在springcloud中我们可以使用 spring-boot-starter-data-redis 已经为我们处理好分布式缓存，但是我们还是不满足于只存在于网络中传输的缓存，我们现在来扩展成本地加Redis 双级缓存，这样就可以减少网络传输带来的传输效率。
以下是针对已经整理好的项目进行直接使用
打包安装项目 springcloud-twocache
git clone https://github.com/dounine/spring-cloud.git
cd spring-cloud
gradle install -xtest
在项目中引用
build.gradle
dependencies {
compile('com.dounine.twocache:springcloud-twocache:0.0.1-SNAPSHOT')
}
在application.yml添加如下代码
spring:
redis:
host: localhost
port: 6379
twocache:
enable: true
redis:
topic: 项目名
java 代码中使用(与 spring cache 使用缓存一样)
@Cacheable(cacheNames = "user",key = "#userId")
public String queryUser(@PathVariable String userId) {
...
}
源码讲解
IpV4.java 节点 IP 获取工具
import java.net.Inet4Address;
import java.net.UnknownHostException;
public final class IpV4 {
private static String node;
static {
try {
node = Inet4Address.getLocalHost().getHostAddress();
} catch (UnknownHostException e) {
e.printStackTrace();
}
}
public static final String get(){
return node;
}
}
NotifyMsg.java Redis 消息通知包装对象
public class NotifyMsg implements Serializable {
private NotifyType notifyType;
private String cacheName;
private String node;
private Object key;
private Object result;
public NotifyMsg(NotifyType notifyType,String node,Object key,Object result){
this.node = node;
this.notifyType = notifyType;
this.key = key;
this.result = result;
}
// get set ...
}
NotifyType.java Redis 缓存通知类型
public enum NotifyType {
PUT,
EVICT,
CLEAR
}
RedisAndLocalCache.java Redis 本地缓存重写
public class RedisAndLocalCache implements Cache {
private ConcurrentHashMap<Object,ValueWrapper> local = new ConcurrentHashMap<>();
private RedisCache redisCache;
private TwoLevelCacheManager cacheManager;
private String node;
public RedisAndLocalCache(TwoLevelCacheManager twoLevelCacheManager,RedisCache redisCache,String node){
this.cacheManager = twoLevelCacheManager;
this.redisCache = redisCache;
this.node = node;
}
@Override
public String getName() {
return redisCache.getName();
}
@Override
public Object getNativeCache() {
return redisCache.getNativeCache();
}
@Override
public ValueWrapper get(Object key) {
ValueWrapper valueWrapper = local.get(key);
if(valueWrapper!=null){
return valueWrapper;
}else{
valueWrapper = redisCache.get(key);
if(valueWrapper!=null){
local.put(key,valueWrapper);
}
return valueWrapper;
}
}
@Override
public <T> T get(Object key, Class<T> type) {
ValueWrapper valueWrapper = local.get(key);
if(valueWrapper!=null){
return (T)valueWrapper.get();
}else{
valueWrapper = redisCache.get(key);
if(valueWrapper!=null){
local.put(key,valueWrapper);
}
return (T)valueWrapper.get();
}
}
@Override
public <T> T get(Object key, Callable<T> valueLoader) {
return null;
}
@Override
public void put(Object key, Object value) {
this.local.put(key,new SimpleValueWrapper(value));
this.redisCache.put(key,value);
this.notifyNodes(new NotifyMsg(NotifyType.PUT,node,key,value));
}
private void notifyNodes(NotifyMsg notifyType){
notifyType.setCacheName(redisCache.getName());
cacheManager.publishMessage(notifyType);
}
@Override
public ValueWrapper putIfAbsent(Object key, Object value) {
return null;
}
@Override
public void evict(Object key) {
redisCache.evict(key);
this.notifyNodes(new NotifyMsg(NotifyType.EVICT,node,key,null));
}
public void clearLocal(){
local.clear();
}
@Override
public void clear() {
redisCache.clear();
this.notifyNodes(new NotifyMsg(NotifyType.CLEAR,node,null,null));
}
}
TwoCacheConfig.java Starter 自动配置类
@Configuration
@ConditionalOnMissingBean(CacheManager.class)
@ConditionalOnBean({RedisTemplate.class})
@ConditionalOnProperty(name = "twocache.enable",havingValue = "true")
@EnableCaching
public class TwoCacheConfig {
@Value("${twocache.redis.topic:towcache}")
private String topic;
@Value("${server.port}")
private Integer port;
@Bean
@ConditionalOnMissingBean(JedisConnectionFactory.class)
JedisConnectionFactory jedisConnectionFactory() {
return new JedisConnectionFactory();
}
@Bean
RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory, MessageListenerAdapter listenerAdapter){
RedisMessageListenerContainer container = new RedisMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.addMessageListener(listenerAdapter,new PatternTopic(topic));
return container;
}
@Bean
MessageListenerAdapter listenerAdapter(final TwoLevelCacheManager cacheManager){
return new MessageListenerAdapter(new MessageListener() {
@Override
public void onMessage(Message message, byte[] pattern) {
try {
String topic = new String(message.getChannel(),"utf-8");
cacheManager.receiver(message.getBody());
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
});
}
@Bean
public TwoLevelCacheManager cacheManager(RedisTemplate redisTemplate){
return new TwoLevelCacheManager(redisTemplate,topic,port);
}
}
TwoLevelCacheManager.java 双级缓存管理器
public class TwoLevelCacheManager extends RedisCacheManager {
private String topic;
private RedisTemplate<String,Object> redisTemplate;
private Integer port;
private String node = IpV4.get();
public TwoLevelCacheManager(RedisTemplate<String,Object> redisTemplate,String topic, Integer port){
super(redisTemplate);
this.redisTemplate = redisTemplate;
this.topic = topic;
this.port = port;
}
@Override
protected Cache decorateCache(Cache cache) {
return new RedisAndLocalCache(this,(RedisCache) cache,node+":"+port);
}
protected void publishMessage(NotifyMsg notifyMsg){
this.redisTemplate.convertAndSend(topic,notifyMsg);
}
public void receiver(byte[] body){
NotifyMsg notifyMsg = (NotifyMsg)this.redisTemplate.getDefaultSerializer().deserialize(body);
RedisAndLocalCache cache = (RedisAndLocalCache) this.getCache(notifyMsg.getCacheName());
if(cache!=null){
if(!notifyMsg.getNode().equals(node+":"+port)){
if(notifyMsg.getNotifyType().equals(NotifyType.CLEAR)){
cache.clearLocal();
}else if(notifyMsg.getNotifyType().equals(NotifyType.PUT)){
cache.put(notifyMsg.getKey(),notifyMsg.getResult());
}else if(notifyMsg.getNotifyType().equals(NotifyType.EVICT)){
cache.evict(notifyMsg.getKey());
}
}else{
// LOGGER.error("消息从自身发送,忽略处理");
}
}
}
}
作者：大猪大猪
链接：https://www.jianshu.com/p/97c0b2ac9caf
来源：简书
简书著作权归作者所有，任何形式的转载都请联系作者获得授权并注明出处。
