How to remove bad characters that are not suitable for utf8 encoding in MySQL?

Question

I have dirty data. Sometimes it contains characters like this. I use this data to make queries like

WHERE a.address IN (\'mydatahere\')

For

Answer 1

May be this will help someone as it helped me.

public static String removeBadChars(String s) {
  if (s == null) return null;
  StringBuilder sb = new StringBuilder();
  for(int i=0;i