关于Springboot shiro认证授权的详解

import com.zs.springboot.model.User;
import com.zs.springboot.service.UserService;
import com.zs.springboot.util.ResultUtil;
import org.apache.shiro.SecurityUtils;
import org.apache.shiro.authc.*;
import org.apache.shiro.authz.AuthorizationInfo;
import org.apache.shiro.authz.SimpleAuthorizationInfo;
import org.apache.shiro.realm.AuthorizingRealm;
import org.apache.shiro.session.Session;
import org.apache.shiro.subject.PrincipalCollection;
import org.apache.shiro.util.ByteSource;
import org.springframework.beans.factory.annotation.Autowired;

import java.util.List;
import java.util.Map;

/**
 * @author zs
 * 登录realm
 */
public class LoginRealm extends AuthorizingRealm {

  @Autowired
  private UserService userService;
  /**
   * 授权方法，只有页面出现关于权限标签的时候或者项目中关于授权注解的时候，才可以被使用
   * @param principal
   * @return
   */
  @Override
  protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principal) {　
    User user = (User) principal.getPrimaryPrincipal();
    Map<String, Object> resultMap1 = userService.getRoleByUid(user.getUid());
    //获取角色，通过多表查询获取用户对应的角色
    List<String> roleList = (List<String>) ResultUtil.getResult(resultMap1);
    SimpleAuthorizationInfo info = new SimpleAuthorizationInfo();
    info.addRoles(roleList);
    //获取权限，通过关联中间表，多表查询出该用户对应的角色所拥有的权限
    Map<String, Object> resultMap2 = userService.getPromessionByUid(user.getUid());
    List<String> permissionList = (List<String>) ResultUtil.getResult(resultMap2);
    info.addStringPermissions(permissionList);
    return info;
  }

  /**
   * 认证方法
   * @param token
   * @return
   * @throws AuthenticationException
   */
  @Override
  protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {
    //获取当前登录的用户名
    String username = (String) token.getPrincipal();
    //根据用户到数据库搜索用户信息
    Map<String, Object> login = userService.login(username);
    //如果用户不存在则抛出异常
    if ((Integer) login.get("code") == 404) {
      throw new UnknownAccountException("用户不存在");
    }
    //如果用户存在，获取用户信息
    User user = (User) login.get("result");
    //进行认证
    SimpleAuthenticationInfo info = new SimpleAuthenticationInfo(user, user.getPassword(), ByteSource.Util.bytes(user.getSalt()), this.getName());
    //将用户信息放入session中，密码制空
    Session session = SecurityUtils.getSubject().getSession();
    user.setPassword(null);
    session.setAttribute("user", user);
    return info;
  }
}