字节流

• 抽象基类 节点流（或文件流） 缓冲流（处理流的一种）
  InputStream FileInputStream BufferedFileInputStream
  OutputStream FileOutputStream BufferedFileOutputStream

/*
测试FileInputStream和FileOutputStream的使用

结论：
1，对于文本文件(.txt,.java,.c,.cpp)，使用字符流处理
2，对于非文本文件(.jpj,.mp3,.mp4,.doc,.ppt…..)，使用字节流处理
*

package com.atguigu.java1;
import org.junit.Test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
/**
 * 测试FileInputStream和FileOutputStream的使用
 *
 * 结论：
 * 1，对于文本文件(.txt,.java,.c,.cpp)，使用字符流处理
 * 2，对于非文本文件(.jpj,.mp3,.mp4,.doc,.ppt.....)，使用字节流处理
 *
 *
 * @author Dxkstart
 * @create 2021-05-30 12:41
 */
public class File_Input_OutputStream_Test {
    //使用字节流FileInputStream处理文本文件，可能出现乱码。
    @Test
    public void test_FileInputStream(){
        FileInputStream fis = null;
        try {
            //1.造文件
            File file = new File("Hello1.txt");
            //2.造流
            fis = new FileInputStream(file);
            //3.读数据
            byte[] buffer = new byte[5];
            int len;//记录每次读取的字节的个数
            while((len = fis.read(buffer)) != -1) {
                String str = new String(buffer, 0, len);
                System.out.print(str);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                //4.关闭流资源
                if(fis != null) {
                    fis.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    /*
    实现对图片的复制操作
     */
    @Test
    public void test_FileInput_OutputStream(){
        FileInputStream fis = null;
        FileOutputStream fos = null;
        try {
            //
            File file1 = new File("C:\\Users\\Administrator\\Desktop\\IO\\图片\\爱丽丝.jpg");
            File file2 = new File("爱丽丝1.jpg");
            //
            fis = new FileInputStream(file1);
            fos = new FileOutputStream(file2);
            //复制的过程
            byte[] buffer = new byte[5];
            int len;
            while((len = fis.read(buffer)) != -1){
                fos.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //
            try {
                if(fis != null) {
                    fis.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if(fos != null) {
                    fos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    //指定路径下文件的复制
    @Test
    public void copyFile(String srcPath,String destPath){
        FileInputStream fis = null;
        FileOutputStream fos = null;
        try {
            //
            File file1 = new File(srcPath);
            File file2 = new File(destPath);
            //
            fis = new FileInputStream(file1);
            fos = new FileOutputStream(file2);
            //复制的过程
            byte[] buffer = new byte[1024];
            int len;
            while((len = fis.read(buffer)) != -1){
                fos.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //
            try {
                if(fis != null) {
                    fis.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if(fos != null) {
                    fos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    @Test
    public void testCopyFile(){
        long start = System.currentTimeMillis();
        String srcPath = "C:\\Users\\Administrator\\Desktop\\IO\\图片\\螺旋丸.jpg";
        String destPath = "C:\\Users\\Administrator\\Desktop\\IO\\图片\\螺旋丸2.jpg";
        copyFile(srcPath,destPath);
        long end = System.currentTimeMillis();
        System.out.println("复制操作花费的时间为：" + (end - start));
    }
}

package com.atguigu.java1;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
/**
 * @author Dxkstart
 * @create 2021-05-30 14:13
 */
public class testCopy {
    public static void main(String[] args) {
        long start = System.currentTimeMillis();
        String srcPath = "C:\\Users\\Administrator\\Desktop\\IO\\视频\\01.mp4";
        String destPath = "C:\\Users\\Administrator\\Desktop\\IO\\视频\\02.mp4";
        new copy().copyFile(srcPath,destPath);
        long end = System.currentTimeMillis();
        System.out.println("复制操作花费的时间为：" + (end - start)); //380ms
    }
}
class copy{
    public void copyFile(String srcPath,String destPath){
        FileInputStream fis = null;
        FileOutputStream fos = null;
        try {
            //
            File file1 = new File(srcPath);
            File file2 = new File(destPath);
            //
            fis = new FileInputStream(file1);
            fos = new FileOutputStream(file2);
            //复制的过程
            byte[] buffer = new byte[102400];
            int len;
            while((len = fis.read(buffer)) != -1){
                fos.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //
            try {
                if(fis != null) {
                    fis.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if(fos != null) {
                    fos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}