字节缓冲流的使用

• 缓冲流:BufferedInputStream/BufferedOutPutStream
  • 提高IO效率,减少访问磁盘的次数
  • 数据存储在缓冲区中,flush是将缓冲区的内容写入文件中,也可以直接close.

BufferedInputStream

package stream;

import java.io.BufferedInputStream;
import java.io.FileInputStream;

/*
使用字节缓冲流读取
BufferedInputStream
 */
public class Demo05 {
    public static void main(String[] args)throws Exception {
        //1.创建BufferedInputStream
        FileInputStream fis = new FileInputStream("e:\\aaa.txt");
        BufferedInputStream bis = new BufferedInputStream(fis);//增强
        //2.读取缓冲区

        int data = 0;
        while ((data=bis.read())!=-1){
            System.out.print((char)data);
        }
        //3.关闭
        bis.close();
        System.out.println();
        System.out.println("程序结束");
    }
}
//缓冲区中最多存储8k的东西

//也可以这样写,一次读取多个
package stream;
import java.io.BufferedInputStream;
import java.io.FileInputStream;

/*
使用字节缓冲流读取
BufferedInputStream
 */
public class Demo05 {
    public static void main(String[] args)throws Exception {
        //1.创建BufferedInputStream
        FileInputStream fis = new FileInputStream("e:\\aaa.txt");
        BufferedInputStream bis = new BufferedInputStream(fis);//增强
        //2.读取缓冲区
        byte[] buf = new byte[1024];
        int data = 0;
        while ((data=bis.read(buf))!=-1){
            System.out.println(new String(buf,0,data));
        }
        //3.关闭
        bis.close();
        System.out.println();
        System.out.println("程序结束");
    }
}

BufferOutputStream

package stream;

import java.io.BufferedOutputStream;
import java.io.FileOutputStream;

/**
 * 使用字节缓冲流写入文件
 * BufferedOutputStream
 *
 */
public class Demo06 {
    public static void main(String[] args)throws Exception {
        //创建字节输出缓冲流
        FileOutputStream fos = new FileOutputStream("e:\\buffer.txt",true);//可以继续写
        BufferedOutputStream bos = new BufferedOutputStream(fos);
        //2.写入文件
        for (int i = 0; i < 10; i++) {
            bos.write("helloworld\r\n".getBytes());//写入8k的缓冲区中
            bos.flush();//刷新到硬盘
        }
        //关闭(内部会调用flush())
        bos.close();
    }
}