正则表达式

java替换字符串中表情

 String str = "暑假放假\uD83C\uDF22后几天学\uD83C\uDFF1校开始学习物理知识并实验，从\uD83C\uDFF4中获得了许多知识\uD83D\uDE00";
        System.out.println(str);
        Pattern emoji = Pattern.compile ("[\ud83c\udc00-\ud83c\udfff]|[\ud83d\udc00-\ud83d\udfff]|[\u2600-\u27ff]",Pattern.UNICODE_CASE | Pattern . CASE_INSENSITIVE );
        Matcher emojiMatcher = emoji.matcher(str);
        String s = emojiMatcher.replaceAll("www.baidu.com");
        System.out.println(s);

正则在线验证

https://regex101.com/