java - 了解 java 字符串中包含的文本是否包含 UTF-8 编码字符的最佳方法

Question

有没有其他方法可以知道 java String 是否包含 UTF-8 中的 character-encoding编码与否，例如阿拉伯语单词。

我试过这段代码:但它是否准确并能胜任工作？

char c = 'أ';
int num = (int) c;

if(num> 128)
// then UTF-8 characters exists 

Answer 1

(假设 UTF-8 == 非 ASCII)

您可以做的是编码然后解码 ASCII 中的字符串，并将结果与​​原始结果进行比较。如果它们不相等，则存在非 ASCII 字符。

但是，您自己的样本也可以工作(几乎应该是 >= 128 )，因为以下证明确实所有 char s < 128是 ASCII:

To allow backward compatibility, the 128 ASCII and 256 ISO-8859-1 (Latin 1) characters are assigned Unicode/UCS code points that are the same as their codes in the earlier standards.

The first plane (code points U+0000 to U+FFFF) contains the most frequently used characters and is called the Basic Multilingual Plane or BMP. Both UTF-16 and UCS-2 encode valid code points in this range as single 16-bit code units that are numerically equal to the corresponding code points.

(“UTF-16”和“ASCII”，维基百科)

和char s 是 UTF-16“代码单元”。

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但是，从整个问题来看，您最好还是阅读 The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!)首先。