java 倍数
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Double to Number
提问by ajjukhot
How to convert Double to Number in Java, like in the code below?
如何在 Java 中将 Double 转换为 Number，如下面的代码所示？
public Number parse(String text, ParsePosition status) {
// find the best number (defined as the one with the longest parse)
int start = status.index;
int furthest = start;
double bestNumber = Double.NaN;
double tempNumber = 0.0;
for (int i = 0; i < choiceFormats.length; ++i) {
String tempString = choiceFormats[i];
if (Misc.regionMatches(start, tempString, 0, tempString.length(), text)) {
status.index = start + tempString.length();
tempNumber = choiceLimits[i];
if (status.index > furthest) {
furthest = status.index;
bestNumber = tempNumber;
if (furthest == text.length()) break;
}
}
}
status.index = furthest;
if (status.index == start) {
status.errorIndex = furthest;
}
int c= 0;
return new Double(bestNumber);
}
But in Eclipse it shows
但在 Eclipse 中它显示
Type mismatch: cannot convert from Double to Number
Actually this code belongs to ChoiceFormat.javaclass from java.textpackage.
实际上这段代码属于包中的ChoiceFormat.java类java.text。
回答by NINCOMPOOP
java.lang.Doubleis a subclass of java.lang.Number. Hence the posted code shouldn't show any compilation error if you are returning a java.lang.Doublefrom a method which returns java.lang.Number.
java.lang.Double的是子类java.lang.Number中。因此，如果您java.lang.Double从返回java.lang.Number.
As Jon Skeet pointed out, "you've got a different Double type or a different Number type somewhere". Please double check to see if you are using java.lang.Doubleand java.lang.Number.
正如 Jon Skeet 指出的那样，“您在某处拥有不同的 Double 类型或不同的 Number 类型”。请仔细检查您是否正在使用java.lang.Double和java.lang.Number。
回答by Sanjaya Liyanage
Use casting
使用铸造
Double d=new Double(2);
Number n=(Number)d;
in your case
在你的情况下
Double d=new Double(bestNumber);
Number n=(Number)d;
return n;
