FileInputStream (Java SE 9 & JDK 9 ) (original) (raw)
Constructor Detail
* #### FileInputStream
public FileInputStream([String](../../java/lang/String.html "class in java.lang") name)
throws [FileNotFoundException](../../java/io/FileNotFoundException.html "class in java.io")
Creates a `FileInputStream` by opening a connection to an actual file, the file named by the path name `name` in the file system. A new `FileDescriptor` object is created to represent this file connection.
First, if there is a security manager, its `checkRead` method is called with the `name` argument as its argument.
If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a`FileNotFoundException` is thrown.
Parameters:
`name` \- the system-dependent file name.
Throws:
`[FileNotFoundException](../../java/io/FileNotFoundException.html "class in java.io")` \- if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.
`[SecurityException](../../java/lang/SecurityException.html "class in java.lang")` \- if a security manager exists and its`checkRead` method denies read access to the file.
See Also:
[SecurityManager.checkRead(java.lang.String)](../../java/lang/SecurityManager.html#checkRead-java.lang.String-)
* #### FileInputStream
public FileInputStream([File](../../java/io/File.html "class in java.io") file)
throws [FileNotFoundException](../../java/io/FileNotFoundException.html "class in java.io")
Creates a `FileInputStream` by opening a connection to an actual file, the file named by the `File` object `file` in the file system. A new `FileDescriptor` object is created to represent this file connection.
First, if there is a security manager, its `checkRead` method is called with the path represented by the `file` argument as its argument.
If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a`FileNotFoundException` is thrown.
Parameters:
`file` \- the file to be opened for reading.
Throws:
`[FileNotFoundException](../../java/io/FileNotFoundException.html "class in java.io")` \- if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.
`[SecurityException](../../java/lang/SecurityException.html "class in java.lang")` \- if a security manager exists and its`checkRead` method denies read access to the file.
See Also:
[File.getPath()](../../java/io/File.html#getPath--), [SecurityManager.checkRead(java.lang.String)](../../java/lang/SecurityManager.html#checkRead-java.lang.String-)
* #### FileInputStream
public FileInputStream([FileDescriptor](../../java/io/FileDescriptor.html "class in java.io") fdObj)
Creates a `FileInputStream` by using the file descriptor`fdObj`, which represents an existing connection to an actual file in the file system.
If there is a security manager, its `checkRead` method is called with the file descriptor `fdObj` as its argument to see if it's ok to read the file descriptor. If read access is denied to the file descriptor a `SecurityException` is thrown.
If `fdObj` is null then a `NullPointerException` is thrown.
This constructor does not throw an exception if `fdObj` is [invalid](../../java/io/FileDescriptor.html#valid--). However, if the methods are invoked on the resulting stream to attempt I/O on the stream, an `IOException` is thrown.
Parameters:
`fdObj` \- the file descriptor to be opened for reading.
Throws:
`[SecurityException](../../java/lang/SecurityException.html "class in java.lang")` \- if a security manager exists and its`checkRead` method denies read access to the file descriptor.
See Also:
[SecurityManager.checkRead(java.io.FileDescriptor)](../../java/lang/SecurityManager.html#checkRead-java.io.FileDescriptor-)
Method Detail
* #### read
public int read()
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads a byte of data from this input stream. This method blocks if no input is yet available.
Specified by:
`[read](../../java/io/InputStream.html#read--)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")`
Returns:
the next byte of data, or `-1` if the end of the file is reached.
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs.
* #### read
public int read(byte[] b)
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads up to `b.length` bytes of data from this input stream into an array of bytes. This method blocks until some input is available.
Overrides:
`[read](../../java/io/InputStream.html#read-byte:A-)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")`
Parameters:
`b` \- the buffer into which the data is read.
Returns:
the total number of bytes read into the buffer, or`-1` if there is no more data because the end of the file has been reached.
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs.
See Also:
[InputStream.read(byte\[\], int, int)](../../java/io/InputStream.html#read-byte:A-int-int-)
* #### read
public int read(byte[] b,
int off,
int len)
throws [IOException](../../java/io/IOException.html "class in java.io")
Reads up to `len` bytes of data from this input stream into an array of bytes. If `len` is not zero, the method blocks until some input is available; otherwise, no bytes are read and `0` is returned.
Overrides:
`[read](../../java/io/InputStream.html#read-byte:A-int-int-)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")`
Parameters:
`b` \- the buffer into which the data is read.
`off` \- the start offset in the destination array `b`
`len` \- the maximum number of bytes read.
Returns:
the total number of bytes read into the buffer, or`-1` if there is no more data because the end of the file has been reached.
Throws:
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- If `b` is `null`.
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- If `off` is negative,`len` is negative, or `len` is greater than`b.length - off`
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs.
See Also:
[InputStream.read()](../../java/io/InputStream.html#read--)
* #### skip
public long skip(long n)
throws [IOException](../../java/io/IOException.html "class in java.io")
Skips over and discards `n` bytes of data from the input stream.
The `skip` method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly `0`. If `n` is negative, the method will try to skip backwards. In case the backing file does not support backward skip at its current position, an `IOException` is thrown. The actual number of bytes skipped is returned. If it skips forwards, it returns a positive value. If it skips backwards, it returns a negative value.
This method may skip more bytes than what are remaining in the backing file. This produces no exception and the number of bytes skipped may include some number of bytes that were beyond the EOF of the backing file. Attempting to read from the stream after skipping past the end will result in -1 indicating the end of the file.
Overrides:
`[skip](../../java/io/InputStream.html#skip-long-)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")`
Parameters:
`n` \- the number of bytes to be skipped.
Returns:
the actual number of bytes skipped.
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if n is negative, if the stream does not support seek, or if an I/O error occurs.
* #### available
public int available()
throws [IOException](../../java/io/IOException.html "class in java.io")
Returns an estimate of the number of remaining bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream. Returns 0 when the file position is beyond EOF. The next invocation might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.
In some cases, a non-blocking read (or skip) may appear to be blocked when it is merely slow, for example when reading large files over slow networks.
Overrides:
`[available](../../java/io/InputStream.html#available--)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")`
Returns:
an estimate of the number of remaining bytes that can be read (or skipped over) from this input stream without blocking.
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if this file input stream has been closed by calling`close` or an I/O error occurs.
* #### close
public void close()
throws [IOException](../../java/io/IOException.html "class in java.io")
Closes this file input stream and releases any system resources associated with the stream.
If this stream has an associated channel then the channel is closed as well.
Specified by:
`[close](../../java/lang/AutoCloseable.html#close--)` in interface `[AutoCloseable](../../java/lang/AutoCloseable.html "interface in java.lang")`
Specified by:
`[close](../../java/io/Closeable.html#close--)` in interface `[Closeable](../../java/io/Closeable.html "interface in java.io")`
Overrides:
`[close](../../java/io/InputStream.html#close--)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")`
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs.
* #### getFD
public final [FileDescriptor](../../java/io/FileDescriptor.html "class in java.io") getFD()
throws [IOException](../../java/io/IOException.html "class in java.io")
Returns the `FileDescriptor` object that represents the connection to the actual file in the file system being used by this `FileInputStream`.
Returns:
the file descriptor object associated with this stream.
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs.
See Also:
[FileDescriptor](../../java/io/FileDescriptor.html "class in java.io")
* #### getChannel
public [FileChannel](../../java/nio/channels/FileChannel.html "class in java.nio.channels") getChannel()
Returns the unique [FileChannel](../../java/nio/channels/FileChannel.html "class in java.nio.channels") object associated with this file input stream.
The initial [position](../../java/nio/channels/FileChannel.html#position--) of the returned channel will be equal to the number of bytes read from the file so far. Reading bytes from this stream will increment the channel's position. Changing the channel's position, either explicitly or by reading, will change this stream's file position.
Returns:
the file channel associated with this file input stream
Since:
1.4
* #### finalize
[@Deprecated](../../java/lang/Deprecated.html "annotation in java.lang")([since](../../java/lang/Deprecated.html#since--)="9")
protected void finalize()
throws [IOException](../../java/io/IOException.html "class in java.io")
Deprecated.
Ensures that the `close` method of this file input stream is called when there are no more references to it.
Overrides:
`[finalize](../../java/lang/Object.html#finalize--)` in class `[Object](../../java/lang/Object.html "class in java.lang")`
Throws:
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs.
See Also:
[close()](../../java/io/FileInputStream.html#close--)