Java 读取某文件下的所有文件名称以及大小，并输出在xls表格里

方法一： 

package com.test.demo.test;

import lombok.Data;
import java.io.*;
import java.util.ArrayList;
import java.util.List;

/**
 * @Title: GetFileSize.java
 * @Project: byy
 * @Description: 获取文件大小
 * @Date: 2019-07-08 10:11
 * @Version: V2.0
 **/
public class GetFileSize {

    public static void main(String[] args) {

        List<Bean> data = new ArrayList<Bean>();
        //输入一个路径
        String path="G:\\temp";
        getFile(data, path);
        save(data);
        System.out.println("统计完毕");
    }


    private static void save(List<Bean> data) {
        OutputStream os = null;
        OutputStreamWriter osw = null;
        try {
            //将统计的数据大小统计为文件     路径
            os = new FileOutputStream(new File("C:\\Users\\admin\\Desktop\\d1.csv"));
            osw = new OutputStreamWriter(os, "GBK");
            for (Bean bean : data) {
                osw.write(bean + "\r\n");
            }
            osw.flush();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (os != null) {
                try {
                    os.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            if (osw != null) {
                try {
                    osw.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private static void getFile(List<Bean> data, String path) {

        File f = new File(path);
        File[] fs = f.listFiles();

        if (fs == null) {
            return;
        }
        for (File file : fs) {
            //将统计的文件的字节数(单位：B)    方便计算大小
            if (file.isFile()) {
                //getFileSize(file)返回的int最大显示2G
                //System.out.println("文件名："+ file.getName()+",文件大小是："+ getFileSize(file));
                //file.length()可显示完整大小
                System.out.println("文件名："+ file.getName()+",文件大小是："+ file.length());
                data.add(new Bean(file.getParentFile().getAbsolutePath(), file.getName(), (file.length())));
            } else {
                getFile(data, file.getAbsolutePath());
            }
        }
    }

    private static int getFileSize(File f) {
        InputStream fis = null;
        try {
            fis = new FileInputStream(f);
            int docsize=fis.available();
            return docsize;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fis != null) {
                try {
                    fis.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
        return 0;
    }

}

@Data
class Bean {
    private String filePath;
    private String fileName;
    private long size;

    public Bean(String filePath, String fileName, long size) {
        this.filePath = filePath;
        this.fileName = fileName;
        this.size = size;
    }
}

方法二：

        FileChannel fc= null;
        try {
            File f= new File("G:\\temp\\Stanford.zip");
            if (f.exists() && f.isFile()){
                FileInputStream fis= new FileInputStream(f);
                fc= fis.getChannel();
                System.out.println(fc.size());
            }else{
                System.out.println("file doesn't exist or is not a file");
            }
        } catch (FileNotFoundException e) {
            System.out.println(e);
        } catch (IOException e) {
            System.err.println(e);
        } finally {
            if (null!=fc){
                try{
                    fc.close();
                }catch(IOException e){
                    System.err.println(e);
                }
            }
        }

参考连接：1、https://www.cnblogs.com/woshuaile/p/8405261.html

2、https://blog.csdn.net/chaijunkun/article/details/22387305