使用ThreadLocal保存用户登录信息实例代码介绍。

最近在使用WebSocket来进行消息推送，一，系统推送。二，用户对用户进行推送。
SystemSession类：
[java]view plaincopyprint?在CODE上查看代码片派生到我的代码片
import com.srkj.code.model.User;
/**
* 线程共享类
* @author 胡汉三
*
* 2014-11-18 下午2:40:27
*/
public class SystemSession {
//声明
private static ThreadLocal<User> local = new ThreadLocal<User>();
/**
* 赋值
* @param session
*/
public static void set(User session) {
local.set(session);
}
/**
* 取值
* @return
*/
public static User get() {
return local.get();
}
/**
* 移除
*/
public static void remove(){
local.remove();
}
}
使用过滤器拦截用户请求：
[java]view plaincopyprint?在CODE上查看代码片派生到我的代码片
import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

import com.srkj.code.model.User;
/**
* Session过滤器
* @author 胡汉三
*
* 2014-11-18 下午2:41:35
*/
public class MyFilter implements Filter{

public void destroy() {}

public void doFilter(ServletRequest req, ServletResponse res,
FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest)req;
User userSession = (User)request.getSession().getAttribute(“userInfo”);
if (userSession != null) {
//重新设值session
request.getSession().setAttribute(“userInfo”, userSession);
}
filterChain.doFilter(req, res);

}

public void init(FilterConfig arg0) throws ServletException {}

}
web.xml配置：
[html]view plaincopyprint?在CODE上查看代码片派生到我的代码片
<filter>
<filter-name>myFilter</filter-name>
<filter-class>com.srkj.code.util.MyFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>myFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
在配置一个用户session状态变更的监听类MyHttpSessionAttributeListener：
[java]view plaincopyprint?在CODE上查看代码片派生到我的代码片
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;

import com.srkj.code.model.User;
/**
* Session监听器
* @author 胡汉三
*
* 2014-11-18 下午2:42:02
*/
public class MyHttpSessionAttributeListener implements HttpSessionAttributeListener {
/**
* 添加Session
*/
public void attributeAdded(HttpSessionBindingEvent event) {
if (“userInfo”.equals(event.getName())) {
SystemSession.set((User)event.getValue());
}
}

/**
* 替代Session
*/
public void attributeReplaced(HttpSessionBindingEvent event) {
if (“userInfo”.equals(event.getName())) {
SystemSession.set((User)event.getValue());
}
}

/**
* 销毁Session
*/
public void attributeRemoved(HttpSessionBindingEvent event) {
if(“userInfo”.equals(event.getName())){
SystemSession.remove();
}
}
}
web.xml监听配置：
[html]view plaincopyprint?在CODE上查看代码片派生到我的代码片
<listener>
<listener-class>com.srkj.code.util.MyHttpSessionAttributeListener</listener-class>
</listener>
这样之后，就可以在程序中直接SystemSession.get() 就能得到用户对象，如：
[java]view plaincopyprint?在CODE上查看代码片派生到我的代码片
public ChatAnnotation() {
nickname = SystemSession.get().getUuuid();
}