Java 读取带有补充 unicode 字符的字符流
我在使用 Java 读取补充 unicode 字符时遇到问题。我有一个文件可能包含补充集中的字符（任何大于 \uFFFF 的字符）。当我设置 InputStreamReader 使用 UTF-8 读取文件时，我希望 read() 方法为每个补充字符返回单个字符，而不是它似乎在 16 位阈值上分割。
我看到了一些有关基本 unicode 字符流的其他问题，但似乎没有任何内容可以处理大于 16 位的情况。
下面是一些简化的示例代码：
InputStreamReader input = new InputStreamReader(file, "UTF8");
int nextChar = input.read();
while(nextChar != -1) {
...
nextChar = input.read();
}
有谁知道我需要做什么才能正确读取包含增补字符的 UTF-8 编码文件？
I'm having trouble reading in supplementary unicode characters using Java. I have a file that potentially contains characters in the supplementary set (anything greater than \uFFFF). When I setup my InputStreamReader to read the file using UTF-8 I would expect the read() method to return a single character for each supplementary character, instead it seems to split on the 16 bit threshold.
I saw some other questions about basic unicode character streams, but nothing seems to deal with the greater than 16 bit case.
Here's some simplified sample code:
InputStreamReader input = new InputStreamReader(file, "UTF8");
int nextChar = input.read();
while(nextChar != -1) {
...
nextChar = input.read();
}
Does anyone know what I need to do to correctly read in a UTF-8 encoded file that contains supplementary characters?
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（2）
Java 使用 UTF-16。因此，如果您的输入流有星体字符，它们将显示为代理对，即两个
char。第一个字符是高代理项，第二个字符是低代理项。Java works with UTF-16. So, if your input stream has astral characters, they will appear as a surrogate pair, i.e., as two
chars. The first character is the high surrogate, and the second character is the low surrogate.虽然
read()被定义为返回int，并且理论上可以“一次”返回补充字符的代码点，但我相信返回类型只是int允许返回值-1。从
read()获得的值基本上是另一个名称的char，而 Javachar仅限于 16 位。Java 只能将增补字符表示为 UTF-16 代理对，一旦超过 0xFFFF，就不存在“单个字符”（至少在
char意义上）了。担心的。Though
read()is defined to returnint, and could theoretically return a supplementary character's code point "all at once", I believe the return type is onlyintto allow a value of -1 to be returned.The value you're getting from
read()is basically acharby another name, and Java acharis limited to 16 bits.Java can only represent supplementary characters as a UTF-16 surrogate pair, there is no such thing as a "single character" (at least in the
charsense) once you get above 0xFFFF as far as Java is concerned.