Java代码文件复制方法比较

最新推荐文章于 2022-03-06 21:25:10 发布

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本文探讨了两种Java代码文件复制方法，分别使用节点流和缓冲流进行文件复制。通过实验，结论指出利用缓冲流BufferedInputStream和BufferedOutputStream进行文件复制的效率显著提高。

import java.io.*;

public class CopyFile{

//文件通过节点流复制功能封装为方法

public void copyFile(String srcPath,String destPath){
    FileInputStream fis = null;
    FileOutputStream fos = null;
    try {
        //1.创建File类对象
        File srcFile = new File(srcPath);
        File destFile = new File(destPath);

        //2.创建输入流和输出流对象
        fis = new FileInputStream(srcFile);
        fos = new FileOutputStream(destFile);

        //3.数据的读入和写出操作
        byte[] bytes = new byte[1024];
        int len;
        while((len = fis.read(bytes)) != -1){
            fos.write(bytes,0,len);
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        //4.关闭流资源
        try {
            if(fis != null){
                fis.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            if(fos != null){
                fos.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

// //文件通过缓冲流复制功能封装为方法

public void copyFileWithBuffered(String srcPath,String destPath){
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;

        try {
            //1.创建File类对象
            File srcFile = new File(srcPath);
            File destFile = new File(destPath);

            //2.2.创建输入流和输出流对象
            //2.1创建节点流对象
            FileInputStream fis = new FileInputStream(srcFile);
            FileOutputStream fos = new FileOutputStream(destFile);

            //2.2创建缓冲流对象
            bis = new BufferedInputStream(fis);
            bos = new BufferedOutputStream(fos);

            //3.复制的细节：读取、写入
            byte[] buffer = new byte[1024];
            int len;
            while((len = bis.read(buffer)) != -1){
                bos.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //4.关闭资源
            //要求：先关闭外层的流，再关闭内层的流
            if(bos != null){
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(bis != null){
                try {
                    bis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            //说明：关闭外层流的同时，内层流也会关闭
//        fos.close();
//        fis.close();
        }
    }

}

class TestCopyFile{

public static void main(String[] args){

CopyFile copyFile = new CopyFile();

        long start = System.currentTimeMillis();

        String srcPath = "J:\\01.rar";
        String destPath = "C:\\Users\\qqq\\Desktop\\01.rar";
        copyFile.copyFile(srcPath,destPath);

        long end = System.currentTimeMillis();

        System.out.println("复制文件成功，耗时为：" + (end - start) + "毫秒");

System.out.println("---------------此处为分割线---------------");

        long start1 = System.currentTimeMillis();

        String srcPath = "J:\\01.rar";
        String destPath = "C:\\Users\\qqq\\Desktop\\01.rar";
        copyFile.copyFileWithBuffered(srcPath,destPath);

        long end1 = System.currentTimeMillis();

        System.out.println("复制文件成功，耗时为：" + (end1 - start1) + "毫秒");

}

结论：使用缓冲流BufferedInputStream、BufferedOutputStream后效率明显提升。