详解Spring Boot Oauth2缓存UserDetails到Ehcache

在Spring中有一个类CachingUserDetailsService实现了UserDetailsService接口，该类使用静态代理模式为UserDetailsService提供缓存功能。该类源码如下：

CachingUserDetailsService.java

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;
 }
}

CachingUserDetailsService默认的userCache属性值为new NullUserCache()，该对象并未实现缓存。因为我打算使用EhCache来缓存UserDetails，所以需要使用Spring的EhCacheBasedUserCache类，该类是UserCache接口的实现类，主要是缓存操作。

缓存UserDetails到Ehcache的具体实现如下：

ehcache.xml

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

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

UserDetailsCacheConfig.java

@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;
 }
}

使用

@Autowired
private UserDetailsService userDetailsService;

欢迎关注我的oauthserver项目，仅仅需要运行建表sql，修改数据库的连接配置，即可得到一个Spring Boot Oauth2 Server微服务。项目地址https://github.com/jeesun/oauthserver

来源：http://www.cnblogs.com/rainmer/p/9417108.html