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

1. public class CSession { 
2.     private String username; 
3.     private String userId; 
4.          
5.     public String getUsername() { 
6.         return username; 
7.     } 
8.     public void setUsername(String username) { 
9.         this.username = username; 
10.     } 
11.      
12.     public String getUserId() { 
13.         return userId; 
14.     } 
15.     public void setUserId(String userId) { 
16.         this.userId = userId; 
17.     } 
18. } 

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

1. public class SessionUser { 
2.  
3.  
4.     @SuppressWarnings("unchecked") 
5.     static ThreadLocal sessionUser = new ThreadLocal(); 
6.      
7.     @SuppressWarnings("unchecked") 
8.     public static void setSessionUser(CSession cSession) { 
9.         sessionUser.set(cSession); 
10.     } 
11.      
12.     public static CSession getSessionUser(){ 
13.         return (CSession )sessionUser.get(); 
14.     } 
15.      
16.     public static String getSessionUserId(){ 
17.         return getSessionUser().getUserId(); 
18.     } 
19.      
20.     public static String getSessionUserName(){ 
21.         return getSessionUser().getUsername(); 
22.     } 
23. } 

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

1. HttpSession session = request.getSession(true); 
2. CSession cs = new CSession(); 
3. cs.setUserId(userId); 
4. cs.setUsername(userName); 
5. 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

1. public void doFilter(ServletRequest request, ServletResponse response, 
2.             FilterChain chain) throws IOException, ServletException { 
3.          
4.         HttpServletRequest hrequest = (HttpServletRequest) request; 
5.         HttpServletResponse hresponse = (HttpServletResponse) response; 
6.          
7.                ....... 
8.          
9.         CSession cs = (CSession) hrequest.getSession(true).getAttribute("C_SESSION"); 
10.          
11.         SessionUser.setSessionUser(cs); 
12.                          
13.                 ....... 
14.     } 

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

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

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

页面上，

Java代码

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