很多情况下,我们需要在DAO或者Service层拿到Session中的值,比如下面这个应用,session中存放了当前用户的账号,在DAO层中需要insert一条record,这条record需要记录当前用户(该记录是由谁创建的),对于这样的应用,我们一般可以在Action层中通过request拿到session里的用户账号,然后传入service,再传入DAO层,就可以解决了。
今天,我在这里记录一种方式,利用ThreadLocal来存入sesion,然后可以在任何业务层,DAO层获取Session的方式,首先建立一个CSession来存放session的值,只放了2个属性,用户的账号和姓名
public class CSession { private String username; private String userId; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getUserId() { return userId; } public void setUserId(String userId) { this.userId = userId; } }
建立SessionUser类,用来存放在整个运行期CSession的存在
public class SessionUser { @SuppressWarnings("unchecked") static ThreadLocal sessionUser = new ThreadLocal(); @SuppressWarnings("unchecked") public static void setSessionUser(CSession cSession) { sessionUser.set(cSession); } public static CSession getSessionUser(){ return (CSession )sessionUser.get(); } public static String getSessionUserId(){ return getSessionUser().getUserId(); } public static String getSessionUserName(){ return getSessionUser().getUsername(); } }
在登录的Action里,登录成功后,加Session里的用户信息,放入CSession中,
HttpSession session = request.getSession(true); CSession cs = new CSession(); cs.setUserId(userId); cs.setUsername(userName); session.setAttribute("C_SESSION",cs);
最后,在session check的Filter中,把CSession注入到SessionUser中,
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest hrequest = (HttpServletRequest) request; HttpServletResponse hresponse = (HttpServletResponse) response; ....... CSession cs = (CSession) hrequest.getSession(true).getAttribute("C_SESSION"); SessionUser.setSessionUser(cs); ....... }
下面我们就可以再DAO层中直接从SessionUser中获取 userid 和 username,
xxxTO.setUserId(SessionUser.getSessionUserId()); xxxTO.setUserName(SessionUser.getSessionUserName());
页面上,
<bean:write name="C_SESSION" property="username"/> <bean:write name="C_SESSION" property="userId"/>