org.springframework.util

## 接口 PropertyPlaceholderHelper.PlaceholderResolver

- 封闭类:
    PropertyPlaceholderHelper
  函数接口:
    这是一个函数接口, 因此可用作 lambda 表达式或方法引用的赋值目标。

      @FunctionalInterface
      public static interface PropertyPlaceholderHelper.PlaceholderResolver

  Strategy interface used to resolve replacement values for placeholders contained in Strings.

- - ### 方法概要

    所有方法 实例方法 抽象方法
    限定符和类型 | 方法和说明
    --- | ---
    `String` | `resolvePlaceholder(String placeholderName)` Resolve the supplied placeholder name to the replacement value.

- - ### 方法详细资料

    - #### resolvePlaceholder

          @Nullable
          String resolvePlaceholder(String placeholderName)

      Resolve the supplied placeholder name to the replacement value.
      参数:
        `placeholderName` - the name of the placeholder to resolve
      返回:
        the replacement value, or `null` if no replacement is to be made