JAVA streams and files

Flow

InputStream and OutputStream are super classes for all input and output streams. Both of them are abstract classes .

Both the Read method and the Write method are blocking methods , which means that if it is not possible to write or read, for example, because of network problems, the front-thread will be blocked.

InputStream's API:

Method Summary
int	available () Returns the number of bytes that the next caller of this input stream method can read (or skip) from this input stream in a blocked manner.
void	Close () closes this input stream and frees all system resources associated with the stream.
void	mark (int readlimit) marks the current position in this input stream.
Boolean	marksupported () tests whether this input stream supports the mark and reset methods.
Abstract int	Read () reads the next data byte from the input stream.
int	Read (byte[] b) reads a certain number of bytes from the input stream and stores it in buffer array B.
int	read (byte[] b, int off, int len) reads up to Len data bytes in the input stream into a byte array.
void	Reset () Repositions This stream to the location when the mark method was last called on this input stream.
Long	Skip (long N) Skips and discards n bytes of data in this input stream.

OutStream's API:

Method Summary
void	close () closes this output stream and frees all system resources related to this stream.
void	flush () refreshes this output stream and forces all buffered output bytes to be written out.
void	Write (byte[] b) writes B.length bytes from a specified byte array to this output stream.
void	write (byte[] b, int off, int len) writes to this output stream the Len bytes in the specified byte array starting at offset off.
abstract void	Write (int b) Writes the specified bytes to this output stream.

Reader and writer

Abstract class for reading and writing a stream of Unicode characters. Similar to the byte stream API.

Look at the following API, more than similar, part-time is the same. Because either the read byte or the Unicode character (which is actually a Unicode encoding unit, 2 bytes), the int type (4 bytes) is used as the parameter.

Method Summary
abstract void	Close () Closes the stream.
void	mark (int readaheadlimit) marks the current position in the stream.
Boolean	Marksupported () Determines whether this stream supports the mark () operation.
Int	Read () Reads a single character.
int	Read (char[] cbuf) reads the characters into the array.
Abstract int	Read (char[] cbuf, int off, int len) reads a character into a portion of the array.
int	Read (Charbuffer target) attempted to read a character into the specified character buffer.
Boolean	Ready () Determines whether the stream is ready to be read.
void	Reset () Resets the stream.
Long	Skip (long N) Skips a character.

Combined Flow Filter

Use as follows:

DataInputStream dis = new DataInputStream (new Bufferedinputstream (New FileInputStream ("Person.dat"));

Datainputstream/dataoutstream

The data input stream allows the application to read basic Java data types from the underlying input stream in a machine-independent manner . The application can use the data output stream to write data that is later read by the data input stream .

It's a way to see its common use scenarios:

Bufferedinputstream/bufferedoutstream

By maintaining a buffer internally, each time the Read method is executed, it is actually reading a fixed number of bytes into the memory buffer (through the construction parameters can be configured each time the number of bytes read, that is, the size of the buffer), and then the next time you read, directly from the memory buffer to take, Different in the original way (such as a network or a disk).

Write is also written to the internal buffer only when the buffer is full to make a real write operation.

JAVA streams and files