Java-使用单个表情符号读取UTF-8文件
问题描述：
我有一个带有单个unicode符号的文件.
该文件以UTF-8编码.
它包含一个表示为4个字节的符号.
https://www.fileformat.info/info/unicode/char/1f60a/index.htm
I have a file with a single unicode symbol.
The file is encoded in UTF-8.
It contains a single symbol represented as 4 bytes.
https://www.fileformat.info/info/unicode/char/1f60a/index.htm
F0 9F 98 8A
当我读取文件时，我得到两个符号/字符.
When I read the file I get two symbols/chars.
下面的程序打印
?
2
?
?
55357
56842
======================================
��
16
&
======================================
?
2
?
======================================
这是正常现象还是错误?还是我在滥用某些东西?
如何在代码中获取单个表情符号?
Is this normal... or a bug? Or am I misusing something?
How do I get that single emoji symbol in my code?
而且...如何将其转义为XML?
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
public class Test008 {
public static void main(String[] args) throws Exception{
BufferedReader in = new BufferedReader(
new InputStreamReader(
new FileInputStream("D:\\DATA\\test1.txt"), "UTF8"));
String s = "";
while ((s = in.readLine()) != null) {
System.out.println(s);
System.out.println(s.length());
System.out.println(s.charAt(0));
System.out.println(s.charAt(1));
System.out.println((int)(s.charAt(0)));
System.out.println((int)(s.charAt(1)));
String z = org.apache.commons.lang.StringEscapeUtils.escapeXml(s);
String z3 = org.apache.commons.lang3.StringEscapeUtils.escapeXml(s);
System.out.println("======================================");
System.out.println(z);
System.out.println(z.length());
System.out.println(z.charAt(0));
System.out.println("======================================");
System.out.println(z3);
System.out.println(z3.length());
System.out.println(z3.charAt(0));
System.out.println("======================================");
}
in.close();
}
}
答
是的，Unicode符号为2个UTF-16字符(1个字符为2个字节).
Yes normal, the Unicode symbol is 2 UTF-16 chars (1 char is 2 bytes).
int codePoint = s.codePointAt(0); // Your code point.
System.out.printf("U+%04X, chars: $d%n", codePoint, Character.charCount(cp));
U+F09F988A, chars: 2
评论后
After comments
Java，使用流:
public static String escapeToAsciiHTML(String s) {
StringBuilder sb = new StringBuilder();
s.codePoints().forEach(cp -> {
if (cp < 128) {
sb.append((char) cp);
} else{
sb.append("&#").append(cp).append(";");
}
});
return sb.toString();
}