Long.parseLong（“+ 2013”​​）抛出NumberFormatException

Question

我正在尝试使用外部Java库来处理Android，但是在处理日期时它会抛出错误。

我把它缩小到这条线：

Long year = Long.parseLong("+2013");

抛出一个

Caused by: java.lang.NumberFormatException: Invalid long: "+2013"

但是，代码有效并且在纯Java应用程序中工作。为什么Long.parseLong()在Android应用中的工作方式不同？

Android's documentation声明'+'Ascii标志得到承认：

public static long parseLong (String string)

     

将指定的字符串解析为带符号的十进制长值。 ASCII字符 - （' - '）和+（'+'）被识别为减号和加号。

Answer 1

谢谢大家！管理以找出问题。

似乎API 17：Android 4.2（Jelly Bean）正在引发问题。 API无法正确处理parseLong（）中的“+”符号。

解决了它将编译SDK更改为API 21及更高版本的问题。

API 20 parseLong（）

    /**
 * Parses the specified string as a signed long value using the specified
 * radix. The ASCII character \u002d ('-') is recognized as the minus sign.
 *
 * @param string
 *            the string representation of a long value.
 * @param radix
 *            the radix to use when parsing.
 * @return the primitive long value represented by {@code string} using
 *         {@code radix}.
 * @throws NumberFormatException
 *             if {@code string} cannot be parsed as a long value, or
 *             {@code radix < Character.MIN_RADIX ||
 *             radix > Character.MAX_RADIX}.
 */
public static long parseLong(String string, int radix) throws NumberFormatException {
    if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) {
        throw new NumberFormatException("Invalid radix: " + radix);
    }
    if (string == null) {
        throw invalidLong(string);
    }
    int length = string.length(), i = 0;
    if (length == 0) {
        throw invalidLong(string);
    }
    boolean negative = string.charAt(i) == '-';
    if (negative && ++i == length) {
        throw invalidLong(string);
    }

    return parse(string, i, radix, negative);
}

API 21 parseLong（）

    /**
 * Parses the specified string as a signed long value using the specified
 * radix. The ASCII characters \u002d ('-') and \u002b ('+') are recognized
 * as the minus and plus signs.
 *
 * @param string
 *            the string representation of a long value.
 * @param radix
 *            the radix to use when parsing.
 * @return the primitive long value represented by {@code string} using
 *         {@code radix}.
 * @throws NumberFormatException
 *             if {@code string} cannot be parsed as a long value, or
 *             {@code radix < Character.MIN_RADIX ||
 *             radix > Character.MAX_RADIX}.
 */
public static long parseLong(String string, int radix) throws NumberFormatException {
    if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) {
        throw new NumberFormatException("Invalid radix: " + radix);
    }
    if (string == null || string.isEmpty()) {
        throw invalidLong(string);
    }
    char firstChar = string.charAt(0);
    int firstDigitIndex = (firstChar == '-' || firstChar == '+') ? 1 : 0;
    if (firstDigitIndex == string.length()) {
        throw invalidLong(string);
    }

    return parse(string, firstDigitIndex, radix, firstChar == '-');
}