Java javax.imageio.stream Class FileImageInputStream（JDK8）

142 阅读 0 评论 0 点赞

Skip navigation links

Java™ Platform
Standard Ed. 8

All Classes

Summary:
Nested |
Field |
Constr |
Method

Detail:
Field |
Constr |
Method

java.lang.Object
- javax.imageio.stream.ImageInputStreamImpl
- - javax.imageio.stream.FileImageInputStream

All Implemented Interfaces:

Closeable, DataInput, AutoCloseable, ImageInputStream
```
public class FileImageInputStream
extends ImageInputStreamImpl
```
An implementation of ImageInputStream that gets its input from a File or RandomAccessFile. The file contents are assumed to be stable during the lifetime of the object.

Field Summary
- Fields inherited from class javax.imageio.stream.ImageInputStreamImpl
  bitOffset, byteOrder, flushedPos, streamPos

Constructor Summary

Constructors
Constructor and Description
`FileImageInputStream(File f)` Constructs a `FileImageInputStream` that will read from a given `File`.
`FileImageInputStream(RandomAccessFile raf)` Constructs a `FileImageInputStream` that will read from a given `RandomAccessFile`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` Closes the stream.
`protected void`	`finalize()` Finalizes this object prior to garbage collection.
`long`	`length()` Returns the length of the underlying file, or `-1` if it is unknown.
`int`	`read()` Reads a single byte from the stream and returns it as an `int` between 0 and 255.
`int`	`read(byte[] b, int off, int len)` Reads up to `len` bytes from the stream, and stores them into `b` starting at index `off`.
`void`	`seek(long pos)` Sets the current stream position to the desired location.

Methods inherited from class javax.imageio.stream.ImageInputStreamImpl
checkClosed, flush, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, isCached, isCachedFile, isCachedMemory, mark, read, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, reset, setBitOffset, setByteOrder, skipBytes, skipBytes

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

- Constructor Detail
  - FileImageInputStream
```
public FileImageInputStream(File f)
                     throws FileNotFoundException,
                            IOException
```
    Constructs a FileImageInputStream that will read from a given File.
    The file contents must not change between the time this object is constructed and the time of the last call to a read method.
    
    Parameters:
    
    f - a File to read from.
    
    Throws:
    
    IllegalArgumentException - if f is null.
    
    SecurityException - if a security manager exists and does not allow read access to the file.
    
    FileNotFoundException - if f is a directory or cannot be opened for reading for any other reason.
    
    IOException - if an I/O error occurs.
  - FileImageInputStream
```
public FileImageInputStream(RandomAccessFile raf)
```
    Constructs a FileImageInputStream that will read from a given RandomAccessFile.
    The file contents must not change between the time this object is constructed and the time of the last call to a read method.
    
    Parameters:
    
    raf - a RandomAccessFile to read from.
    
    Throws:
    
    IllegalArgumentException - if raf is null.
- Method Detail
  - read
```
public int read()
         throws IOException
```
    Description copied from class: ImageInputStreamImpl
    
    Reads a single byte from the stream and returns it as an int between 0 and 255. If EOF is reached, -1 is returned.
    Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.
    
    The bit offset within the stream must be reset to zero before the read occurs.
    
    Specified by:
    
    read in interface ImageInputStream
    
    Specified by:
    
    read in class ImageInputStreamImpl
    
    Returns:
    
    the value of the next byte in the stream, or -1 if EOF is reached.
    
    Throws:
    
    IOException - if the stream has been closed.
  - read
```
public int read(byte[] b,
                int off,
                int len)
         throws IOException
```
    Description copied from class: ImageInputStreamImpl
    
    Reads up to len bytes from the stream, and stores them into b starting at index off. If no bytes can be read because the end of the stream has been reached, -1 is returned.
    The bit offset within the stream must be reset to zero before the read occurs.
    
    Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.
    
    Specified by:
    
    read in interface ImageInputStream
    
    Specified by:
    
    read in class ImageInputStreamImpl
    
    Parameters:
    
    b - an array of bytes to be written to.
    
    off - the starting position within b to write to.
    
    len - the maximum number of bytes to read.
    
    Returns:
    
    the number of bytes actually read, or -1 to indicate EOF.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - length
```
public long length()
```
    Returns the length of the underlying file, or -1 if it is unknown.
    
    Specified by:
    
    length in interface ImageInputStream
    
    Overrides:
    
    length in class ImageInputStreamImpl
    
    Returns:
    
    the file length as a long, or -1.
  - seek
```
public void seek(long pos)
          throws IOException
```
    Description copied from interface: ImageInputStream
    
    Sets the current stream position to the desired location. The next read will occur at this location. The bit offset is set to 0.
    An IndexOutOfBoundsException will be thrown if pos is smaller than the flushed position (as returned by getflushedPosition).
    
    It is legal to seek past the end of the file; an java.io.EOFException will be thrown only if a read is performed.
    
    Specified by:
    
    seek in interface ImageInputStream
    
    Overrides:
    
    seek in class ImageInputStreamImpl
    
    Parameters:
    
    pos - a long containing the desired file pointer position.
    
    Throws:
    
    IOException - if any other I/O error occurs.
  - close
```
public void close()
           throws IOException
```
    Description copied from interface: ImageInputStream
    
    Closes the stream. Attempts to access a stream that has been closed may result in IOExceptions or incorrect behavior. Calling this method may allow classes implementing this interface to release resources associated with the stream such as memory, disk space, or file descriptors.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in interface ImageInputStream
    
    Overrides:
    
    close in class ImageInputStreamImpl
    
    Throws:
    
    IOException - if an I/O error occurs.
  - finalize
```
protected void finalize()
                 throws Throwable
```
    Finalizes this object prior to garbage collection. The close method is called to close any open input source. This method should not be called from application code.
    
    Overrides:
    
    finalize in class ImageInputStreamImpl
    
    Throws:
    
    Throwable - if an error occurs during superclass finalization.
    
    See Also:
    
    WeakReference, PhantomReference

Skip navigation links

Java™ Platform
Standard Ed. 8

All Classes

Summary:
Nested |
Field |
Constr |
Method

Detail:
Field |
Constr |
Method

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2022, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

Java javax.imageio.stream Class FileImageInputStream（JDK8）

Class FileImageInputStream

Field Summary

Fields inherited from class javax.imageio.stream.ImageInputStreamImpl

Constructor Summary

Method Summary

Methods inherited from class javax.imageio.stream.ImageInputStreamImpl

Methods inherited from class java.lang.Object

Constructor Detail

FileImageInputStream

FileImageInputStream

Method Detail

read

read

length

seek

close

finalize