org.springframework.core.io

## 类 FileSystemResource

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

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

      public class FileSystemResource
      extends AbstractResource
      implements WritableResource

  `Resource` implementation for `java.io.File` handles. Supports resolution as a `File` and also as a `URL`. Implements the extended `WritableResource` interface.

  Note: As of Spring Framework 5.0, this `Resource` implementation uses NIO.2 API for read/write interactions. Nevertheless, in contrast to `PathResource`, it primarily manages a `java.io.File` handle.

  从以下版本开始:
    28.12.2003
  作者:
    Juergen Hoeller
  另请参阅:
    `PathResource`, `File`, `Files`

- - ### 构造器概要

    构造器
    构造器和说明
    `FileSystemResource(File file)` Create a new `FileSystemResource` from a `File` handle.
    `FileSystemResource(String path)` Create a new `FileSystemResource` from a file path.

  - ### 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
    --- | ---
    `long` | `contentLength()` This implementation returns the underlying File's length.
    `Resource` | `createRelative(String relativePath)` This implementation creates a FileSystemResource, applying the given path relative to the path of the underlying file of this resource descriptor.
    `boolean` | `equals(Object other)` This implementation compares the underlying File references.
    `boolean` | `exists()` This implementation returns whether the underlying file exists.
    `String` | `getDescription()` This implementation returns a description that includes the absolute path of the file.
    `File` | `getFile()` This implementation returns the underlying File reference.
    `String` | `getFilename()` This implementation returns the name of the file.
    `InputStream` | `getInputStream()` This implementation opens a NIO file stream for the underlying file.
    `OutputStream` | `getOutputStream()` This implementation opens a FileOutputStream for the underlying file.
    `String` | `getPath()` Return the file path for this resource.
    `URI` | `getURI()` This implementation returns a URI for the underlying file.
    `URL` | `getURL()` This implementation returns a URL for the underlying file.
    `int` | `hashCode()` This implementation returns the hash code of the underlying File reference.
    `boolean` | `isFile()` This implementation always indicates a file.
    `boolean` | `isReadable()` This implementation checks whether the underlying file is marked as readable (and corresponds to an actual file with content, not to a directory).
    `boolean` | `isWritable()` This implementation checks whether the underlying file is marked as writable (and corresponds to an actual file with content, not to a directory).
    `ReadableByteChannel` | `readableChannel()` This implementation opens a FileChannel for the underlying file.
    `WritableByteChannel` | `writableChannel()` This implementation opens a FileChannel for the underlying file.

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

      `getFileForLastModifiedCheck, isOpen, lastModified, toString`

    - ### 从类继承的方法 java.lang.Object

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

    - ### 从接口继承的方法 org.springframework.core.io.Resource

      `isOpen, lastModified`

- - ### 构造器详细资料

    - #### FileSystemResource

          public FileSystemResource(File file)

      Create a new `FileSystemResource` from a `File` handle.

      Note: When building relative resources via `createRelative(java.lang.String)`, the relative path will apply at the same directory level: e.g. new File("C:/dir1"), relative path "dir2" -> "C:/dir2"! If you prefer to have relative paths built underneath the given root directory, use the `constructor with a file path` to append a trailing slash to the root path: "C:/dir1/", which indicates this directory as root for all relative paths.

      参数:
        `file` - a File handle

    - #### FileSystemResource

          public FileSystemResource(String path)

      Create a new `FileSystemResource` from a file path.

      Note: When building relative resources via `createRelative(java.lang.String)`, it makes a difference whether the specified resource base path here ends with a slash or not. In the case of "C:/dir1/", relative paths will be built underneath that root: e.g. relative path "dir2" -> "C:/dir1/dir2". In the case of "C:/dir1", relative paths will apply at the same directory level: relative path "dir2" -> "C:/dir2".

      参数:
        `path` - a file path

  - ### 方法详细资料

    - #### getPath

          public final String getPath()

      Return the file path for this resource.

    - #### exists

          public boolean exists()

      This implementation returns whether the underlying file exists.
      指定者:
        `exists` 在接口中 `Resource`
      覆盖:
        `exists` 在类中 `AbstractResource`
      另请参阅:
        `File.exists()`

    - #### isReadable

          public boolean isReadable()

      This implementation checks whether the underlying file is marked as readable (and corresponds to an actual file with content, not to a directory).
      指定者:
        `isReadable` 在接口中 `Resource`
      覆盖:
        `isReadable` 在类中 `AbstractResource`
      另请参阅:
        `File.canRead()`, `File.isDirectory()`

    - #### getInputStream

          public InputStream getInputStream()
                                     throws IOException

      This implementation opens a NIO file stream for the underlying file.
      指定者:
        `getInputStream` 在接口中 `InputStreamSource`
      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
      另请参阅:
        `FileInputStream`

    - #### isWritable

          public boolean isWritable()

      This implementation checks whether the underlying file is marked as writable (and corresponds to an actual file with content, not to a directory).
      指定者:
        `isWritable` 在接口中 `WritableResource`
      另请参阅:
        `File.canWrite()`, `File.isDirectory()`

    - #### getOutputStream

          public OutputStream getOutputStream()
                                       throws IOException

      This implementation opens a FileOutputStream for the underlying file.
      指定者:
        `getOutputStream` 在接口中 `WritableResource`
      抛出:
        `IOException` - if the stream could not be opened
      另请参阅:
        `FileOutputStream`

    - #### getURL

          public URL getURL()
                     throws IOException

      This implementation returns a URL for the underlying file.
      指定者:
        `getURL` 在接口中 `Resource`
      覆盖:
        `getURL` 在类中 `AbstractResource`
      抛出:
        `IOException` - if the resource cannot be resolved as URL, i.e. if the resource is not available as descriptor
      另请参阅:
        `File.toURI()`

    - #### getURI

          public URI getURI()
                     throws IOException

      This implementation returns a URI for the underlying file.
      指定者:
        `getURI` 在接口中 `Resource`
      覆盖:
        `getURI` 在类中 `AbstractResource`
      抛出:
        `IOException` - if the resource cannot be resolved as URI, i.e. if the resource is not available as descriptor
      另请参阅:
        `File.toURI()`

    - #### isFile

          public boolean isFile()

      This implementation always indicates a file.
      指定者:
        `isFile` 在接口中 `Resource`
      覆盖:
        `isFile` 在类中 `AbstractResource`
      另请参阅:
        `Resource.getFile()`

    - #### getFile

          public File getFile()

      This implementation returns the underlying File reference.
      指定者:
        `getFile` 在接口中 `Resource`
      覆盖:
        `getFile` 在类中 `AbstractResource`
      另请参阅:
        `InputStreamSource.getInputStream()`

    - #### readableChannel

          public ReadableByteChannel readableChannel()
                                              throws IOException

      This implementation opens a FileChannel for the underlying file.
      指定者:
        `readableChannel` 在接口中 `Resource`
      覆盖:
        `readableChannel` 在类中 `AbstractResource`
      返回:
        the byte channel for the underlying resource (must not be `null`)
      抛出:
        `FileNotFoundException` - if the underlying resource doesn't exist
        `IOException` - if the content channel could not be opened
      另请参阅:
        `FileChannel`

    - #### writableChannel

          public WritableByteChannel writableChannel()
                                              throws IOException

      This implementation opens a FileChannel for the underlying file.
      指定者:
        `writableChannel` 在接口中 `WritableResource`
      返回:
        the byte channel for the underlying resource (must not be `null`)
      抛出:
        `FileNotFoundException` - if the underlying resource doesn't exist
        `IOException` - if the content channel could not be opened
      另请参阅:
        `FileChannel`

    - #### contentLength

          public long contentLength()
                             throws IOException

      This implementation returns the underlying File's length.
      指定者:
        `contentLength` 在接口中 `Resource`
      覆盖:
        `contentLength` 在类中 `AbstractResource`
      抛出:
        `IOException` - if the resource cannot be resolved (in the file system or as some other known physical resource type)
      另请参阅:
        `InputStreamSource.getInputStream()`

    - #### createRelative

          public Resource createRelative(String relativePath)

      This implementation creates a FileSystemResource, applying the given path relative to the path of the underlying file of this resource descriptor.
      指定者:
        `createRelative` 在接口中 `Resource`
      覆盖:
        `createRelative` 在类中 `AbstractResource`
      参数:
        `relativePath` - the relative path (relative to this resource)
      返回:
        the resource handle for the relative resource
      另请参阅:
        `StringUtils.applyRelativePath(String, String)`

    - #### getFilename

          public String getFilename()

      This implementation returns the name of the file.
      指定者:
        `getFilename` 在接口中 `Resource`
      覆盖:
        `getFilename` 在类中 `AbstractResource`
      另请参阅:
        `File.getName()`

    - #### getDescription

          public String getDescription()

      This implementation returns a description that includes the absolute path of the file.
      指定者:
        `getDescription` 在接口中 `Resource`
      另请参阅:
        `File.getAbsolutePath()`

    - #### equals

          public boolean equals(Object other)

      This implementation compares the underlying File references.
      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 File reference.
      覆盖:
        `hashCode` 在类中 `AbstractResource`
      另请参阅:
        `Resource.getDescription()`