IO流——（字節流）OutputStream和InputStream

/*
字符流：
FileReader
FileWriter。

BufferedReader
BufferedWriter

字節流：
InputStream  OutputStream

需求，想要操作圖片數據。這時就要用到字節流。
複製一個圖片.


*/
import java.io.*;
class  FileStream
{
	public static void main(String[] args) throws IOException
	{
		readFile_3();
	}

	public static void readFile_3()throws IOException
	{
		FileInputStream fis = new FileInputStream("fos.txt");
		
//		int num = fis.available();
		byte[] buf = new byte[fis.available()];//定義一個剛剛好的緩衝區。不用再循環了。

		fis.read(buf);

		System.out.println(new String(buf));

		fis.close();
	}


	public static void readFile_2()throws IOException
	{
		FileInputStream fis = new FileInputStream("fos.txt");

		byte[] buf = new byte[1024];
		int len = 0;
		while((len=fis.read(buf))!=-1)
		{
			System.out.println(new String(buf,0,len));
		}

		fis.close();
		
	}



	public static void readFile_1()throws IOException
	{
		FileInputStream fis = new FileInputStream("fos.txt");

		int ch = 0;

		while((ch=fis.read())!=-1)
		{
			System.out.println((char)ch);
		}

		fis.close();
	}

	public static void writeFile()throws IOException
	{
		FileOutputStream fos = new FileOutputStream("fos.txt");
		

		fos.write("abcde".getBytes());

		fos.close();

		
	}
}