InputStream.. 3
OutputStream.. 4
/.. 5
. 5
File. 6
RandomAccessFile. 9
StreamTokenizer. 10
InputStreamReader OutputStreamWriter. 13
. 14
. 17
/ Java java.io. , , . : FileInputStream, FileOutputStream.
InputStream
InputStream . InputStream java.io , ( ) IOException:
public InputStream()
InputStream .
public abstract int read() throws IOException
, 0 255 ( 128 127). 1. .
public int read(byte[] buf)
. , buf , buf.length. 1 .
public int read(byte[] buf, int off, int len)
. , buf, off, len , buf.
public long skip(long count)
count . count - . .
public int available()
, .
public void close()
. (, ), . , , finalize .
OutputStream
OutputStream InputStream; , . , ( ) :
public OutputStream()
OutputStream .
public abstract void write(int b)
b. int, . , byte, int, int byte. , , 8 int 24 . .
|
|
|
public void write(byte[] buf)
. .
public void write(byte[] buf, int offset, int len)
, buf [offset] count , .
public void flush() throws IOException
, , .
public void close() throws IOException
. , .
/
/ Java FileInputStream FileOutputStream. :
String, .
File.
FileDescriptor.
FileDescriptor - , . getFD File RandomAccessFile. FileDescriptor File RandomAccessFile , , . , . , , , FileDescriptor.
flush FileOutputStream . , .
BufferedInputStream BufferedOutputStream , / . , .
, . byte , .
read BufferedInputStream, : read -, .
BufferedOutputStream. write , write -, .
|
|
|
, , :
OutputStream bufferedFile(String path)
throws IOExceptioon
{
OutputStream out = new FileOutputStream(path);
return new BufferedOutputStream(out);
}
FileOutputStream, BufferedOutputStream -. , .
FileOutputStream, , , - . , , .
File
File . , , .
File , . , , , File , exists.
. : ( ), . , char separatorChar String separator. .
File :
1. public File(String path)
File path. null, NullPointerException.
2. public File(String dirName, String name)
File name, dirName. dirName null, name. :
File(dirname + File.separator + name)
3. public File(File fileDir, String name)
File - fileDir File name. :
File(fileDir.getPath(), name)
get File. :
File src = new File("ok", "FileMethods");
System.out.println("getName() = " + src.getName());
System.out.println("getPath() = " + src.getPath());
System.out.println("getAbsolutePath() = "
+ src.getAbsolutePath());
System.out.println("getParent() = " + src.getParent());
:
getName() = FileMethods
getPath() = ok/FileMethods
getAbsolutePath() = /vob/java_prog/src/ok/FileMethods
getParent() = ok
, , File:
exists: true, .
canRead: true, .
canWrite: true, .
isFile: true, ( ).
isDirectory: true, .
isAbsolute: true, .
File :
public long lastModified()
. , , , . .
|
|
|
public long length()
.
public boolean mkdir()
true .
public boolean mkdirs()
, , true . , , , .
public boolean renameTo(File new_name)
true .
public boolean delete()
, File, true .
public String[] list()
. File , , null; . , . .. ( ).
public String[] list(FilenameFilter filter)
(. Filename Filter).
File.equals . File , , , . File.equals , File .
FileOutputStream RandomAccessFile, File.
, , File.pathSeparatorChar File.pathSeparator , . , UNIX : .:/bin:/usr/bin. , UNIX pathSepar a torChar .
String. File .
RandomAccessFile
RandomAccessFile , . Input Stream OutputStream, / . . Random AccessFile Data InputStream DataOutput Stream, / Java.
RandomAccessFile , read write. , , RandomAccessFile , InputStream OutputStream. , RandomAccessFile - DataInput DataOutput.
RandomAccessFile :
public RandomAccessFile(String name, String mode)
RandomAccessFile . r rw / . IOException.
|
|
|
public RandomAccessFile(File file, String mode)
RandomAccessFile File .
public RandomAccessFile(FileDescriptor fd)
RandomAccessFile fd File Descriptor (. FileDescriptor).
(random access), , / . :
public long getFilePointer()
( ) .
public void seek(long pos)
( ). pos.
public long length() throws IOException
.
StreamTokenizer
, java.io StreamTokenizer . 8 Unicode, Latin-1, , , 256 . , \u00ff, . (, ), , , ? (\u270D). .
, StreamTokenizer InputStream . nextToken, . , StreamTokenizer.
nextToken , ttype. :
TT_WORD: . sval String.
TT_NUMBER: . nval double. ( ). 3.4e79 , 0xffff .
TT_EOL: .
TT_EOF: .
. , , , , , . . , . , , ( ttype) int.
, :
public void wordChars(int low, int hi)
; TT_WORD. . , .
public void whitespaceChars(int low, int hi)
. ; , . wordChars, , -.
public void ordinaryChar (int ch)
ch . , .
public void ordinaryChars (int low, int hi)
.
public void commentChar (int ch)
ch ch .
public void quoteChar (int ch)
ch . , ch , sval ( -). Java \ (, \t), . , StreamTokenizer, Java. \xxxx, \, \" ( ) \Q, Q - ch. -, . , , -, ; -, .
|
|
|
public void parseNumbers()
. StreamTokenizer TT_NUMBER, nval. ordinaryChars , ( ), resetSyntax.
public void resetSyntax()
, . resetSyntax , nextToken , InputStream.read.
. StreamTokenizer:
1. wordChars(a, z);
2. wordChars(A, Z);
3. wordChars(128 + 32, 255);
4. whitespaceChars(0, );
5. commentChar(/);
6. quoteChar(");
7. quoteChar(\);
8. parseNumbers();
:
public void eolIsSignificant(boolean flag)
flag true, , nextToken TT_EOL. - TT_EOL . false.
public void slashStarComments(boolean flag)
flag true, /*...*/. false.
public void slashSlashComments(boolean flag)
flag true, // . false.
public void lowerCaseMode(boolean flag)
flag true, TT_WORD , ( String.toLowerCase). false.
:
public void pushBack()
. nextToken . ; pushBack .
public int lineno()
. .
public String toString()
, .
InputStreamReader OutputStreamWriter
java.io , Unicode -Unicode . InputStreamReader . OutputStreamWriter.
InputStreamReader OutputStreamWriter, , . , UTF-8 Unicode, :
FileInputStream fis = new FileInputStream("test.txt");
InputStreamReader isr = new InputStreamReader(fis, "UTF8");
, InputStreamReader OutputStreamWriter . , InputStreamReader OutputStreamWriter, getEncoding, :
InputStreamReader defaultReader = new InputStreamReader(fis);
String defaultEncoding = defaultReader.getEncoding();
, . :
1.
2.
3.
import java.io.*;
import java.util.Scanner;
public class Reader
{
private static String _encoding;
private static String _string;
public static void main(String[] args)
{
if (args.length!= 3)
{
System.out.println("Wrong number of input arguments");
return;
}
File testFile = new File(args[0]);
_encoding = args[1];
_string1 = args[2];
String contents = GetContents(testFile);
System.out.print("File contents:\r\n" + contents);
System.out.println("--------------------------------------------");
Analyze(contents);
}
static public String GetContents(File file)
{
StringBuilder contents = new StringBuilder();
try
{
if (file == null)
{
throw new IllegalArgumentException("File should not be null.");
}
if (!file.exists())
{
throw new FileNotFoundException();
}
if (!file.canRead())
{
throw new IllegalArgumentException("File cannot be written: " + file);
}
if (!file.isFile())
{
throw new IllegalArgumentException("Should not be a directory: " + file);
}
FileInputStream fis = new FileInputStream(file);
InputStreamReader in = new InputStreamReader(fis, _encoding);
BufferedReader input = new BufferedReader(in);
try
{
String line = null;
while ((line = input.readLine())!= null)
{
contents.append(line + "\r\n");
}
}
finally
{
input.close();
}
}
catch (FileNotFoundException ex)
{
System.out.println("File does not exist: " + file);
}
catch(IllegalArgumentException ex)
{
System.out.println(ex.getMessage());
}
catch (Exception ex)
{
ex.printStackTrace();
}
return contents.toString();
}
private static void Analyze(String contents)
{
Scanner scanner = new Scanner(contents);
int stringCount = 0;
while (scanner.hasNextLine())
{
Scanner s = new Scanner(scanner.nextLine());
while (s.hasNext())
{
String word = s.next();
if (word.contentEquals(_string))
stringCount++;
}
s.close();
}
scanner.close();
System.out.println(_string + " " + stringCount);
}
}
1. . : n-. ( , ) .
2. . : n-. ; , . .
3. , - ( \ ), . .
4. , ( , , 10 ). .
