DAO层和Service层访问session

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

Java代码




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;

}
}

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

Java代码




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();

}
}

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，

Java代码




HttpSession session = request.getSession(true);

CSession cs = new CSession();

cs.setUserId(userId);
cs.setUsername(userName);
session.setAttribute("C_SESSION",cs);

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，

Java代码




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);

.......
}

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,

Java代码




xxxTO.setUserId(SessionUser.getSessionUserId()); xxxTO.setUserName(SessionUser.getSessionUserName());

xxxTO.setUserId(SessionUser.getSessionUserId());
xxxTO.setUserName(SessionUser.getSessionUserName());

页面上，

Java代码




<bean:write name="C_SESSION" property="username"/>

<bean:write name="C_SESSION" property="userId"/>

<bean:write name="C_SESSION" property="username"/>
<bean:write name="C_SESSION" property="userId"/>