23: JAVA stream

1. I/O 스트림 이란?

• Input or output from one direction like drinking straw.

2. 필터스트림이란?

• It provides additional functions during transforming data.

3. I/O 스트림을 이용하여, 아래와 같이 파일 복사프로그램을 만드시오.

대상 파일: a.jpeg
사본 이름: b.jpeg

//
//code
//
import java.io.*;
class Const {
    static final String EXTENSION_JPEG = ".jpeg";
    static final String DIR = "";
    static final String NAME_A = "a";
    static final String NAME_B = "b";
}
class Functions {
    static void run() {
        while(true) {
            try {
                inputAndOutputStream();
                break;
            } catch(Exception e) {
                e.printStackTrace();
            };
        };
    }
    private static String fileAddress(String name, String extention) {
        return (fileAddress(name, extention, Const.DIR));
    }
    private static String fileAddress(String name, String extention, String directory) {
        return (directory.concat(name).concat(extention));
    }
    private static void inputAndOutputStream() {
        String oNameTarget = fileAddress(Const.NAME_A, Const.EXTENSION_JPEG);
        String oNameCopy = fileAddress(Const.NAME_B, Const.EXTENSION_JPEG);
        try(InputStream inputStream = new FileInputStream(oNameTarget); 
            OutputStream outputStream = new FileOutputStream(oNameCopy)) {
            int data;
            while(true) {
                data = inputStream.read();
                if (data == -1) {
                    break;
                } else {
                    outputStream.write(data);
                };
            };
        } catch(IOException e) {
            e.printStackTrace();
        };
    }
}
class InputAndOutputStreamMain {
    public static void main(String[] args) {
        Functions.run();
    }
}

4.버퍼링의 의미와 Buffered 필터스트림에 대하여 설명하시오.

• Buffering: Occupying the memory in advance.
• Buffered filter stream: It can control how many bytes get processed for one logic. The code with buffered stream can be much more faster than without it.