Spring Security实现自动登陆功能示例

当我们在登录像QQ邮箱这种大多数的网站，往往在登录按键上会有下次自动登录这个选项，勾选后登录成功，在一段时间内，即便退出浏览器或者服务器重启，再次访问不需要用户输入账号密码进行登录，这也解决了用户每次输入账号密码的麻烦。

接下来实现自动登陆。

applicatio.properties配置用户名密码

spring.security.user.name=java
spring.security.user.password=java

controller层实现

@RestController
public class HelloController {

@GetMapping("/hello")
   public String hello() {
       return "hello";
   }
}

配置类实现

@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {
   @Override
   protected void configure(HttpSecurity http) throws Exception {
   http.formLogin()
           .and()
           .authorizeRequests()
           .anyRequest()
           .authenticated()
           .and()
           .rememberMe()
           .and()
           .csrf().disable();
}

访问http://localhost:8080/hello，此时系统会重定向到登录页面。

二话不说，输入账号密码，开搞！

此时看到了登录数据remember-me的值为on，当自定义登陆框的时候应该知道如何定义key了吧。

在hello接口，可以很清楚的看到cookie里保存了一个remember-me的令牌，这个就是自动登录的关键所在。

至于令牌是怎么生成的，先看一段源码。核心处理类TokenBasedRememberMeServices->onLoginSuccess

public void onLoginSuccess(HttpServletRequest request, HttpServletResponse response, Authentication successfulAuthentication) {
   //拿到用户名和密码
   String username = this.retrieveUserName(successfulAuthentication);
   String password = this.retrievePassword(successfulAuthentication);
   //用户名为空 打印日志
   if (!StringUtils.hasLength(username)) {
       this.logger.debug("Unable to retrieve username");
   } else {
       //密码为空 通过用户名再去查询
       if (!StringUtils.hasLength(password)) {
           UserDetails user = this.getUserDetailsService().loadUserByUsername(username);
           password = user.getPassword();
           //查到的密码还为空 打印日志 结束
           if (!StringUtils.hasLength(password)) {
               this.logger.debug("Unable to obtain password for user: " + username);
               return;
           }
       }
       //令牌有效期的生成 1209600是两周 也就是说令牌有效期14天
       int tokenLifetime = this.calculateLoginLifetime(request, successfulAuthentication);
       long expiryTime = System.currentTimeMillis();
       expiryTime += 1000L * (long)(tokenLifetime < 0 ? 1209600 : tokenLifetime);
       //生成签名 signature
       String signatureValue = this.makeTokenSignature(expiryTime, username, password);
       //设置cookie
       this.setCookie(new String[]{username, Long.toString(expiryTime), signatureValue}, tokenLifetime, request, response);
       if (this.logger.isDebugEnabled()) {
           this.logger.debug("Added remember-me cookie for user '" + username + "', expiry: '" + new Date(expiryTime) + "'");
       }
   }
}

//使用MD5加密 通过用户名、令牌有效期、密码和key生成rememberMe的令牌 这里的key也就是加密的盐值
protected String makeTokenSignature(long tokenExpiryTime, String username, String password) {
   String data = username + ":" + tokenExpiryTime + ":" + password + ":" + this.getKey();

try {
       MessageDigest digest = MessageDigest.getInstance("MD5");
       return new String(Hex.encode(digest.digest(data.getBytes())));
   } catch (NoSuchAlgorithmException var7) {
       throw new IllegalStateException("No MD5 algorithm available!");
   }
}

看完了核心的源码，也就知道了令牌的生成规则：username + “:” + tokenExpiryTime + “:” + password + “:” + key（key 是一个散列盐值，可以用来防治令牌被修改，通过MD5散列函数生成。），然后通过Base64编码。

取出刚才的remember-me=amF2YToxNjM3MTI2MDk1OTMxOmQ5OGI3OTY5OTE4ZmQwMzE3ZWUyY2U4Y2MzMjQxZGQ0进行下验证。

解码后是java:1637126095931:d98b7969918fd0317ee2ce8cc3241dd4，很明显java是username，1637126095931是两周后的tokenExpiryTime，d98b7969918fd0317ee2ce8cc3241dd4是password和key值的MD5加密生成的。

需要注意的是key值是通过UUID随机生成的，当重启服务器时，UUID的变化会导致自动登录失败，所以为了避免之前生成的令牌失效，可以在配置中定义key值。

@Override
protected void configure(HttpSecurity http) throws Exception {
   http.formLogin()
           .and()
           .authorizeRequests()
           .anyRequest()
           .authenticated()
           .and()
           .rememberMe()
           .key("HelloWorld")
           .and()
           .csrf().disable();
}

在Spring Security—登陆流程分析曾经说到 Spring Security中的认证授权都是通过过滤器来实现的。RememberMeAuthenticationFilter 是自动登录的核心过滤器。

public class RememberMeAuthenticationFilter extends GenericFilterBean implements ApplicationEventPublisherAware {
   private void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
     throws IOException, ServletException {
       //获取当前用户实例 继续过滤校验
  if (SecurityContextHolder.getContext().getAuthentication() != null) {
     this.logger.debug(LogMessage
           .of(() -> "SecurityContextHolder not populated with remember-me token, as it already contained: '"
                 + SecurityContextHolder.getContext().getAuthentication() + "'"));
     chain.doFilter(request, response);
     return;
  }
  //登录获取Auth
  Authentication rememberMeAuth = this.rememberMeServices.autoLogin(request, response);
  if (rememberMeAuth != null) {
     // Attempt authenticaton via AuthenticationManager
     try {
     //进行remember-me校验
        rememberMeAuth = this.authenticationManager.authenticate(rememberMeAuth);
        // Store to SecurityContextHolder
        //保存用户实例
        SecurityContextHolder.getContext().setAuthentication(rememberMeAuth);
        //成功页面跳转
        onSuccessfulAuthentication(request, response, rememberMeAuth);
        this.logger.debug(LogMessage.of(() -> "SecurityContextHolder populated with remember-me token: '"
              + SecurityContextHolder.getContext().getAuthentication() + "'"));
        if (this.eventPublisher != null) {
           this.eventPublisher.publishEvent(new InteractiveAuthenticationSuccessEvent(
                 SecurityContextHolder.getContext().getAuthentication(), this.getClass()));
        }
        if (this.successHandler != null) {
           this.successHandler.onAuthenticationSuccess(request, response, rememberMeAuth);
           return;
        }
     }
     catch (AuthenticationException ex) {
        this.logger.debug(LogMessage
              .format("SecurityContextHolder not populated with remember-me token, as AuthenticationManager "
                    + "rejected Authentication returned by RememberMeServices: '％s'; "
                    + "invalidating remember-me token", rememberMeAuth),
              ex);
        this.rememberMeServices.loginFail(request, response);
        //失败页面跳转
        onUnsuccessfulAuthentication(request, response, ex);
     }
  }
  chain.doFilter(request, response);
}
}

@Override
public final Authentication autoLogin(HttpServletRequest request, HttpServletResponse response) {
  //获取cookie
  String rememberMeCookie = extractRememberMeCookie(request);
  if (rememberMeCookie == null) {
     return null;
  }
  this.logger.debug("Remember-me cookie detected");
  if (rememberMeCookie.length() == 0) {
     this.logger.debug("Cookie was empty");
     cancelCookie(request, response);
     return null;
  }
  try {
      //解码cookie 拿到令牌
     String[] cookieTokens = decodeCookie(rememberMeCookie);
     //通过令牌获取UserdDetails
     UserDetails user = processAutoLoginCookie(cookieTokens, request, response);
     this.userDetailsChecker.check(user);
     this.logger.debug("Remember-me cookie accepted");
     return createSuccessfulAuthentication(request, user);
  }
  catch (CookieTheftException ex) {
     cancelCookie(request, response);
     throw ex;
  }
  catch (UsernameNotFoundException ex) {
     this.logger.debug("Remember-me login was valid but corresponding user not found.", ex);
  }
  catch (InvalidCookieException ex) {
     this.logger.debug("Invalid remember-me cookie: " + ex.getMessage());
  }
  catch (AccountStatusException ex) {
     this.logger.debug("Invalid UserDetails: " + ex.getMessage());
  }
  catch (RememberMeAuthenticationException ex) {
     this.logger.debug(ex.getMessage());
  }
  cancelCookie(request, response);
  return null;
}

大致整体流程就是如果拿不到实例，则进行remember-me验证，通过autoLogin方法里获取cookie，解析令牌，拿到Auth，最后进行校验。之后剩下的和登陆流程分析的差不多。

来源：https://blog.csdn.net/MAKEJAVAMAN/article/details/121128043