泛型编程实例之（二）

基本泛型类：

 

public abstract class SessionServiceBase<T> {

	public abstract String getStringFromEntry(T entry);
       
    	/**
	 * 存储介质的存储string，比如cookie里、threadlocal里等
	 * 
	 * @param value
	 * @param seconds
	 */
	public abstract void setString(String value, int seconds);

	public void set(T entry) {
		// 写入cookie
		set(entry, 3600 * 24 * 30); // 默认30天
	}

	public final void set(T entry, int seconds) {
		String value = getStringFromEntryInternal(entry);
		setString(value, seconds);
	}

	String getStringFromEntryInternal(T entry) {
		String s = getStringFromEntry(entry);

		return StringUtil.signContent(s, getSalt());
	}
}

 抽象泛型类的实现类：

public class CookieSessionService extends SessionServiceBase<User> {
	private tools.web.CookieUtil cookie = null;
。。。
	@Override
	public void setString(String arg0, int arg1) {
		try {
			cookie.set(name, URLEncoder.encode(arg0, ENCODING), domain, null,
					arg1);
		} catch (UnsupportedEncodingException e) {
		}
	}

}

 

调用它的类：

public class Request extends HttpServlet {

	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		long startTime = System.currentTimeMillis();
		request.setCharacterEncoding("GBK");

		String action = request.getParameter("action");
    ....
		if ("auth".equalsIgnoreCase(action)) {
			auth(request, response);
			return;
  ....
	private void auth(HttpServletRequest request, HttpServletResponse response) {
		String name = request.getParameter("name");

		CookieSessionService cs = CookieSessionService.create(request,
				response, "auth", null);
		User u = new User();
		u.setUserId(0);
		u.setUserName(name);
		u.setData(request.getParameter("data"));

		cs.set(u);
	}

}