Java 十进制格式解析问题 [英] Java Decimal Format parsing issue

问题描述

public class NumFormatTest
{
    public static void main(String[] args) throws ParseException 
    {
        String num = "1 201";
        DecimalFormat df = (DecimalFormat) NumberFormat.getNumberInstance(Locale.FRANCE);
        System.out.println("Number Before parse: "+num);        
        double  dm = df.parse(num).doubleValue();
        System.out.println("Number After parse: "+dm);  
    }
}

输出:

 Number Before parse: 1 201

 Number After parse: 1.0

预期输出:

  Number Before parse: 1 201

  Number After parse: **1201**

谁能帮我理解为什么 parse 无法将 FRENCH 语言环境格式的字符串 (1 201) 转换为正常的双精度值 (1201.0)?

Can any please help me understand why parse is not able to convert a FRENCH locale formatted string (1 201) to normal double value (1201.0)?

推荐答案

有两种空格.正常"空格字符(No. 32 - HEX 0x20)和不间断空格(NBSP)(No. 160 - HEX 0xA0).

There are two kinds of spaces. The "normal" space character (No. 32 - HEX 0x20) and the non-breaking space (NBSP) (No. 160 - HEX 0xA0).

法语语言环境要求数字之间的空白字符是不间断空格！你可以用这行代码来帮助自己:

The French locale expects the whitespace character between the digits to be the non breaking space! You can help yourself with this line of code:

String num = "1 201";
num = num.replaceAll(" ", "\u00A0");    // '\u00A0' is the non breaking whitespace character!

这样你的代码就会像预期的那样工作.请注意，如果您将 double 格式化为具有法语语言环境的 String，则生成的空白字符也将是 NBSP！！！

This way your code will work like expected. Please note that if you format a double into a String with French locale the resulting whitespace character will be the NBSP too!!!

DecimalFormat df = (DecimalFormat) NumberFormat.getNumberInstance(Locale.FRENCH);
System.out.println(df.format(1201.1));
// This will print "1 202,1" But the space character will be '\u00A0'!

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