shiro SecurityUtils.getSubject()获取的信息由来

shiro 管理登录，获取登录信息的方式常用的是：

subject sub = SecurityUtils.getSubject();
Object obj = sub.getPrincipal();

这里的 obj 是字符串，还是某个实体，取决于 ShiroRealm 类的设置值，代码如下：

@Overrideprotected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken authenticationToken)throws AuthenticationException {System.out.println("获取登录者信息-->MyShiroRealm.doGetAuthenticationInfo()");UsernamePasswordToken token = (UsernamePasswordToken) authenticationToken;String userS = token.getUsername();User user = userService.findByName(userS);if (user != null) {LoginInfo info = new LoginInfo();info.setName(user.getName());info.setLoginId(user.getId);return new SimpleAuthenticationInfo(info, user.getPassword(), getName());}return null;}

如果像上面这样设置，读取登录信息就是

LoginInfo login = (LoginInfo) SecurityUtils.getSubject().getPrincipal();

如果设置登录信息的地方如下： 

@Overrideprotected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken authenticationToken)throws AuthenticationException {System.out.println("获取登录者信息-->MyShiroRealm.doGetAuthenticationInfo()");UsernamePasswordToken token = (UsernamePasswordToken) authenticationToken;String userS = token.getUsername();User user = userService.findByName(userS);return new SimpleAuthenticationInfo(users, user.getPassword(), getName());}

 读取登录信息就是：

String loginName = (String) SecurityUtils.getSubject().getPrincipal();