把用户登录状态usersessions存贮到redis

登录过期时间设置为7天

src/com/lxyer/bbs/base/BaseService.java

@@ -11,7 +11,7 @@ import java.io.File;
  */
 public class BaseService implements Service {
 
-    protected final int sessionExpireSeconds = 30 * 60;
+    protected final int sessionExpireSeconds = 7 * 24 * 60 * 60;
 
     @Resource(name = "SERVER_ROOT")
     protected File webroot;