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This article mainly introduces "Java IO stream file management analysis". In the daily operation, I believe that many people have doubts about the management and analysis of Java IO stream files. The editor has consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "Java IO stream file management analysis". Next, please follow the editor to study!

I. IO stream classification

1. Classification angle

Direction of flow

Input stream: a stream that reads data from a data source to an application

Output stream: a stream that writes data from an application to a destination

Stream data type

Byte stream: a stream that is read and written in bytes, with a name ending in Stream

Character stream: a stream that is read and written in character form, with the name ending in Writer and Reader

Pipe flow: processed in blocks, and buffers are blocks used for reading and writing

The role of stream

Node flow: a stream that can read / write data from or to a node, also known as a low-level stream

Processing flow: a stream that is connected or encapsulated to read / write an existing stream, also known as an advanced stream.

2. API system

5 core classes ObjectOutputStream:File, OutputStream, InputStream, Writer, Reader

1 key interface: Serializable

II. Classification of API details

1. Byte input stream

InputStream: the byte input stream is the parent of all byte input streams, provides a standard for all byte input streams, and basic methods and simple implementations related to reading bytes.

FileInputStream: the file byte input stream reads the data in the file into the application in the form of bytes

BufferedInputStream: buffering byte input stream, providing buffering function and improving efficiency

ByteArrayInputStream: the byte array input stream is used to read bytes from its built-in cache byte array

PipedInputStream: the pipe byte input stream must be used in conjunction with PipedOutputStream for communication between threads

FilterInputStream: filters byte input streams, overrides InputStream methods, and provides extensions for byte input processing streams

DataInputStream: data byte input stream, usually used in conjunction with DataOutputStream

ObjectInputStream: object byte input stream, used in conjunction with ObjectOutputStream

2. Byte output stream

OutputStream: byte output stream, the function of InputStream is the same, providing a standard for all byte output stream, defining some basic output bytes and simple implementation.

FileOutputStream: file byte output stream that writes bytes to the file source at the specified destination

BufferedOutputStream: buffered byte output stream, providing buffering function and improving efficiency

ByteArrayOutputStream: byte array output stream that writes bytes to a built-in cache byte array that comes with it.

PipedoutputStream: pipe byte output stream, which must be used in conjunction with PipedInputStream for communication between threads

FilterOutputStream: filters byte output streams to provide extensions for byte output processing streams

DataOutputStream: data byte output stream, usually used in conjunction with DataInputStream

ObjectOutputStream: object byte output stream, usually used in conjunction with ObjectInputStream

PrintStream: byte print streams, byte output streams are decorated and provide the ability to print various data types

3. Character input stream

Reader: character input stream that provides a standard, basic definition of reading methods and simple implementation for all character input streams

InputStreamReader: byte conversion stream that converts a byte stream to a character stream and can specify the encoding to be used when bytes are converted to characters

BufferedReader: buffering character input stream, providing buffering function for character input stream and improving efficiency

CharArrayReader: character array input stream that reads data from its built-in character cache array into the application

PipedReader: pipe character input stream, used in conjunction with PipedWriter for communication between threads

FilterReader: filters the character input stream to provide extensions for the character input stream

FileReader: file character input stream, which reads the contents of the file in the form of characters

4. Character output stream

Writer: character output stream, all character output streams provide a standard, basic writing method and simple implementation

OutputStreamWriter: a byte output conversion stream that converts a byte output stream into a character output stream. You can specify a coding conversion

BufferedWriter: caching character output stream, providing buffering function and improving efficiency

CharArrayWriter: character output stream for writing characters to its built-in cache character array

PipedWriter: pipe character output stream, used in conjunction with PipedReader for communication between threads

FileWriter: file character output stream, which is used to write characters to a specified file

PrintWriter: character printing stream, printing all kinds of data as characters

III. File file class

1. Construction method

File (String pathname): create a File file by specifying the path to a file or folder

File (File parent,String child): creates a new File instance based on parent abstract pathname and child pathname character

2. Path problem

Absolute path: the full path of the file on the hard drive. Absolute paths usually start with a drive letter.

Relative path: the relative path is the path of the resource file relative to the current program.

. Current path

.. Upper-level path

3. File creation

CreateNewFile (): creates an empty file in the specified location, returns true successfully, does not create it if it already exists, and then returns false

Mkdir (): creates a directory at the specified location, which only creates the last level directory. If the parent directory does not exist, an exception is thrown.

Mkdirs (): creates a directory at the specified location, which creates all directories that do not exist in the path

4. Delete files

Delete () deletes a file or an empty folder. If the folder is not empty, it cannot be deleted. It returns true if it succeeds, or false if it fails.

5. Judgment method

Exists (): whether a file or folder exists

IsFile (): whether it is a file, and if it does not exist, it is always false

IsDirectory (): whether it is a directory, and if it does not exist, it is always false

6. Get file information

GetName (): gets the file or folder name without the parent path

GetPath (): returns an absolute path, which can be a relative path, but the directory should be specified

IV. Coding and decoding

The byte stream reads the binary data in the file and is not automatically converted into intelligible characters; character stream: encodes and decodes the read data accordingly.

At this point, the study on "Java IO stream file management analysis" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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