使用HttpClient获取网页字符编码

/**
     * 正则匹配
     * @param s
     * @param pattern
     * @return
     */
    public boolean matcher(String s, String pattern)
{
        Pattern p = Pattern.compile(pattern, Pattern.CASE_INSENSITIVE
                + Pattern.UNICODE_CASE);
        Matcher matcher = p.matcher(s);
        if (matcher.find())
{
            return true;
        } else
{
            return false;
        }
    }
    /**
     * 获取Response内容字符集
     * @param response
     * @return
     */
    public String getContentCharset(HttpResponse response)
{
        String charset = "ISO_8859-1";
        Header header = response.getEntity().getContentType();
        if (header != null)
{
            String s = header.getValue();
            if (matcher(s, "(charset)\\s?=\\s?(utf-?8)"))
{
                charset = "utf-8";
            } else if (matcher(s, "(charset)\\s?=\\s?(gbk)"))
{
                charset = "gbk";
            } else if (matcher(s, "(charset)\\s?=\\s?(gb2312)"))
{
                charset = "gb2312";
            }
        }
        return charset;

    }