转载MARK一下，百度根据关键字不好搜到，省的下次到处找。

package iqiyi.com.model;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class TestMode {
    public static void main(String[] args) {
        String s = "神秘的海洋出现了一只#话题#海怪阿拉斯加#热门话题#和一艘很诡异##的破船\n";
        System.out.println("例子："+s);
        Pattern pattern = Pattern.compile("#(.*?)#");
        Matcher matcher = pattern.matcher(s);
        while (matcher.find()){
            System.out.println(matcher.group(1));
        }

        System.out.println(s.replaceAll("#(.*?)#",""));
    }
}