黑马程序员_IO流——FileStream

/*
字符流：
FileReader
FileWriter。

BufferedReader
BufferedWriter

字节流：
InputStream  OutputStream

需求，想要操作图片数据。这时就要用到字节流。
复制一个图片.

*/
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()];//定义一个刚刚好的缓冲区。不用在循环了。用来操作小数据，数据量太大的话会出现内存溢出

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();

}
}