org.springframework.core.io

## 类 DescriptiveResource

- java.lang.Object
- - org.springframework.core.io.AbstractResource
  - - org.springframework.core.io.DescriptiveResource

- 所有已实现的接口:
    InputStreamSource, Resource

      public class DescriptiveResource
      extends AbstractResource

  Simple `Resource` implementation that holds a resource description but does not point to an actually readable resource.

  To be used as placeholder if a `Resource` argument is expected by an API but not necessarily used for actual reading.

  从以下版本开始:
    1.2.6
  作者:
    Juergen Hoeller

- - ### 构造器概要

    构造器
    构造器和说明
    `DescriptiveResource(String description)` Create a new DescriptiveResource.

  - ### 方法概要

    所有方法 实例方法 具体方法
    限定符和类型 | 方法和说明
    --- | ---
    `boolean` | `equals(Object other)` This implementation compares the underlying description String.
    `boolean` | `exists()` This implementation checks whether a File can be opened, falling back to whether an InputStream can be opened.
    `String` | `getDescription()` Return a description for this resource, to be used for error output when working with the resource.
    `InputStream` | `getInputStream()` Return an `InputStream` for the content of an underlying resource.
    `int` | `hashCode()` This implementation returns the hash code of the underlying description String.
    `boolean` | `isReadable()` This implementation always returns `true`.

    - ### 从类继承的方法 org.springframework.core.io.AbstractResource

      `contentLength, createRelative, getFile, getFileForLastModifiedCheck, getFilename, getURI, getURL, isFile, isOpen, lastModified, readableChannel, toString`

    - ### 从类继承的方法 java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### 构造器详细资料

    - #### DescriptiveResource

          public DescriptiveResource(@Nullable
                                     String description)

      Create a new DescriptiveResource.
      参数:
        `description` - the resource description

  - ### 方法详细资料

    - #### exists

          public boolean exists()

      从类复制的说明: `AbstractResource`
      This implementation checks whether a File can be opened, falling back to whether an InputStream can be opened. This will cover both directories and content resources.
      指定者:
        `exists` 在接口中 `Resource`
      覆盖:
        `exists` 在类中 `AbstractResource`

    - #### isReadable

          public boolean isReadable()

      从类复制的说明: `AbstractResource`
      This implementation always returns `true`.
      指定者:
        `isReadable` 在接口中 `Resource`
      覆盖:
        `isReadable` 在类中 `AbstractResource`
      另请参阅:
        `InputStreamSource.getInputStream()`

    - #### getInputStream

          public InputStream getInputStream()
                                     throws IOException

      从接口复制的说明: `InputStreamSource`
      Return an `InputStream` for the content of an underlying resource.

      It is expected that each call creates a fresh stream.

      This requirement is particularly important when you consider an API such as JavaMail, which needs to be able to read the stream multiple times when creating mail attachments. For such a use case, it is required that each `getInputStream()` call returns a fresh stream.

      返回:
        the input stream for the underlying resource (must not be `null`)
      抛出:
        `FileNotFoundException` - if the underlying resource doesn't exist
        `IOException` - if the content stream could not be opened

    - #### getDescription

          public String getDescription()

      从接口复制的说明: `Resource`
      Return a description for this resource, to be used for error output when working with the resource.

      Implementations are also encouraged to return this value from their `toString` method.

      另请参阅:
        `Object.toString()`

    - #### equals

          public boolean equals(Object other)

      This implementation compares the underlying description String.
      覆盖:
        `equals` 在类中 `AbstractResource`
      另请参阅:
        `Resource.getDescription()`

    - #### hashCode

          public int hashCode()

      This implementation returns the hash code of the underlying description String.
      覆盖:
        `hashCode` 在类中 `AbstractResource`
      另请参阅:
        `Resource.getDescription()`