package com.cn.buffered;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
/**
 * Desc：
需求：使用缓冲输入输出数组字节流拷贝一张图片。
 */
public class Demo3 {
    public static void main(String[] args) {
        BufferedInputStream bufferedInputStream = null;
        BufferedOutputStream bufferedOutputStream = null;
        try{
            //找到目标文件
            File file = new File("f:/cool.png");
            File descFile = new File("f:/cool2.png");
            //建立数据输入输出通道
            FileInputStream inputStream = new FileInputStream(file);
            FileOutputStream fileOutputStream = new FileOutputStream(descFile);
            //建立缓冲输入输出通道
            bufferedInputStream = new BufferedInputStream(inputStream);
            bufferedOutputStream = new BufferedOutputStream(fileOutputStream);
            //边读边写
            int content = 0;
            while((content = bufferedInputStream.read()) != -1){//read()方法返回值是读取到的内容
                bufferedOutputStream.write(content);
//                bufferedOutputStream.flush();  //这里加了flush()的话效率就会变低、但后面必须加close方法，把内存中的数据输出
            }
        }catch(IOException e){
            System.out.println("打开资源文件出现异常。。。。");
            throw new RuntimeException(e); 
        }finally{
            try {
                if(bufferedOutputStream != null){
                    bufferedOutputStream.close();
                    System.out.println("缓冲输出字节流关闭成功。。。。");
                }
            } catch (IOException e) {
                System.out.println("缓冲输出字节流关闭失败。。。。");
                throw new RuntimeException(e); 
            }finally{
                try{
                    if(bufferedOutputStream != null){
                        bufferedInputStream.close();
                        System.out.println("缓冲输入字节流关闭成功。。。。");
                    }
                }catch(IOException e){
                    System.out.println("缓冲输入字节流关闭失败。。。。");
                    throw new RuntimeException(e); 
                }
            }
        }
    }
}