FileDataSource (Java EE 5 SDK)

javax.activation Class FileDataSource

java.lang.Object
  javax.activation.FileDataSource

所有已实现的接口:

DataSource

public class FileDataSource

extends Object

implements DataSource

The FileDataSource class implements a simple DataSource object that encapsulates a file. It provides data typing services via a FileTypeMap object.

FileDataSource Typing Semantics

The FileDataSource class delegates data typing of files to an object subclassed from the FileTypeMap class. The setFileTypeMap method can be used to explicitly set the FileTypeMap for an instance of FileDataSource. If no FileTypeMap is set, the FileDataSource will call the FileTypeMap's getDefaultFileTypeMap method to get the System's default FileTypeMap.

另请参见:

DataSource, FileTypeMap, MimetypesFileTypeMap

FileDataSource

public FileDataSource(File file)

Creates a FileDataSource from a File object. Note: The file will not actually be opened until a method is called that requires the file to be opened.

参数:

file - the file

FileDataSource

public FileDataSource(String name)

Creates a FileDataSource from the specified path name. Note: The file will not actually be opened until a method is called that requires the file to be opened.

参数:

name - the system-dependent file name.

getInputStream

public InputStream getInputStream()
                           throws IOException

This method will return an InputStream representing the the data and will throw an IOException if it can not do so. This method will return a new instance of InputStream with each invocation.

规范说明:

getInputStream in interface DataSource

返回:

an InputStream

抛出异常:

IOException

getOutputStream

public OutputStream getOutputStream()
                             throws IOException

This method will return an OutputStream representing the the data and will throw an IOException if it can not do so. This method will return a new instance of OutputStream with each invocation.

规范说明:

getOutputStream in interface DataSource

返回:

an OutputStream

抛出异常:

IOException

getContentType

public String getContentType()

This method returns the MIME type of the data in the form of a string. This method uses the currently installed FileTypeMap. If there is no FileTypeMap explictly set, the FileDataSource will call the getDefaultFileTypeMap method on FileTypeMap to acquire a default FileTypeMap. Note: By default, the FileTypeMap used will be a MimetypesFileTypeMap.

规范说明:

getContentType in interface DataSource

返回:

the MIME Type

另请参见:

FileTypeMap.getDefaultFileTypeMap()

getName

public String getName()

Return the name of this object. The FileDataSource will return the file name of the object.

规范说明:

getName in interface DataSource

返回:

the name of the object.

另请参见:

DataSource

getFile

public File getFile()

Return the File object that corresponds to this FileDataSource.

返回:

the File object for the file represented by this object.

setFileTypeMap

public void setFileTypeMap(FileTypeMap map)

Set the FileTypeMap to use with this FileDataSource

参数:

map - The FileTypeMap for this object.

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