1.工具類

package cn.cmodes.common.utils;
import java.io.File;
import java.io.FileInputStream;
import java.text.DecimalFormat;

public class FileSizeUtil {
    private static final String TAG=FileSizeUtil.class.getSimpleName();

    public static final int SIZETYPE_B = 1;//獲取文件大小單位為B的double值
    public
 
 static final int SIZETYPE_KB = 2;//獲取文件大小單位為KB的double值
    public static final int SIZETYPE_MB = 3;//獲取文件大小單位為MB的double值
    public static final int SIZETYPE_GB = 4;//獲取文件大小單位為GB的double值

    /**
     * 獲取文件指定文件的指定單位的大小
     *
     * @param filePath 文件路徑
     * @param sizeType 獲取大小的類型1為B、2為KB、3為MB、4為GB
     * @return double值的大小
     
 
*/
    public static double getFileOrFilesSize(String filePath, int sizeType) {
        File file = new File(filePath);
        long blockSize = 0;
        try {
            if (file.isDirectory()) {
                blockSize = getFileSizes(file);
            } else {
                blockSize 
 
= getFileSize(file);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return FormetFileSize(blockSize, sizeType);
    }

    /**
     * 調用此方法自動計算指定文件或指定文件夾的大小
     *
     * @param filePath 文件路徑
     * @return 計算好的帶B、KB、MB、GB的字符串
     */
    public static String getAutoFileOrFilesSize(String filePath) {
        File file = new File(filePath);
        long blockSize = 0;
        try {
            if (file.isDirectory()) {
                blockSize = getFileSizes(file);
            } else {
                blockSize = getFileSize(file);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return formatFileSize(blockSize);
    }

    /**
     * 獲取指定文件大小
     */
    private static long getFileSize(File file) throws Exception {
        long size = 0;
        if (file.exists()) {
            FileInputStream fis = null;
            fis = new FileInputStream(file);
            size = fis.available();
        } else {
            file.createNewFile();
        }
        return size;
    }

    /**
     * 獲取指定文件夾
     */
    private static long getFileSizes(File f) throws Exception {
        long size = 0;
        File flist[] = f.listFiles();
        assert flist != null;
        for (File file : flist) {
            if (file.isDirectory()) {
                size = size + getFileSizes(file);
            } else {
                size = size + getFileSize(file);
            }
        }
        return size;
    }

    /**
     * 轉換文件大小
     */
    public static String formatFileSize(long fileS) {
        DecimalFormat df = new DecimalFormat("#.00");
        String fileSizeString = "";
        String wrongSize = "0B";
        if (fileS == 0) {
            return wrongSize;
        }
        if (fileS < 1024) {
            fileSizeString = df.format((double) fileS) + "B";
        } else if (fileS < 1048576) {
            fileSizeString = df.format((double) fileS / 1024) + "KB";
        } else if (fileS < 1073741824) {
            fileSizeString = df.format((double) fileS / 1048576) + "MB";
        } else {
            fileSizeString = df.format((double) fileS / 1073741824) + "GB";
        }
        return fileSizeString;
    }

    /**
     * 轉換文件大小,指定轉換的類型
     */
    private static double FormetFileSize(long fileS, int sizeType) {
        DecimalFormat df = new DecimalFormat("#.00");
        double fileSizeLong = 0;
        switch (sizeType) {
            case SIZETYPE_B:
                fileSizeLong = Double.valueOf(df.format((double) fileS));
                break;
            case SIZETYPE_KB:
                fileSizeLong = Double.valueOf(df.format((double) fileS / 1024));
                break;
            case SIZETYPE_MB:
                fileSizeLong = Double.valueOf(df.format((double) fileS / 1048576));
                break;
            case SIZETYPE_GB:
                fileSizeLong = Double.valueOf(df.format((double) fileS / 1073741824));
                break;
            default:
                break;
        }
        return fileSizeLong;
    }
}

2.使用

    /**
     * 新增多媒體-圖片
     *
     * @param mediaphoto 多媒體-圖片信息
     * @return 結果
     */
    @Override
    @Transactional
    public int insertMediaphoto(Mediaphoto mediaphoto) {
        if (StringUtils.isBlank(mediaphoto.getId())) {
            mediaphoto.setId(IdGen.uuid());
        }
        mediaphoto.setCreateTime(new Date());
        mediaphoto.setFileSize(fileService.formatFileSize(mediaphoto.getFileName()));
        int i = mediaphotoMapper.insertMediaphoto(mediaphoto);
        searchService.UpdateResourceEs(mediaphoto.getDocumentId());
        return i;
    }

3.效果圖

java 上傳文件大小轉換為 GB/MB/KB/B