private void preProPreviousUrl() {// ˴Ҫurlһϴ
		previousHmParameters = null;
		// urlָҳҳ
		String tmpUrl[] = previousUrl.split(s_page_query);
		previousPage = "";
		previousParameter = "";
		previousHmParameters = new HashMap<String, String>();// ѯΪ
		if (tmpUrl.length >= 1) {
			previousPage = tmpUrl[0];
			Matcher m = m_page.matcher(previousPage);
			if (m.find()) {
				previousPage = m.group(1);
			} else {
				previousPage = "";
			}
		}
		if (tmpUrl.length >= 2) {
			previousParameter = tmpUrl[1];
			// ŵhashmap
			if (!previousParameter.equals("")) {
				previousHmParameters = new HashMap<String, String>();
				Matcher matcher = m_query_fields.matcher(previousParameter);
				while (matcher.find()) {
					previousHmParameters.put(matcher.group(1),
							ClsBase.decodeUrl(matcher.group(2), "gb2312"));
				}
			}
		}

	}