public class CachingUserDetailsService implements UserDetailsService {
  private UserCache userCache = new NullUserCache();
  private final UserDetailsService delegate;

  CachingUserDetailsService(UserDetailsService delegate) {
    this.delegate = delegate;
  }

  public UserCache getUserCache() {
    return this.userCache;
  }

  public void setUserCache(UserCache userCache) {
    this.userCache = userCache;
  }

  public UserDetails loadUserByUsername(String username) {
    UserDetails user = this.userCache.getUserFromCache(username);
    if (user == null) {
      user = this.delegate.loadUserByUsername(username);
    }

    Assert.notNull(user, "UserDetailsService " + this.delegate + " returned null for username " + username + ". This is an interface contract violation");
    this.userCache.putUserInCache(user);
    return user;
  }
}

<?xml version="1.0" encoding="UTF-8"?>
<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="http://ehcache.org/ehcache.xsd">
  <!-- 磁盤緩存位置 -->
  <diskStore path="java.io.tmpdir" />

  <cache name="userCache"
      maxElementsInMemory="0"
      eternal="true"
      overflowToDisk="true"
      diskPersistent="true"
      memoryStoreEvictionPolicy="LRU">
  </cache>
</ehcache>

@Slf4j
@Configuration
public class UserDetailsCacheConfig {
  @Autowired
  private CustomUserDetailsService customUserDetailsService;

  @Bean
  public UserCache userCache(){
    try {
      EhCacheBasedUserCache userCache = new EhCacheBasedUserCache();
      val cacheManager = CacheManager.getInstance();
      val cache = cacheManager.getCache("userCache");
      userCache.setCache(cache);
      return userCache;
    } catch (Exception e) {
      e.printStackTrace();
      log.error(e.getMessage());
    }
    return null;
  }

  @Bean
  public UserDetailsService userDetailsService(){
    Constructor<CachingUserDetailsService> ctor = null;
    try {
      ctor = CachingUserDetailsService.class.getDeclaredConstructor(UserDetailsService.class);
    } catch (NoSuchMethodException e) {
      e.printStackTrace();
    }
    Assert.notNull(ctor, "CachingUserDetailsService constructor is null");
    ctor.setAccessible(true);

    CachingUserDetailsService cachingUserDetailsService = BeanUtils.instantiateClass(ctor, customUserDetailsService);
    cachingUserDetailsService.setUserCache(userCache());
    return cachingUserDetailsService;
  }
}

@Autowired
private UserDetailsService userDetailsService;