java字符串忽略大小写比较 java字符串忽略大小写替换

private static String ReplaceEx(String original, String pattern, String replacement)
 {
     int count, position0, position1;
     count = position0 = position1 = 0;
     String upperString = original.toUpperCase();
     String upperPattern = pattern.toUpperCase();
     int inc = (original.length()/pattern.length())*(replacement.length()-pattern.length());
     char [] chars = new char[original.length() + Math.max(0, inc)];
     while( (position1 = upperString.indexOf(upperPattern, position0)) != -1 )
     {
         for ( int i=position0 ; i < position1 ; ++i ) chars[count++] = original.charAt(i);
         for ( int i=0 ; i < replacement.length() ; ++i ) chars[count++] = replacement.charAt(i);
         position0 = position1+pattern.length();
     }
     if ( position0 == 0 ) return original;
     for ( int i=position0 ; i < original.length() ; ++i ) chars[count++] = original.charAt(i);
     return new String(chars, 0, count);
 }