将Unicode转换为UTF-8字节[]并保存为字符串（Java）

Question

I need to convert the character unicode to a byte[] representation and save into Srting, for example

U+1F601 -> \xF0\x9F\x98\x81

I dont have idea how can i do it this.. Anyone has idea?Thanks

Answer 1

int[] codepoints = { 0x1F601 }; // U+1F601
String s = new String(codepoints, 0, codepoints.length);
byte[] bytes = s.getBytes(StandardCharsets.UTF_8); // As UTF-8 (Unicode) bytes
System.out.println(Arrays.toString(bytes));

So one first coposes the Unicode code points into a java String. Java Strings hold Unicode. When one wants bytes, say in UTF-8 - a Unicode representation -, then one has to indicate the CharSet in which the bytes will be.