Java IO流--使用FileInputStream和FileOutputStream复制图片和文件

Posted 2021-07-11 路宇_

一、复制图片

 @Test
    public void test2(){
        FileInputStream fis = null;
        FileOutputStream fos = null;
        try {
            //1.提供File类的对象
            File file1 = new File("工作二维码.png");
            File file2 = new File("工作二维码3.png");

            //2.造流
            fis = new FileInputStream(file1);
            fos = new FileOutputStream(file2);

            //3.复制图片
            byte[] buffer = new byte[5];
            int len;
            while ((len=fis.read(buffer))!=-1){
                fos.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //4.关闭资源
            if (fis!=null){
                try {
                    fis.close();
                }catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fos!=null){
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

二、复制文件

//指定路径下文件的复制
    public void copyFile(String srcPath,String descPath){
        FileInputStream fis = null;
        FileOutputStream fos = null;
        try {
            //1.提供File类的对象
            File file1 = new File(srcPath);
            File file2 = new File(descPath);

            //2.造流
            fis = new FileInputStream(file1);
            fos = new FileOutputStream(file2);

            //3.复制图片
            byte[] buffer = new byte[1024];
            int len;
            while ((len=fis.read(buffer))!=-1){
            	//void write(byte[] b ,int off, int len)
            	//将byte[]数组下标off开始的len长度的数据写入当前输出流
                fos.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //4.关闭资源
            if (fis!=null){
                try {
                    fis.close();
                }catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fos!=null){
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    @Test
    public void testCopyFile(){
        long start = System.currentTimeMillis();

        String srcPath="C:\\\\Users\\\\DELL\\\\Desktop\\\\1.回顾类-封装和继承.mp4";
        String descPath= "C:\\\\Users\\\\DELL\\\\Desktop\\\\1.回顾类-封装和继承3.mp4";

        copyFile(srcPath,descPath);

        long end = System.currentTimeMillis();

        System.out.println("复制消耗的时间："+(end-start));
    }