Java - NumberFormat 成功解析无效字符串

Question

我正在尝试检查用户是否以有效格式输入了数字。但似乎无效的字符串也被成功解析。一个例子:

final String value1 = "12,85", value2 = "128,598.77";
NumberFormat format = NumberFormat.getInstance(Locale.GERMAN);
format.parse(value1); // ok
format.parse(value2); // ok, but it's not german format

为什么 format.parse(value2) 不抛出异常？

Answer 1

取自java API

public abstract Number parse(String source, ParsePositionparsePosition)

Returns a Long if possible (e.g., within the range [Long.MIN_VALUE,Long.MAX_VALUE] and with no decimals), otherwise a Double. IfIntegerOnly is set, will stop at a decimal point (or equivalent; e.g.,for rational numbers "1 2/3", will stop after the 1). Does not throwan exception; if no object can be parsed, index is unchanged!

这是预期行为，结果将为 128.598