Java - 将人类可读大小转换为字节 [英] Java - Convert Human Readable Size to Bytes

问题描述

我发现了很多关于将原始字节信息转换为人类可读格式的信息，但我需要做相反的事情，即将字符串1.6 GB转换为长值1717990000.是否有内置/明确定义的方法，或者我几乎要自己动手？

I've found lots of information about converting raw byte information into a human-readable format, but I need to do the opposite, i.e. convert the String "1.6 GB" into the long value 1717990000. Is there an in-built/well-defined way to do this, or will I pretty much have to roll my own?

：这是我的第一次刺...

: Here is my first stab...

static class ByteFormat extends NumberFormat {
    @Override
    public StringBuffer format(double arg0, StringBuffer arg1, FieldPosition arg2) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public StringBuffer format(long arg0, StringBuffer arg1, FieldPosition arg2) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public Number parse(String arg0, ParsePosition arg1) {
        return parse (arg0);
    }

    @Override
    public Number parse(String arg0) {
        int spaceNdx = arg0.indexOf(" ");
        double ret = Double.parseDouble(arg0.substring(0, spaceNdx));
        String unit = arg0.substring(spaceNdx + 1);
        int factor = 0;
        if (unit.equals("GB")) {
            factor = 1073741824;
        }
        else if (unit.equals("MB")) {
            factor = 1048576;
        }
        else if (unit.equals("KB")) {
            factor = 1024;
        }

        return ret * factor;
    }
}

推荐答案

我从来没有听说过这样一个着名的库，它实现了这种文本解析实用程序方法。但是你的解决方案似乎接近正确的实现。

I've never heard about such well-known library, which implements such text-parsing utility methods. But your solution seems to be near from correct implementation.

我想在你的代码中纠正的唯一两件事是：

The only two things, which I'd like to correct in your code are:

1. 定义方法数字解析（String arg0）由于其实用性而为静态

1. define method Number parse(String arg0) as static due to it utility nature

为每种类型的大小定义定义 factor s为 final static fields。

define factors for each type of size definition as final static fields.

即它将是这样的：

private final static long KB_FACTOR = 1024;
private final static long MB_FACTOR = 1024 * KB_FACTOR;
private final static long GB_FACTOR = 1024 * MB_FACTOR;

public static double parse(String arg0) {
    int spaceNdx = arg0.indexOf(" ");
    double ret = Double.parseDouble(arg0.substring(0, spaceNdx));
    switch (arg0.substring(spaceNdx + 1)) {
        case "GB":
            return ret * GB_FACTOR;
        case "MB":
            return ret * MB_FACTOR;
        case "KB":
            return ret * KB_FACTOR;
    }
    return -1;
}

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