FileDataSource (Java EE 5)

java.lang.Object
  javax.activation.FileDataSource

FileDataSource 类实现一个封装文件的简单 DataSource 对象。它通过 FileTypeMap 对象提供数据分类服务。

FileDataSource 分类语义

FileDataSource 类将文件的数据分类委托给一个从 FileTypeMap 类子类化的对象。setFileTypeMap 方法可用于为 FileDataSource 实例显示地设置 FileTypeMap。如果没有设置任何 FileTypeMap，则 FileDataSource 将调用 FileTypeMap 的 getDefaultFileTypeMap 方法获取系统的默认 FileTypeMap。

See also

javax.activation.DataSource, javax.activation.FileTypeMap, javax.activation.MimetypesFileTypeMap

英文文档：

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.

See Also:

DataSource, FileTypeMap, MimetypesFileTypeMap

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Constructor Summary
FileDataSource(File file)           Creates a FileDataSource from a File object.
FileDataSource(String name)           Creates a FileDataSource from the specified path name.

 

Method Summary
String	getContentType()           This method returns the MIME type of the data in the form of a string.
File	getFile()           Return the File object that corresponds to this FileDataSource.
InputStream	getInputStream()           This method will return an InputStream representing the the data and will throw an IOException if it can not do so.
String	getName()           Return the name of this object.
OutputStream	getOutputStream()           This method will return an OutputStream representing the the data and will throw an IOException if it can not do so.
void	setFileTypeMap(FileTypeMap map)           Set the FileTypeMap to use with this FileDataSource

 

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Constructor Detail

public FileDataSource(java.io.File file)
根据 File 对象创建 FileDataSource。注：在调用要求文件打开的方法之前，文件实际上不会打开。

file

文件

英文文档：

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.

Parameters:

file - the file

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public FileDataSource(String name)
根据指定的路径名创建 FileDataSource。注：在调用要求文件打开的方法之前，文件实际上不会打开。

name	取决于系统的文件名。

英文文档：

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.

Parameters:

name - the system-dependent file name.

Method Detail

public java.io.InputStream getInputStream() throws java.io.IOException
此方法将返回一个表示数据的 InputStream；如果不能返回，则抛出 IOException。每次调用此方法都会返回一个新的 InputStream 实例。

return

InputStream

英文文档：

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.

Specified by:

getInputStream in interface DataSource

Returns:

an InputStream

Throws:

IOException

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public java.io.OutputStream getOutputStream() throws java.io.IOException
此方法将返回一个表示数据的 OutputStream；如果不能返回，则抛出 IOException。每次调用此方法都会返回一个新的 OutputStream 实例。

return

OutputStream

英文文档：

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.

Specified by:

getOutputStream in interface DataSource

Returns:

an OutputStream

Throws:

IOException

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public String getContentType()
此方法以字符串形式返回数据的 MIME 类型。此方法使用当前安装的 FileTypeMap。如果没有显示地设置任何 FileTypeMap，FileDataSource 将对 FileTypeMap 调用 getDefaultFileTypeMap 方法获取默认的 FileTypeMap。注：默认情况下，使用的 FileTypeMap 是 MimetypesFileTypeMap。

return	MIME 类型
See also	getDefaultFileTypeMap

英文文档：

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.

Specified by:

getContentType in interface DataSource

Returns:

the MIME Type

See Also:

FileTypeMap.getDefaultFileTypeMap()

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public String getName()
返回此对象的名称。FileDataSource 将返回对象的文件名。

return	对象的名称。
See also	javax.activation.DataSource

英文文档：

getName

public String getName()

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

Specified by:

getName in interface DataSource

Returns:

the name of the object.

See Also:

DataSource

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public java.io.File getFile()
返回与此 FileDataSource 对应的 File 对象。

return

此对象表示的文件的 File 对象。

英文文档：

getFile

public File getFile()

Return the File object that corresponds to this FileDataSource.

Returns:

the File object for the file represented by this object.

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public void setFileTypeMap(FileTypeMap map)
设置用于此 FileDataSource 的 FileTypeMap。

map	此对象的 FileTypeMap。

英文文档：

setFileTypeMap

public void setFileTypeMap(FileTypeMap map)

Set the FileTypeMap to use with this FileDataSource

Parameters:

map - The FileTypeMap for this object.

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