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1.快速了解缓存穿透与缓存雪崩
2.springBoot注解大全
3.springBoot之Thymeleaf
一、在pom文件中添加依赖
<!-- https://mvnrepository.com/artifact/redis.clients/jedis -->
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>3.0.1</version>
</dependency>
二、准备JedisClient接口
public interface JedisClient {
String set(String key, String value);
String get(String key);
Boolean exists(String key);
Long expire(String key, int seconds);
Long ttl(String key);
Long incr(String key);
Long hset(String key, String field, String value);
String hget(String key, String field);
Long hdel(String key, String... field);
}
三、实现
1.单机版
public class JedisClientPool implements JedisClient {
@Autowired
private JedisPool jedisPool;
@Override
public String set(String key, String value) {
Jedis jedis = jedisPool.getResource();
String result = jedis.set(key, value);
jedis.close();
return result;
}
@Override
public String get(String key) {
Jedis jedis = jedisPool.getResource();
String result = jedis.get(key);
jedis.close();
return result;
}
@Override
public Boolean exists(String key) {
Jedis jedis = jedisPool.getResource();
Boolean result = jedis.exists(key);
jedis.close();
return result;
}
@Override
public Long expire(String key, int seconds) {
Jedis jedis = jedisPool.getResource();
Long result = jedis.expire(key, seconds);
jedis.close();
return result;
}
@Override
public Long ttl(String key) {
Jedis jedis = jedisPool.getResource();
Long result = jedis.ttl(key);
jedis.close();
return result;
}
@Override
public Long incr(String key) {
Jedis jedis = jedisPool.getResource();
Long result = jedis.incr(key);
jedis.close();
return result;
}
@Override
public Long hset(String key, String field, String value) {
Jedis jedis = jedisPool.getResource();
Long result = jedis.hset(key, field, value);
jedis.close();
return result;
}
@Override
public String hget(String key, String field) {
Jedis jedis = jedisPool.getResource();
String result = jedis.hget(key, field);
jedis.close();
return result;
}
@Override
public Long hdel(String key, String... field) {
Jedis jedis = jedisPool.getResource();
Long result = jedis.hdel(key, field);
jedis.close();
return result;
}
}
(2)集群版
public class JedisClientCluster implements JedisClient {
@Autowired
private JedisCluster jedisCluster;
@Override
public String set(String key, String value) {
return jedisCluster.set(key, value);
}
@Override
public String get(String key) {
return jedisCluster.get(key);
}
@Override
public Boolean exists(String key) {
return jedisCluster.exists(key);
}
@Override
public Long expire(String key, int seconds) {
return jedisCluster.expire(key, seconds);
}
@Override
public Long ttl(String key) {
return jedisCluster.ttl(key);
}
@Override
public Long incr(String key) {
return jedisCluster.incr(key);
}
@Override
public Long hset(String key, String field, String value) {
return jedisCluster.hset(key, field, value);
}
@Override
public String hget(String key, String field) {
return jedisCluster.hget(key, field);
}
@Override
public Long hdel(String key, String... field) {
return jedisCluster.hdel(key, field);
}
四、配置文件
<!-- redis单机版 -->
<bean id="jedisPool" class="redis.clients.jedis.JedisPool">
<constructor-arg name="host" value="192.168.206.132"/>
<constructor-arg name="port" value="7001"/>
</bean>
<bean id="jedisClientPool" class="com.taotao.jedis.JedisClientPool"/>
注意:使用集群版则注释掉单机版,反之一样
这里将集群配置在同一台机器上,开了6个不同的端口,也叫作伪分布式,你也可以开6台机器,然后修改ip和端口。
为什么要6台机器?
什么是集群?集群中至少应该有三个节点。要保证集群的高可用,需要每个节点有一个备份机。(如果需要具体的搭建步骤,可以去看我的博客,里面每一步都有截图
)
<!-- redis集群 -->
<bean id="jedisCluster" class="redis.clients.jedis.JedisCluster">
<constructor-arg>
<set>
<bean class="redis.clients.jedis.HostAndPort">
<constructor-arg name="host" value="192.168.206.132"/>
<constructor-arg name="port" value="7001"/>
</bean>
<bean class="redis.clients.jedis.HostAndPort">
<constructor-arg name="host" value="192.168.25.132"/>
<constructor-arg name="port" value="7002"/>
</bean>
<bean class="redis.clients.jedis.HostAndPort">
<constructor-arg name="host" value="192.168.25.132"/>
<constructor-arg name="port" value="7003"/>
</bean>
<bean class="redis.clients.jedis.HostAndPort">
<constructor-arg name="host" value="192.168.206.132"/>
<constructor-arg name="port" value="7004"/>
</bean>
<bean class="redis.clients.jedis.HostAndPort">
<constructor-arg name="host" value="192.168.206.132"/>
<constructor-arg name="port" value="7005"/>
</bean>
<bean class="redis.clients.jedis.HostAndPort">
<constructor-arg name="host" value="192.168.206.132"/>
<constructor-arg name="port" value="7006"/>
</bean>
</set>
</constructor-arg>
</bean>
<bean id="jedisClientCluster" class="com.taotao.jedis.JedisClientCluster"/>
五、测试
@Test
public void testJedis(){
//初始化spring容器
ApplicationContext applicationContext=new ClassPathXmlApplicationContext("classpath:spring/applicationContext-redis.xml");
//从容器中获得jedisclient对象
JedisClient jedisClient = applicationContext.getBean(JedisClient.class);
//使用JedisClient操作redis
jedisClient.set("ok", "test666");
String result = jedisClient.get("ok");
System.out.println(result);
}
六、向业务逻辑中添加缓存
添加缓存不能影响正常的业务逻辑
查询时,业务中应该先去缓存中查询
如果缓存中没有,在数据库查询
将数据库查询到的结果添加到缓存中
推荐使用的数据类型为hash
举例:
public List<TbContent> getContentList(long cid) {
//查询缓存
try {
String json = jedisClient.hget(CONTENT_KEY, cid + "");
//判断json是否为空
if (StringUtils.isNotBlank(json)) {
//把json转换成list
List<TbContent> list = JsonUtils.jsonToList(json, TbContent.class);
return list;
}
} catch (Exception e) {
e.printStackTrace();
}
//根据cid查询内容列表
TbContentExample example = new TbContentExample();
//设置查询条件
Criteria criteria = example.createCriteria();
criteria.andCategoryIdEqualTo(cid);
//执行查询
List<TbContent> list = contentMapper.selectByExample(example);
//向缓存中添加数据
try {
jedisClient.hset(CONTENT_KEY, cid + "", JsonUtils.objectToJson(list));
} catch (Exception e) {
e.printStackTrace();
}
return list;
}
七、缓存同步
对内容信息做增删改操作后只需要把对应缓存删除即可
//缓存同步
jedisClient.hdel(CONTENT_KEY, content.getCategoryId().toString());
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