java 返回文件大小（带单位）

print sizes in human readable format (e.g., 1K 234M 2G)

 

java File.java类中的length()方法返回的文件长度是长以字节为单位，下面的方法是根据字节数格式化相应的其他单位(KB、MB、GB等)。

 

public static String getFormatSize(double size) {
		double kiloByte = size/1024;
		if(kiloByte < 1) {
			return size + "Byte(s)";
		}
		
		double megaByte = kiloByte/1024;
		if(megaByte < 1) {
			BigDecimal result1 = new BigDecimal(Double.toString(kiloByte));
			return result1.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "KB";
		}
		
		double gigaByte = megaByte/1024;
		if(gigaByte < 1) {
			BigDecimal result2  = new BigDecimal(Double.toString(megaByte));
			return result2.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "MB";
		}
		
		double teraBytes = gigaByte/1024;
		if(teraBytes < 1) {
			BigDecimal result3 = new BigDecimal(Double.toString(gigaByte));
			return result3.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "GB";
		}
		BigDecimal result4 = new BigDecimal(teraBytes);
		return result4.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "TB";
	}