SSO单点登录核心原理

@RequestMapping("/doLogin")
  @ResponseBody
  public SysResult login(User user,HttpServletResponse response) {
    //1.校验数据是否正确.获取密钥
    String ticket = userService.findUserByUP(user);
    if(StringUtils.isEmpty(ticket)) {
      return SysResult.fail();
    }
    //2.如果程序执行到这里.表示密钥有值.写入cookie
    Cookie cookie = new Cookie("JT_TICKET", ticket);
    cookie.setMaxAge(7 * 24 * 3600);
    cookie.setPath("/");
    //设定cookie的共享! 这样当访问order.jt.com或者cart.jt.com的时候都会带上这个Cookie
    cookie.setDomain("jt.com");
    //将cookie写入客户端
    response.addCookie(cookie);
    return SysResult.success();
  }

@Override
  public String findUserByUP(User user) {
    String ticket = null;
    //为了与数据库数据一致,需要将密码加密
    String md5Pass = DigestUtils.md5DigestAsHex(user.getPassword().getBytes());
    user.setPassword(md5Pass);
    QueryWrapper<User> queryWrapper = new QueryWrapper<User>(user);
    //根据用户名和密码校验数据
    User userDB = userMapper.selectOne(queryWrapper);
    if(userDB !=null) {
      //将数据库数据转化为json保存到redis中
      String uuid = UUID.randomUUID().toString();
      ticket = DigestUtils.md5DigestAsHex(uuid.getBytes());
      //进行脱敏处理   100xxx0311  
      userDB.setPassword("123456你信吗??");
      String userJSON = 
          ObjectMapperUtil.toJSON(userDB);
      jedisCluster.setex(ticket,7*24*3600, userJSON);
    }
    return ticket;
  }

@Component //交给spring容器管理
public class UserInterceptor implements HandlerInterceptor{
  private static final String TICKET = "JT_TICKET";
  
  @Autowired
  private JedisCluster jedisCluster;
  /**
   * 实现用户权限认证
   *  1.用户不登陆,不允许访问涉密操作.重定向到
   *  用户登录页面.
   *  2.如果用户登录,则请求予以放行.
   *  
   * 方法说明:
   *  1.boolean  
   *    true: 放行
   *    false: 拦截 配合重定向使用
   * 实现步骤:
   *  1.获取用户的Cookie信息. 获取密钥
   *  2.从redis中获取数据.   
   */
  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
      throws Exception {
    Cookie[] cookies = request.getCookies();
    String ticket = null;
    //判断cookie是有效的.
    if(cookies.length > 0 ) {
      for (Cookie cookie : cookies) {
        if(TICKET.equals(cookie.getName())) {
          ticket = cookie.getValue();
          break;
        }
      }
    }
    
    if(!StringUtils.isEmpty(ticket)) {
      //校验redis中是否有数据
      String userJSON = jedisCluster.get(ticket);
      if(!StringUtils.isEmpty(userJSON)) {
        //实现用户信息的动态获取
        User user = ObjectMapperUtil.toObject(userJSON,User.class);
        request.setAttribute("JT_USER", user);
        UserThreadLocalUtil.set(user);
        return true;
      }
    }
    
    //如果用户没有登录需要重定向到登录页面
    response.sendRedirect("/user/login.html");
    return false; 
  }
  
  
  @Override
  public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
      throws Exception {
    
    //防止内存溢出
    UserThreadLocalUtil.remove();
  }
  
}

public class UserThreadLocalUtil {
  
  private static 
  ThreadLocal<User> userThread = 
          new ThreadLocal<>();
  
  public static void set(User user) {
    
    userThread.set(user);
  }
  
  public static User get() {
    
    return userThread.get();
  }
  
  public static void remove() {
    
    //防止内存泄漏
    userThread.remove();
  }
}

@Configuration
public class MvcConfigurer implements WebMvcConfigurer{
  
  @Autowired
  private UserInterceptor userInterceptor;
  
  /**
   * 拦截器路径:
   *  /cart/*  拦截url请求中/cart/xxxx 下的一级路径
   *  /cart/** 拦截cart下的所有路径
   */
  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    
    registry.addInterceptor(userInterceptor).addPathPatterns("/cart/**","/order/**");
  }
  
}

/**
   * 实现用户登出操作.
   *  0.获取cookie数据
   *  1.删除redis  key~~~ticket
   *  2.删除cookie
   * @return
   */
  @RequestMapping("/logout")
  public String logout(HttpServletRequest request,HttpServletResponse response) {
    Cookie[] cookies = request.getCookies();
    String ticket = null;
    //判断cookie是有效的.
    if(cookies.length > 0 ) {
      for (Cookie cookie : cookies) {
        if(TICKET.equals(cookie.getName())) {
          ticket = cookie.getValue();
          break;
        }
      }
    }
    
    if(!StringUtils.isEmpty(ticket)) {
      //如果数据不为null,则删除数据
      jedisCluster.del(ticket);
      Cookie cookie = new Cookie(TICKET, "");
      cookie.setMaxAge(0); //立即删除
      cookie.setPath("/");
      cookie.setDomain("jt.com");
      response.addCookie(cookie);
    }
    
    //重定向到系统首页
    return "redirect:/"; 
  }