Spring Security3.0怎么用js获得是否已经登录了而且获得登录数据

Question

  Level: DEBUG
   Time: 2011-01-29 20:46:38,140
 Method: org.springframework.security.access.intercept.AbstractSecurityInterceptor.authenticateIfRequired(AbstractSecurityInterceptor.java:292)
Message: Previously Authenticated: org.springframework.security.authentication.UsernamePasswordAuthenticationToken@65acf777: Principal: org.springframework.security.core.userdetails.User@0: Username: admin; Password: [PROTECTED]; Enabled: true; AccountNonExpired: true; credentialsNonExpired: true; AccountNonLocked: true; Granted Authorities: Admin_role; Password: [PROTECTED]; Authenticated: true; Details: org.springframework.security.web.authentication.WebAuthenticationDetails@1c07a: RemoteIpAddress: 127.0.0.1; SessionId: 4DA3893BAD3E43930D5FDCDF790E763C; Granted Authorities: Admin_role
Object:FilterInvocation: URL: //index.jsp我用log4j记录日志文件的时候发现security中可以获得IP而且我想做个用js判断是不是已经登录了！问下大家这个该怎么弄？
能不能讲详细点。

Answer 1

如果写java代码的话这个就可以、、、
                // 获得上下文
SecurityContext secCtx = SecurityContextHolder.getContext();
// 获取认证对象
Authentication auth = secCtx.getAuthentication();
// 在认证对象中获取主体对象
SSUsers user = (SSUsers) auth.getPrincipal();