java学习---------IO流学习---文件流inputstream outputstream(二)

	// 从指定的文件中读取内容，并写入到指定的文件内（相当于文件的复制）
	@Test
	public void testFileInputOutputStream() {
		File src = new File("file/iotest.txt");//源文件
		File des = new File("file/outputstream.txt");//目标文件

		FileInputStream fis = null;//输入流，读
		FileOutputStream fos = null;//输出流，写

		try {
			fis = new FileInputStream(src);//构造
			fos = new FileOutputStream(des);

			byte[] b = new byte[10];//字节数组
			int len;
			while ((len = fis.read(b)) != -1) {//从源文件中的输入流中读
				fos.write(b, 0, len);//每读10字节就写进去，写到目标文件
				//特别注意：这种写法将会把目标文件的原来内容给覆盖掉
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (fos != null)
					fos.close();//关闭写操作
			} catch (IOException e) {
				e.printStackTrace();
			}
			try {
				if (fis != null)
					fis.close();//关闭读操作
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	public void copyFile(String src, String des) {
		File file1 = new File(src);
		File file2 = new File(des);

		FileInputStream fis = null;
		FileOutputStream fos = null;

		try {
			fis = new FileInputStream(file1);
			fos = new FileOutputStream(file2);

			byte[] b = new byte[1024];
			int len;
			while ((len = fis.read(b)) != -1) {
				fos.write(b, 0, len);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (fos != null)
					fos.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
			try {
				if (fis != null)
					fis.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	/**通过使用FileReader和FileWriter实现文件的复制
	 * Reader和Writer是一个字符流，也就是16bit
	 * @param src
	 * @param des
	 */
	public void copyFile(String src, String des) {
		File file1 = new File(src);
		File file2 = new File(des);

		FileReader fr = null;
		FileWriter fw = null;

		try {
			fr = new FileReader(file1);//构造
			fw = new FileWriter(file2);

			char[] b = new char[1024];//字符数组
			int len;
			while ((len = fr.read(b)) != -1) {
				fw.write(b, 0, len);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (fw != null)
					fw.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
			try {
				if (fr != null)
					fr.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	/**通过缓冲流实现文件的复制（可以调高文件复制的效率）
	 * 对于输出的缓冲流，写出的数据会先在内存中缓存，
	 * 使用flush()将会使内存中的数据立刻写出
	 */
	@Test
	public void testBufferedInputStreamOutputStream() {
		long start = System.currentTimeMillis();
		// 1.
		File file1 = new File("C:/Users/dell/Desktop/spider.rar");
		File file2 = new File("file/1.rar");
		// 2.
		FileInputStream fis = null;//输入流
		FileOutputStream fos = null;//输出流
		BufferedInputStream bis = null;//缓冲输入流
		BufferedOutputStream bos = null;//缓冲输出流
		try {
			fis = new FileInputStream(file1);//构造
			fos = new FileOutputStream(file2);

			// 3.
			bis = new BufferedInputStream(fis);//缓冲流的构造
			bos = new BufferedOutputStream(fos);
			
			byte[] b = new byte[1024];//字节数组，每次读取1024字节
			int len;
			while((len = bis.read(b)) != -1){
				bos.write(b, 0, len);
				bos.flush();//这句非常的重要，flush()将会使内存中的数据立刻写出
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			if(bos != null){
				try {
					bos.close();//关闭缓冲流时,会自动关闭它所包装的底层节点流
				} catch (IOException e) {
					e.printStackTrace();
				}
			}			
			if(bis != null){
				try {
					bis.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		long end = System.currentTimeMillis();
		System.out.println("spend time:" + (end - start));
	}

	public void copyFile(String src, String des) {
		long start = System.currentTimeMillis();
		// 1.
		File file1 = new File(src);
		File file2 = new File(des);
		// 2.
		FileInputStream fis = null;//输入流
		FileOutputStream fos = null;//输出流
		BufferedInputStream bis = null;//缓冲输入流
		BufferedOutputStream bos = null;//缓冲输出流
		try {
			fis = new FileInputStream(file1);//构造
			fos = new FileOutputStream(file2);

			// 3.
			bis = new BufferedInputStream(fis);//缓冲流的构造
			bos = new BufferedOutputStream(fos);
			
			byte[] b = new byte[1024];//字节数组，每次读取1024字节
			int len;
			while((len = bis.read(b)) != -1){
				bos.write(b, 0, len);
				bos.flush();//这句非常的重要，flush()将会使内存中的数据立刻写出
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			if(bos != null){
				try {
					bos.close();//关闭缓冲流时,会自动关闭它所包装的底层节点流
				} catch (IOException e) {
					e.printStackTrace();
				}
			}			
			if(bis != null){
				try {
					bis.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		long end = System.currentTimeMillis();
		System.out.println("spend time:" + (end - start));
	}