如何获取mb中的文件大小？

Question

我在服务器上有一个文件,它是一个zip文件.如何检查文件大小是否大于27 MB？

File file = new File("U:\intranet_root\intranet\R1112B2.zip");
if (file > 27) {
   //do something
}

Answer 1

使用类的length()方法File以字节为单位返回文件的大小.

// Get file from file name
File file = new File("U:\intranet_root\intranet\R1112B2.zip");

// Get length of file in bytes
long fileSizeInBytes = file.length();
// Convert the bytes to Kilobytes (1 KB = 1024 Bytes)
long fileSizeInKB = fileSizeInBytes / 1024;
// Convert the KB to MegaBytes (1 MB = 1024 KBytes)
long fileSizeInMB = fileSizeInKB / 1024;

if (fileSizeInMB > 27) {
  ...
}

您可以将转换合并为一个步骤,但我已尝试完全说明该过程.

Answer 2

请尝试以下代码:

File file = new File("infilename");

// Get the number of bytes in the file
long sizeInBytes = file.length();
//transform in MB
long sizeInMb = sizeInBytes / (1024 * 1024);

Answer 3

示例:

public static String getStringSizeLengthFile(long size) {

    DecimalFormat df = new DecimalFormat("0.00");

    float sizeKb = 1024.0f;
    float sizeMb = sizeKb * sizeKb;
    float sizeGb = sizeMb * sizeKb;
    float sizeTerra = sizeGb * sizeKb;


    if(size < sizeMb)
        return df.format(size / sizeKb)+ " Kb";
    else if(size < sizeGb)
        return df.format(size / sizeMb) + " Mb";
    else if(size < sizeTerra)
        return df.format(size / sizeGb) + " Gb";

    return "";
}

Answer 4

最简单的方法是使用Apache commons-io中的FileUtils.(https://commons.apache.org/proper/commons-io/javadocs/api-2.5/org/apache/commons/io/FileUtils.html)

返回人类可读的文件大小,从Bytes到Exabytes,向下舍入到边界.

File fileObj = new File(filePathString);
String fileSizeReadable = FileUtils.byteCountToDisplaySize(fileObj.length());

// output will be like 56 MB 

Answer 5

file.length()将返回以字节为单位的长度,然后将其除以1048576,现在你已经有了兆字节!