在项目开发中使用Redis作缓存

出自https://blog.csdn.net/chenhaotao/article/details/78491558

Redis是nosql非关系型数据库，数据结构以key-value的形式，每个key对应唯一一个value，同时由于Redis数据是运行在内存中的，查询效率非常高，但是又因为是直接占用内存资源的，一般只对高频率的数据进行缓存。

在项目中使用Redis缓存原因： 
1.减轻数据库压力 
2.提高查询效率

 1 Redis的数据结构为key-value，其中value支持五种格数数据：
 2 1.字符串（strings）
 3 2.字符串列表（lists）
 4 3.字符串集合（sets）
 5 4.有序字符串集合（sorted sets）
 6 5.哈希（hashes）
 7 
 8 
 9 
10 在项目中使用Redis缓存流程：
11 1.查询时先从缓存中查询
12 2.缓存中如果没有数据再从数据库查询，并将数据保存进缓存
13 3.如果缓存中查询到数据，直接返回，不再需要查询数据库

数据的缓存同步问题 
如果对数据进行了缓存，当查询数据时，如果缓存中有数据则直接返回缓存数据不会查询数据，当数据库数据改变时就有可能出现数据不一致的问题。可以考虑在每次修改数据库的时候同时将对应的缓存数据删除，这样重新查询的时候就会查询数据库并缓存（针对数据量比较小的情况）。

spring整合Redis

 

xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context-4.0.xsd
    http://code.alibabatech.com/schema/dubbo
    http://code.alibabatech.com/schema/dubbo/dubbo.xsd
    http://www.springframework.org/schema/aop 
    http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
    http://www.springframework.org/schema/mvc
    http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
    http://www.springframework.org/schema/util
    http://www.springframework.org/schema/util/spring-util-4.0.xsd">
    <!-- redis交给spring管理 -->
    <!-- 创建JedisPoolConfig对象 -->
    <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
        <property name="maxTotal" value="1000"></property>
        <property name="maxIdle" value="20"></property>
    </bean>
    <!-- 单机版连接池交给spring管理 -->
    <bean class="redis.clients.jedis.JedisPool">
        <constructor-arg name="poolConfig" ref="poolConfig"></constructor-arg>
        <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
        <constructor-arg name="port" value="6379"></constructor-arg>
    </bean>
    <!-- 集群交给spring管理 -->
    <!-- <bean class="redis.clients.jedis.JedisCluster">
        <constructor-arg name="nodes">
            <set>
                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
                    <constructor-arg name="port" value="7001"></constructor-arg>
                </bean>

                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
                    <constructor-arg name="port" value="7002"></constructor-arg>
                </bean>

                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
                    <constructor-arg name="port" value="7003"></constructor-arg>
                </bean>

                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
                    <constructor-arg name="port" value="7004"></constructor-arg>
                </bean>

                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
                    <constructor-arg name="port" value="7005"></constructor-arg>
                </bean>

                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
                    <constructor-arg name="port" value="7006"></constructor-arg>
                </bean>

                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
                    <constructor-arg name="port" value="7007"></constructor-arg>
                </bean>

                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.66.66"></constructor-arg>
                    <constructor-arg name="port" value="7008"></constructor-arg>
                </bean>

            </set>
        </constructor-arg>
        <constructor-arg name="poolConfig" ref="poolConfig"></constructor-arg>      
    </bean> -->
</beans>

　　jedis接口抽取

 1 public interface JedisDao {
 2 
 3     //抽取jedis访问redis服务器常用方法
 4     //String
 5     public String set(String key,String value);
 6     public String get(String key);
 7     //自增
 8     public Long incr(String key);
 9     //自减
10     public Long decr(String key);
11     //过期时间
12     public Long expire(String key, int seconds);
13     //查询过期剩余时间
14     public Long ttl(String key);
15     //HASH
16     public Long hset(String key, String field, String value);
17     public String hget(String key, String field);
18     //删除
19     public Long hdel(String key, String field);
20 
21 }

单机版Redis接口实现类

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import cn.e3mall.content.dao.JedisDao;
@Repository
public class SingleJedisDaoImpl implements JedisDao {

    //注入单机版jedis连接池对象
    @Autowired
    private JedisPool jp;

    @Override
    public String set(String key, String value) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        String set = jedis.set(key, value);
        return set;
    }

    @Override
    public String get(String key) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        String value = jedis.get(key);
        return value;
    }

    @Override
    public Long incr(String key) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        Long incr = jedis.incr(key);
        return incr;
    }

    @Override
    public Long decr(String key) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        Long decr = jedis.decr(key);
        return decr;
    }

    @Override
    public Long expire(String key, int seconds) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        Long expire = jedis.expire(key, seconds);
        return expire;
    }

    @Override
    public Long ttl(String key) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        Long ttl = jedis.ttl(key);
        return ttl;
    }

    @Override
    public Long hset(String key, String field, String value) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        Long hset = jedis.hset(key, field, value);

        return hset;
    }

    @Override
    public String hget(String key, String field) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        String hget = jedis.hget(key, field);
        return hget;
    }

    @Override
    public Long hdel(String key, String field) {
        // TODO Auto-generated method stub
        Jedis jedis = jp.getResource();
        Long hdel = jedis.hdel(key, field);
        return hdel;
    }

}

集群版Redis接口实现类

 1 import org.springframework.beans.factory.annotation.Autowired;
 2 import org.springframework.stereotype.Repository;
 3 
 4 import redis.clients.jedis.JedisCluster;
 5 import cn.e3mall.content.dao.JedisDao;
 6 @Repository
 7 public class ClusterJedisDaoImpl implements JedisDao {
 8 
 9     //注解集群对象
10     @Autowired
11     private JedisCluster jc;
12 
13     @Override
14     public String set(String key, String value) {
15         // TODO Auto-generated method stub
16         String set = jc.set(key, value);
17         return set;
18     }
19 
20     @Override
21     public String get(String key) {
22         // TODO Auto-generated method stub
23         String string = jc.get(key);
24         return string;
25     }
26 
27     @Override
28     public Long incr(String key) {
29         // TODO Auto-generated method stub
30         Long incr = jc.incr(key);
31         return incr;
32     }
33 
34     @Override
35     public Long decr(String key) {
36         // TODO Auto-generated method stub
37         Long decr = jc.decr(key);
38         return decr;
39     }
40 
41     @Override
42     public Long expire(String key, int seconds) {
43         // TODO Auto-generated method stub
44         Long expire = jc.expire(key, seconds);
45         return expire;
46     }
47 
48     @Override
49     public Long ttl(String key) {
50         // TODO Auto-generated method stub
51         Long ttl = jc.ttl(key);
52         return ttl;
53     }
54 
55     @Override
56     public Long hset(String key, String field, String value) {
57         // TODO Auto-generated method stub
58         Long hset = jc.hset(key, field, value);
59         return hset;
60     }
61 
62     @Override
63     public String hget(String key, String field) {
64         // TODO Auto-generated method stub
65         String value = jc.hget(key, field);
66         return value;
67     }
68 
69     @Override
70     public Long hdel(String key, String field) {
71         // TODO Auto-generated method stub
72         Long hdel = jc.hdel(key, field);
73         return hdel;
74     }
75 
76 }

Redis集群思想 
备份（高可用） 
分块（高效率、高并发）

posted @ 2018-05-30 11:00  有朋远方来  阅读(239)  评论(0)  编辑  收藏  举报