JAvaにおけるIOの変換フローとバッファフロー
01変換フローの概要
* A:
* a:
* OutputStreamWriter ： ，
* ， * A: _
* a.
* day24_source/ .JPG * A: OutputStreamWriter
* a: OutputStreamWriter
* java.io.OutputStreamWriter Writer
* ，
* write() ， ，
* ，
* OutputStreamWriter
* ：
* OutputStreamWriter(OuputStream out)
* ： FileOutputStream
* OutputStreamWriter(OutputStream out, String charsetName)
* String charsetName GBK UTF-8
* OutputStreamWriter ， FileWriter
* b:
public class OutputStreamWriterDemo {
public static void main(String[] args)throws IOException {
// writeGBK();
writeUTF();
}
/*
* OutputStreamWriter
* UTF-8
*/
public static void writeUTF()throws IOException{
// ，
FileOutputStream fos = new FileOutputStream("c:\\utf.txt");
// ， ， UTF-8
OutputStreamWriter osw = new OutputStreamWriter(fos,"UTF-8");
osw.write(" ");
osw.close();
}
/*
* OutputStreamWriter
* GBK
*/
public static void writeGBK()throws IOException{
// ，
FileOutputStream fos = new FileOutputStream("c:\\gbk.txt");
// ， ， ， GBK
OutputStreamWriter osw = new OutputStreamWriter(fos);
//
osw.write(" ");
osw.close();
}
}* A: _
* a: InputStreamReader
* java.io.InputStreamReader Reader
* ，
* ，
* :
* read() 1 ，
*
* OuputStreamWriter
* InputStreamReader
* OutputStreamWriter(OutputStream out)
* InputStreamReader(InputStream in)
* ： FileInputStream
* InputStreamReader(InputStream in,String charsetName)
* b:
* day24_source/ .JPG * A: InputSteamReader
* a:
public class InputStreamReaderDemo {
public static void main(String[] args) throws IOException {
// readGBK();
readUTF();
}
/*
* ,InputSteamReader
* UTF-8 , utf
*/
public static void readUTF()throws IOException{
// ,
FileInputStream fis = new FileInputStream("c:\\utf.txt");
// , , ,
InputStreamReader isr = new InputStreamReader(fis,"UTF-8");
char[] ch = new char[1024];
int len = isr.read(ch);
System.out.println(new String(ch,0,len));
isr.close();
}
/*
* ,InputSteamReader
* , GBK
*/
public static void readGBK()throws IOException{
// ,
FileInputStream fis = new FileInputStream("c:\\gbk.txt");
// , ,
InputStreamReader isr = new InputStreamReader(fis);
char[] ch = new char[1024];
int len = isr.read(ch);
System.out.println(new String(ch,0,len));
isr.close();
}
}* A:
* a:
OutputStreamWriter:
|--FileWriter:
InputStreamReader:
|--FileReader;
* b:
* OutputStreamWriter InputStreamReader ： 。 ： + 。
* FileWriter FileReader： ， 。
， ， ， 。
*
* InputStreamReader isr = new InputStreamReader(new FileInputStream("a.txt"));// 。
* InputStreamReader isr = new InputStreamReader(new FileInputStream("a.txt"),"GBK");// GBK 。
* FileReader fr = new FileReader("a.txt");* A:
* a:
* IO
* * A: BufferedOutputStream
* a: BufferedOutputStream
*
* java.io.BufferedOuputStream :
* BufferedOuputStream OutputStream
* , write ,
* :
* BufferedOuputStream(OuputStream out)
* , ,
* b:
public class BufferedOutputStreamDemo {
public static void main(String[] args)throws IOException {
// ,
//FileOutputStream fos = new FileOutputStream("c:\\buffer.txt");
// , ,
BufferedOutputStream bos = new
BufferedOutputStream(new FileOutputStream("c:\\buffer.txt"));
bos.write(55);
byte[] bytes = "HelloWorld".getBytes();
bos.write(bytes);
bos.write(bytes, 3, 2);
bos.close();
}
}* A: BufferedInputStream
* a: BufferedInputStream
*
* InputStream,
* read() ,
* :
* BufferedInputStream(InputStream in)
* , ,
* FileInputStream
* b:
public class BufferedInputStreamDemo {
public static void main(String[] args) throws IOException{
// , ,
BufferedInputStream bis = new
BufferedInputStream(new FileInputStream("c:\\buffer.txt"));
byte[] bytes = new byte[10];
int len = 0 ;
while((len = bis.read(bytes))!=-1){
System.out.print(new String(bytes,0,len));
}
bis.close();
}
}* A：
* a:
* 125250
* 193 OK
* 1210
* 73 OK
* b:
public class Copy {
public static void main(String[] args)throws IOException {
long s = System.currentTimeMillis();
copy_4(new File("c:\\q.exe"), new File("d:\\q.exe"));
long e = System.currentTimeMillis();
System.out.println(e-s);
}
/*
* ,
* 4.
*/
public static void copy_4(File src,File desc)throws IOException{
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(src));
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(desc));
int len = 0 ;
byte[] bytes = new byte[1024];
while((len = bis.read(bytes))!=-1){
bos.write(bytes,0,len);
}
bos.close();
bis.close();
}
/*
* ,
* 3.
*/
public static void copy_3(File src,File desc)throws IOException{
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(src));
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(desc));
int len = 0 ;
while((len = bis.read())!=-1){
bos.write(len);
}
bos.close();
bis.close();
}
/*
* ,
* 2.
*/
public static void copy_2(File src,File desc)throws IOException{
FileInputStream fis = new FileInputStream(src);
FileOutputStream fos = new FileOutputStream(desc);
int len = 0 ;
byte[] bytes = new byte[1024];
while((len = fis.read(bytes))!=-1){
fos.write(bytes,0,len);
}
fos.close();
fis.close();
}
/*
* ,
* 1.
*/
public static void copy_1(File src,File desc)throws IOException{
FileInputStream fis = new FileInputStream(src);
FileOutputStream fos = new FileOutputStream(desc);
int len = 0 ;
while((len = fis.read())!=-1){
fos.write(len);
}
fos.close();
fis.close();
}
}* A: BufferedWriter
* a: BufferedWriter
*
* java.io.BufferedWriter Writer
* write () , ,
* :
* BufferedWriter(Writer w)
* ,
* FileWriter, OutputStreamWriter
* b:
public class BufferedWrierDemo {
public static void main(String[] args) throws IOException{
// ,
FileWriter fw = new FileWriter("c:\\buffer.txt");
BufferedWriter bfw = new BufferedWriter(fw);
bfw.write(100);
bfw.flush();
bfw.write(" ".toCharArray());
bfw.flush();
bfw.write(" ");
bfw.flush();
bfw.write(" ");
bfw.flush();
bfw.write(" ");
bfw.flush();
bfw.close();
}
}* A: BufferedWriter newLine
* a:
* void newLine()
* newLine() , \r
*
* Windows \r
* Linux
* newLine() ,
* JVM: Windows ,newLine() \r
* Linux ,newLine()
/*
* c:\\a.txt
* d:\\a.txt
* ,
* ,
*
* , 1
* , 1
*/
* b:
public class BufferedWrierDemo {
public static void main(String[] args) throws IOException{
// ,
FileWriter fw = new FileWriter("c:\\buffer.txt");
BufferedWriter bfw = new BufferedWriter(fw);
bfw.write(100);
bfw.flush();
bfw.write(" ".toCharArray());
bfw.flush();
bfw.write(" ");
bfw.newLine();
bfw.flush();
bfw.write(" ");
bfw.newLine();
bfw.flush();
bfw.write(" ");
bfw.flush();
bfw.close();
}
}* A: BufferedReader
* a:
* ， ， 、
* public String readLine() ， ， ， ， null* A: BufferedReader
* a: BufferedReader
*
* java.io.BufferedReader Reader
* read() ,
* :
* BufferedReader(Reader r)
*
FileReader InputStreamReader
* BufferedReader
* String readLine() \r
* , null
* b:
*
* int
* null
* boolean false
* c:
public class BufferedReaderDemo {
public static void main(String[] args) throws IOException {
int lineNumber = 0;
// , ,
BufferedReader bfr = new BufferedReader(new FileReader("c:\\a.txt"));
// readLine()
// , readLine() null
String line = null;
while((line = bfr.readLine())!=null){
lineNumber++;
System.out.println(lineNumber+" "+line);
}
bfr.close();
}
}
/*
* String line = bfr.readLine();
System.out.println(line);
line = bfr.readLine();
System.out.println(line);
line = bfr.readLine();
System.out.println(line);
line = bfr.readLine();
System.out.println(line);
line = bfr.readLine();
System.out.println(line);
*/* A:
* a:
/*
* ,
* BufferedReader+FileReader
* BufferedWriter+FileWriter
* , , ,
*/
public class Copy_1 {
public static void main(String[] args) throws IOException{
BufferedReader bfr = new BufferedReader(new FileReader("c:\\w.log"));
BufferedWriter bfw = new BufferedWriter(new FileWriter("d:\\w.log"));
// , , ,
String line = null;
while((line = bfr.readLine())!=null){
bfw.write(line);
bfw.newLine();
bfw.flush();
}
bfw.close();
bfr.close();
}
}* A: IO
* a: ： 。
* ：InputStream Reader
* ：OutputStream Writer
* ， 。
* b: ： ？
* ：
* ：InputStream
* ：Reader
* ：
* ：OutputStream
* ：Writer
* c: ： 。
* ：
* ： File 。
* ： ， 。
* ：System.in;
* ：Socket
* ：
* ： File 。
* ： ， 。
* ：System.out
* ：Socket
* 。
* d: ： ？
* ：
* ？ 。InputStreamReader OutputStreamWriter
* ？ 。BufferedXXX
* 。