java IO

InputSteam & OutputSteam

• InputStream (InputStreamReader)

BufferedInputStream : used as other input stream's wrapper.
ByteArrayInputStream : new ByteArrayInputStream(byteContent), A ByteArrayInputStream contains an internal buffer that contains bytes that may be read from the stream.
FileInputStream : new FileInputStream(path); read file

//seldom use
DataInputStream
ObjectInputStream : Read object from stream.
PipedInputStream :
PushbackInputStream
SequenceInputStream :

• OutputStream (OutputStreamWriter)

BufferedOutputStream
ByteArrayOutputStream
FileOutputStream
PrintStream : System.out
//seldom use
DataOutputStream
ObjectOutputStream
PipedOutputStream

通常用法

InputStream bin = null;
OutputStream bout = null;
byte[] buffer = new byte[1024];  //
int length;

try {
    bin = SomeInputStream();
    bout = SomeOutputStream();
   
    while((length = bin.read(buffer)) != -1) {
        bout.write(buffer, 0, length);
    }
} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
} finally {
    try {
        bin.close();
        bout.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Reader & Writer

• Reader

BufferedReader
CharArrayReader
FileReader
StringReader

 

//较少使用
PipedReader
PushbackReader

• Writer

BufferedWriter
CharArrayWriter
FileWriter
PrintWriter
StringWriter

 

//少用
PipedWriter

 

一些说明：

PrintWriter & PrintStream 最大特点就是它们提供了格式化的功能。pw.format("%s world", "hello");

 

Commons IO

IOUtils

This class provides static utility methods for input/output operations.

• closeQuietly - these methods close a stream ignoring nulls and exceptions
• toXxx/read - these methods read data from a stream
• write - these methods write data to a stream
• copy - these methods copy all the data from one stream to another
• contentEquals - these methods compare the content of two streams

FileUtils

 

• writing to a file
• reading from a file
• make a directory including parent directories
• copying files and directories
• deleting files and directories
• converting to and from a URL
• listing files and directories by filter and extension
• comparing file content
• file last changed date
• calculating a checksum

FilenameUtils

• the prefix - C:\
• the path - dev\project\
• the full path - C:\dev\project\
• the name - file.txt
• the base name - file
• the extension - txt