연습 문제1

C:\storage\prac1.txt 파일을 1글자씩 읽어서 C:\storage\prac1_copy.txt 파일로 보내고 걸린 시간 출력하기

• FileWriter, FileReader 사용, int read() 메소드 사용

		File src = new File("C:\\storage", "prac1.txt");
		File cpy = new File("C:\\storage", "prac1_copy.txt");
		FileReader fr = null;
		FileWriter fw = null;
		try {
			fr = new FileReader(src);
			fw = new FileWriter(cpy);
			int c;
			long begin = System.currentTimeMillis();
			 while((c = fr.read()) != -1) {
				 fw.write(c);
			 }
			 long end = System.currentTimeMillis();
			 System.out.println("복사시간 : " + (end - begin) * 0.001 + "초");
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				if(fw != null) fw.close();
				if(fr != null) fr.close();
			} catch(IOException e) {
				e.printStackTrace();
			}

연습 문제2

연습 문제 1 BufferedReader, BufferedWriter 사용해서 다시 풀기
(100글자씩 읽어서 보내기)

		File src = new File("C:\\storage", "prac1.txt");
		File cpy = new File("C:\\storage", "prac1_copy.txt");
		BufferedReader br = null;
		BufferedWriter bw = null;
		try {
			br = new BufferedReader(new FileReader(src));
			bw = new BufferedWriter(new FileWriter(cpy));
			char[] cbuf = new char[100];
			int readCnt = 0;
			long begin = System.currentTimeMillis();
			while((readCnt = br.read(cbuf)) != -1) {
				bw.write(cbuf, 0, readCnt);
			}
			long end = System.currentTimeMillis();
			System.out.println("복사시간 : " + (end - begin) * 0.001 + "초");
		} catch(IOException e) {
			e.printStackTrace();
		} finally {
			try {
				if(bw != null) bw.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

연습 문제3

이클립스 파일 복사하기, 복사한 파일 삭제하기

		File src = new File("C:\\GDJ\\installer", "eclipse-jee-2021-03-R-win32-x86_64.zip");
		File cpy = new File("C:\\GDJ\\installer", "eclipse.zip");
		BufferedInputStream bis = null;
		BufferedOutputStream bos = null;
		try {
			bis = new BufferedInputStream(new FileInputStream(src));
			bos = new BufferedOutputStream(new FileOutputStream(cpy));
			byte[] b = new byte[1024];  // 1KB
			int readByte = 0;
			while((readByte = bis.read(b)) != -1) {
				bos.write(b, 0, readByte);
			}
		} catch(IOException e) {
			e.printStackTrace();
		} finally {
			try {
			if(bos != null) bos.close();
			if(bis != null) bis.close();
		} catch(IOException e) {
			e.printStackTrace();
		}
		}

		File dir = new File("C:\\storage");
		if(dir.exists() == false) {
			dir.mkdirs();
		}
		File src = new File("C:\\GDJ\\installer", "eclipse.zip");
		File dst = new File(dir, src.getName());
		BufferedInputStream bis = null;
		BufferedOutputStream bos = null;
		try {
			bis = new BufferedInputStream(new FileInputStream(src));
			bos = new BufferedOutputStream(new FileOutputStream(dst));
			byte[] b = new byte[1024];
			int readByte = 0;
			while((readByte = bis.read(b)) != -1) {
				bos.write(b, 0, readByte);
			}
			bos.close();
			bis.close();
			// 원본과 복사본의 크기가 동일하면 원본을 제거
			if(src.length() == dst.length()) {
				src.deleteOnExit();
			}
		} catch(IOException e) {
			e.printStackTrace();
		}