java中如何检测一个字符串是否包含指定“不区分大小写的字符”呢？

实现思路：
  1.借助 org.apache.commons.lang3.StringUtils.containsIgnoreCase(CharSequence str,
                                     CharSequence searchStr); 
  2.使用正则表达式进行判断
    public boolean regionMatches(boolean ignoreCase,
                             int toffset,
                             String other,
                             int ooffset,
                             int len)
	ignoreCase:true 则代表比较字符时，忽略大小写

public static boolean containsIgnoreCase(String str, String searchStr)     {
    if(str == null || searchStr == null) return false;

    final int length = searchStr.length();
    if (length == 0)
        return true;

    for (int i = str.length() - length; i >= 0; i--) {
        if (str.regionMatches(true, i, searchStr, 0, length))
            return true;
    }
    return false;
}