springframework.core.Ordered接口

最新推荐文章于 2025-05-07 19:07:37 发布

最新推荐文章于 2025-05-07 19:07:37 发布 · 864 阅读

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#java

本文探讨了Ordered接口的用途及实现方式，解释了如何通过优先级设置影响类的加载顺序，以PropertyPlaceholderConfigurer为例进行深入解读。

关于Ordered接口，用过的人可能知道，这里我谈下自己的理解。也希望各位大神能给予指点。

源码如下：

/**
* Interface that can be implemented by objects that should be
* orderable, for example in a Collection.
*
* <p>The actual order can be interpreted as prioritization, with
* the first object (with the lowest order value) having the highest
* priority.
*
* <p>Note that there is a 'priority' marker for this interface:
* {@link PriorityOrdered}. Order values expressed by PriorityOrdered
* objects always apply before order values of 'plain' Ordered values.
*
* @author Juergen Hoeller
* @since 07.04.2003
* @see OrderComparator
* @see org.springframework.core.annotation.Order
*/

public interface Ordered {

/**
* Useful constant for the highest precedence value.
* @see java.lang.Integer#MIN_VALUE
*/
int HIGHEST_PRECEDENCE = Integer.MIN_VALUE;

/**
* Useful constant for the lowest precedence value.
* @see java.lang.Integer#MAX_VALUE
*/
int LOWEST_PRECEDENCE = Integer.MAX_VALUE;

/**
* Return the order value of this object, with a
* higher value meaning greater in terms of sorting.
* <p>Normally starting with 0, with <code>Integer.MAX_VALUE</code>
* indicating the greatest value. Same order values will result
* in arbitrary positions for the affected objects.
* <p>Higher values can be interpreted as lower priority. As a
* consequence, the object with the lowest value has highest priority
* (somewhat analogous to Servlet "load-on-startup" values).
* @return the order value
*/
int getOrder();

}