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

@RestController
public class HelloController {

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

@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();
}

public void onLoginSuccess(HttpServletRequest request, HttpServletResponse response, Authentication successfulAuthentication) {
    //拿到用戶名和密碼
    String username = this.retrieveUserName(successfulAuthentication);
    String password = this.retrievePassword(successfulAuthentication);
    //用戶名為空 打印日志
    if (!StringUtils.hasLength(username)) {
        this.logger.debug("Unable to retrieve username");
    } else {
        //密碼為空 通過用戶名再去查詢
        if (!StringUtils.hasLength(password)) {
            UserDetails user = this.getUserDetailsService().loadUserByUsername(username);
            password = user.getPassword();
            //查到的密碼還為空 打印日志 結(jié)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是兩周 也就是說令牌有效期14天
        int tokenLifetime = this.calculateLoginLifetime(request, successfulAuthentication);
        long expiryTime = System.currentTimeMillis();
        expiryTime += 1000L * (long)(tokenLifetime < 0 ? 1209600 : tokenLifetime);
        //生成簽名 signature
        String signatureValue = this.makeTokenSignature(expiryTime, username, password);
        //設(shè)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 通過用戶名、令牌有效期、密碼和key生成rememberMe的令牌 這里的key也就是加密的鹽值
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!");
    }
}

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

public class RememberMeAuthenticationFilter extends GenericFilterBean implements ApplicationEventPublisherAware {
    private void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
      throws IOException, ServletException {
        //獲取當(dāng)前用戶實例 繼續(xù)過濾校驗
   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;
   }
   //登錄獲取Auth
   Authentication rememberMeAuth = this.rememberMeServices.autoLogin(request, response);
   if (rememberMeAuth != null) {
      // Attempt authenticaton via AuthenticationManager
      try {
      //進行remember-me校驗
         rememberMeAuth = this.authenticationManager.authenticate(rememberMeAuth);
         // Store to SecurityContextHolder
         //保存用戶實例
         SecurityContextHolder.getContext().setAuthentication(rememberMeAuth);
         //成功頁面跳轉(zhuǎn)
         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);
         //失敗頁面跳轉(zhuǎn)
         onUnsuccessfulAuthentication(request, response, ex);
      }
   }
   chain.doFilter(request, response);
}
}

@Override
public final Authentication autoLogin(HttpServletRequest request, HttpServletResponse response) {
   //獲取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 {
       //解碼cookie 拿到令牌
      String[] cookieTokens = decodeCookie(rememberMeCookie);
      //通過令牌獲取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;
}