Removing special character from Java String

Question

I am trying to work around to remove symbols and special characters from a raw text in java and could not find way around. The text is taken from a free-text field in a website which may contain literally anything. I am taking this text from an external source and have no control to change setting. So I have to work around at my end. Some examples are

1) belem 🐺 should be--> belem

2) Ariana 👑 should be--> Ariana

3) Harlem 🌊 should be--> Harlem

4) Yz 🏳️‍🌈 should be--> Yz

5) ここさけは7回は見に行くぞ👍💟 should be--> ここさけは7回は見に行くぞ

6) دمي ازرق وطني ازرق 💙🔵🔵🔵🔵 should be--> دمي ازرق وطني ازرق

Any help please?

Answer 1

You can try this regex that find all emojis in a string :

regex = "[\\ud83c\\udc00-\\ud83c\\udfff]|[\\ud83d\\udc00-\\ud83d\\udfff]|[\\u2600-\\u27ff]"

then remove all the emojis in it using replaceAll() method:

String text = "ここさけは7回は見に行くぞ👍💟 ";
String regex = "[\\ud83c\\udc00-\\ud83c\\udfff]|[\\ud83d\\udc00-\\ud83d\\udfff]|[\\u2600-\\u27ff]";
System.out.println(text.replaceAll(regex, ""));

Output :

ここさけは7回は見に行くぞ 

Answer 2

If you mean "special characters" are surrogate pairs, try this.

static String removeSpecial(String s) {
    int[] r = s.codePoints()
        .filter(c -> c < Character.MIN_SURROGATE)
        .toArray();
    return new String(r, 0, r.length);
}

and

String[] testStrs = {
    "belem 🐺",
    "Ariana 👑",
    "Harlem 🌊",
    "Yz 🏳️‍🌈",
    "ここさけは7回は見に行くぞ👍💟",
    "دمي ازرق وطني ازرق 💙🔵🔵🔵🔵"
};

for (String s : testStrs)
    System.out.println(removeSpecial(s));

results

belem 
Ariana 
Harlem 
Yz ‍
ここさけは7回は見に行くぞ
دمي ازرق وطني ازرق 

Answer 3

对于空格使用字符类，对“任何语言的任何字母或数字”使用POSIX字符类：

str = str.replaceAll("[^\\s\\p{Alnum}]", "");