File:.. 1 2. Files directory (folder) 3 pathname
IO stream for processing data transfer between devices
Press operation data is divided into two streams: byte stream and character stream.
com.oracle.demo01 Package;
Import java.io.FileNotFoundException;
Import java.io.FileOutputStream;
Import java.io.IOException;
public class Demo01 {
public static void main (String [] args) throws IOException {
// create a byte output stream object
// when this construction method designated addresses, Overwrite if exists, is automatically created if does not exist! (Must specify the file folder can not be)
a FileOutputStream fos = new new a FileOutputStream ( "D: \\ \\ d.txt Java");
// write a byte write to the file (int b) ASCII code
// 0 -48
// a -49
// -65 a
/ * fos.write (49);
fos.write (48);
fos.write (48); * /
// byte array to write a file write ( byte [] B)
// the BCDE
byte [] bytes = {- 66, -67, -68, -69, -70};
/*fos.write(bytes);*/
// where to start transmission of several
fos.write (bytes, 2,2 &);
// release resources
fos.close ();
}
}
com.oracle.demo01 Package;
Import java.io.FileNotFoundException;
Import java.io.FileOutputStream;
Import java.io.IOException;
public class Demo02 {
public static void main (String [] args) throws IOException {
// create a byte output stream (open writing function)
a FileOutputStream fos = new new a FileOutputStream ( "D: \\ \\ d.txt Java", to true);
// string ---> byte array the getBytes ();
fos.write ( " ABC ".getBytes ());
// newline \ R & lt \ n-
fos.write (" \ R & lt \ n-change line ".getBytes ());
// release resources
fos.close ();
}
}
If you do not open the writing mode, do not add any properties, the default is false
Recursion: In the current method which calls itself recursively called
Method void public () {
System.out.println ( "recursive call itself");
// current method calls itself in
Method ();
}
Recursion can be divided in two forms, a direct recursion, the other is indirect recursion
The method itself is a recursive direct call itself, can be called indirect recursion is A B, B calls in C, C A call to this form
Byte stream: What files can be copied
Byte output stream :: OutputStream
If after the end of Stream will certainly see as a stream of bytes, if not the end Stream is a stream of characters
close (): Before the release of resources to shut down automatically refresh
flush (): write once refreshed!
Clear data source: FileOutputStream fis = new FileOutputStream ( "write path");
com.oracle.demo01 Package;
Import a java.io.FileInputStream;
Import java.io.FileNotFoundException;
Import java.io.IOException;
public class Demo04 {
public static void main (String [] args) throws IOException {
// create a byte input stream (which clearly read from the file data)
the FileInputStream new new FIS = the FileInputStream ( "D: \\ \\ d.txt Java");
// read a byte
/ * int len = fis.read () ;
System.out.println ((char) len);
len = fis.read ();
System.out.println ((char) len);
len = fis.read ();
System.out.println ((char) len );
len = fis.read ();
System.out.println ((char) len);
len = fis.read ();
System.out.println ((char) len);
fis.read = len ();
System.out.println (len); * /
// read byte by byte file all data
int len = 0;
the while ((len = fis.read ()) = -. 1!) {
System.out.println (( char) len);
}
// release resources
fis.close ();
}
}
Input stream of bytes: InputStream
FileInputStream file data to read the input stream of bytes
1. 2. Create a data file to find the target input channel 3. The data resource file 4. Close
com.oracle.demo01 Package;
Import a java.io.FileInputStream;
Import java.io.FileNotFoundException;
Import java.io.IOException;
public class Demo05 {
public static void main (String [] args) throws IOException {
// clear the data source
= new new FIS the FileInputStream the FileInputStream ( "D: \\ \\ d.txt Java");
// Create a byte array
byte [] bytes = new new byte [2];
/ * read a byte array //
int len = fis.read (bytes);
valid number of bytes actually read //
System.out.println (len);
// byte array ----> byte string
System.out.println (new string (bytes )); * /
// read a byte array
int len = 0;
! the while ((len = fis.read (bytes)) = -. 1) {
System.out.println (new new String (bytes, 0, len));
}
// release resources
fis.close ();
}
}
Character stream: you can only copy the text file, what is a text file, open Notepad can read to understand is a text file!
The character input stream the base class: Reader
Transfer byte character streams: InputStreamReader // read character input byte stream
com.oracle.demo02 Package;
Import java.io.FileNotFoundException;
Import java.io.FileReader;
Import java.io.IOException;
public class Demo01 {
public static void main (String [] args) throws IOException {
// Create a character input stream
the FileReader the FileReader new new fr = ( "D: \\ \\ d.txt Java");
int len = 0;
// read character by character
while ((len = fr.read () ) = - 1!) {
System.out.println ((char) len);
}
// release resources
fr.close ();
}
}
com.oracle.demo02 Package;
Import java.io.FileNotFoundException;
Import java.io.FileReader;
Import java.io.IOException;
public class Demo02 {
public static void main (String [] args) throws IOException {
// Create a character input stream
the FileReader the FileReader new new fr = ( "D: \\ \\ d.txt Java");
// Create a character array
char [] = new new CH char [1024];
// read a character array of a character array
int len = 0;
the while ((len = fr.read (CH)) = -. 1!) {
System.out.println (new new String (CH, 0, len));
}
// release resources
fr.close ();
}
}
Character-output stream: writer
Writer is the top-level parent of all the characters of the output stream, and this class is an abstract class. Subclass generally used, most commonly subclass FileWriter.
{class Demo01Writer public
public static void main (String [] args) throws IOException {
// Create. 1
FileWriter FileWriter new new FW = ( "fiel05.txt");
// write 2
fw.write ( "starting in all but exceptional" );
// 3 refresh
fw.flush ();
// release. 4
fw.close ();
}
}
java.io.FileWriter Import;
Import java.io.IOException;
public class Demo03 {
public static void main (String [] args) throws IOException {
// create output character stream
FileWriter fw = new FileWriter ( "D : \\ java \ \ d.txt ");
// write a character
fw.write (100);
fw.flush ();
// write a character
fw.write (" starting in all but extraordinary ");
// write characters array
char [] = {CH 'A', '. 1', 'R & lt'};
fw.write (CH);
fw.flush ();
// release resources
fw.close ();
}
}