SSM+redis整合(mybatis整合redis做二级缓存)

SSM：是Spring+Struts+Mybatis ，另外还使用了PageHelper

前言:

　　这里主要是利用redis去做mybatis的二级缓存，mybaits映射文件中所有的select都会刷新已有缓存，如果不存在就会新建缓存，所有的insert，update操作都会更新缓存。(这里需要明白对于注解写的SQL语句不会操作缓存，我的增加方法是注解写的就没有清空缓存，后来改为XML中写就清空缓存了,这个问题没有解决?)

　　redis的好处也显而易见，可以使系统的数据访问性能更高。本节只是展示了整合方法和效果，后面会补齐redis集群、负载均衡和session共享的文章。

开始整合工作:

　　0.目录结构:

UserAction .java

package cn.qlq.Action;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.ServletActionContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;

import com.github.pagehelper.PageHelper;
import com.opensymphony.xwork2.ActionSupport;

import cn.qlq.bean.User;
import cn.qlq.service.UserService;

@Controller
@Scope("prototype")
@SuppressWarnings("all")
public class UserAction extends ActionSupport {
    private Map<String, Object> response;
    @Autowired
    private UserService userService;
    private int id;
    private String name;
    public String add() {
        try {
            userService.addUser(id, name);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "add";
    }

    public String delete() {
        return "delete";
    }

    public String update() {
        return "update";
    }

    public String find() throws Exception {
        User user = userService.findUserById(1);
        System.out.println(user);
        HttpServletRequest request = ServletActionContext.getRequest();
        request.setAttribute("user", user);
        return "find";
    }

    public String findPage() throws Exception {
        response = new HashMap();
        // 第三个参数代表排序方式
        PageHelper.startPage(2, 2, "id desc");
        List<User> users = userService.findUsersByPage();
        response.put("users", users);
        return "success";
    }

    public Map getResponse() {
        return response;
    }

    public void setResponse(Map response) {
        this.response = response;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

　　1.后台启动Redis-server，用redis-cli.exe能连接上则证明开启成功。我是服务注册的Redis。(参考:http://www.cnblogs.com/qlqwjy/p/8554215.html)

　　2.开始整合redis缓存:

首先在pom.xml中增加需要的redis jar包

<!-- jedis依赖 -->
        <dependency>
            <groupId>redis.clients</groupId>
            <artifactId>jedis</artifactId>
            <version>2.7.1</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-redis</artifactId>
            <version>1.6.2.RELEASE</version>
        </dependency>

pom.xml写好后，还需要新增两个配置文件：redis.properties

redis.host=127.0.0.1
redis.port=6379
redis.pass=123456
redis.maxIdle=200
redis.maxActive=1024
redis.maxWait=10000
redis.testOnBorrow=true

其中字段也都很好理解，再加入配置文件：applicationContext-redis.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns="http://www.springframework.org/schema/beans" 
xmlns:context="http://www.springframework.org/schema/context" 
xmlns:aop="http://www.springframework.org/schema/aop" 
xmlns:tx="http://www.springframework.org/schema/tx" 
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd ">

<!-- 连接池基本参数配置，类似数据库连接池 -->
    <context:property-placeholder location="classpath:redis.properties" ignore-unresolvable="true"/>

     <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
         <property name="maxTotal" value="${redis.maxActive}"/>
         <property name="maxIdle" value="${redis.maxIdle}" />
         <property name="testOnBorrow" value="${redis.testOnBorrow}"/>
     </bean>
     
     <!-- 连接池配置，类似数据库连接池 -->
     <bean id="jedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory" >
         <property name="hostName" value="${redis.host}"></property>
         <property name="port" value="${redis.port}"></property>
         <!-- <property name="password" value="${redis.pass}"></property> -->
         <property name="poolConfig"  ref="poolConfig"></property> 
     </bean>
     
      <bean id="redisCacheTransfer" class="cn.qlq.jedis.RedisCacheTransfer">
         <property name="jedisConnectionFactory" ref="jedisConnectionFactory" />
     </bean>
     
</beans>

　　注意，刚开始我的context标签没有加ignore-unresolvable，报了个错误，解决办法参考:http://www.cnblogs.com/qlqwjy/p/8556017.html

配置文件写好后，就开始java代码的编写：

JedisClusterFactory.java

package cn.qlq.jedis;


import java.util.HashSet;
import java.util.Properties;
import java.util.Set;
import java.util.regex.Pattern;

import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.io.Resource;

import redis.clients.jedis.HostAndPort;
import redis.clients.jedis.JedisCluster;

public class JedisClusterFactory implements FactoryBean<JedisCluster>, InitializingBean {

    private Resource addressConfig;
    private String addressKeyPrefix;

    private JedisCluster jedisCluster;
    private Integer timeout;
    private Integer maxRedirections;
    private GenericObjectPoolConfig genericObjectPoolConfig;

    private Pattern p = Pattern.compile("^.+[:]\\d{1,5}\\s*$");

    public JedisCluster getObject() throws Exception {
        return jedisCluster;
    }

    public Class<? extends JedisCluster> getObjectType() {
        return (this.jedisCluster != null ? this.jedisCluster.getClass() : JedisCluster.class);
    }

    public boolean isSingleton() {
        return true;
    }

    private Set<HostAndPort> parseHostAndPort() throws Exception {
        try {
            Properties prop = new Properties();
            prop.load(this.addressConfig.getInputStream());

            Set<HostAndPort> haps = new HashSet<HostAndPort>();
            for (Object key : prop.keySet()) {

                if (!((String) key).startsWith(addressKeyPrefix)) {
                    continue;
                }

                String val = (String) prop.get(key);

                boolean isIpPort = p.matcher(val).matches();

                if (!isIpPort) {
                    throw new IllegalArgumentException("ip 或 port 不合法");
                }
                String[] ipAndPort = val.split(":");

                HostAndPort hap = new HostAndPort(ipAndPort[0], Integer.parseInt(ipAndPort[1]));
                haps.add(hap);
            }

            return haps;
        } catch (IllegalArgumentException ex) {
            throw ex;
        } catch (Exception ex) {
            throw new Exception("解析 jedis 配置文件失败", ex);
        }
    }

    public void afterPropertiesSet() throws Exception {
        Set<HostAndPort> haps = this.parseHostAndPort();

        jedisCluster = new JedisCluster(haps, timeout, maxRedirections, genericObjectPoolConfig);

    }

    public void setAddressConfig(Resource addressConfig) {
        this.addressConfig = addressConfig;
    }

    public void setTimeout(int timeout) {
        this.timeout = timeout;
    }

    public void setMaxRedirections(int maxRedirections) {
        this.maxRedirections = maxRedirections;
    }

    public void setAddressKeyPrefix(String addressKeyPrefix) {
        this.addressKeyPrefix = addressKeyPrefix;
    }

    public void setGenericObjectPoolConfig(GenericObjectPoolConfig genericObjectPoolConfig) {
        this.genericObjectPoolConfig = genericObjectPoolConfig;
    }

}

RedisCache.java

package cn.qlq.jedis;


import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

import org.apache.ibatis.cache.Cache;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.redis.connection.jedis.JedisConnection;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializer;

import redis.clients.jedis.exceptions.JedisConnectionException;

public class RedisCache implements Cache {
    private static final Logger logger = LoggerFactory.getLogger(RedisCache.class);

    private static JedisConnectionFactory jedisConnectionFactory;

    private final String id;

    private final ReadWriteLock rwl = new ReentrantReadWriteLock();
    

    public RedisCache(final String id) {
        if (id == null) {
            throw new IllegalArgumentException("Cache instances require an ID");
        }
        logger.debug("MybatisRedisCache:id=" + id);
        this.id = id;
    }

    /**
     * 清空所有缓存
     */
    public void clear() {
        rwl.readLock().lock();
        JedisConnection connection = null;
        try {
            connection = jedisConnectionFactory.getConnection();
            connection.flushDb();
            connection.flushAll();
            logger.debug("清除缓存.......");
        } catch (JedisConnectionException e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.close();
            }
            rwl.readLock().unlock();
        }
    }

    public String getId() {
        return this.id;
    }

    /**
     * 获取缓存总数量
     */
    public int getSize() {
        int result = 0;
        JedisConnection connection = null;
        try {
            connection = jedisConnectionFactory.getConnection();
            result = Integer.valueOf(connection.dbSize().toString());
            logger.info("添加mybaits二级缓存数量：" + result);
        } catch (JedisConnectionException e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.close();
            }
        }
        return result;
    }

    public void putObject(Object key, Object value) {
        rwl.writeLock().lock();

        JedisConnection connection = null;
        try {
            connection = jedisConnectionFactory.getConnection();
            RedisSerializer<Object> serializer = new JdkSerializationRedisSerializer();
            connection.set(SerializeUtil.serialize(key), SerializeUtil.serialize(value));
            logger.info("添加mybaits二级缓存key=" + key + ",value=" + value);
        } catch (JedisConnectionException e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.close();
            }
            rwl.writeLock().unlock();
        }
    }

    public Object getObject(Object key) {
        // 先从缓存中去取数据,先加上读锁
        rwl.readLock().lock();
        Object result = null;
        JedisConnection connection = null;
        try {
            connection = jedisConnectionFactory.getConnection();
            RedisSerializer<Object> serializer = new JdkSerializationRedisSerializer();
            result = serializer.deserialize(connection.get(serializer.serialize(key)));
            logger.info("命中mybaits二级缓存,value=" + result);

        } catch (JedisConnectionException e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.close();
            }
            rwl.readLock().unlock();
        }
        return result;
    }

    public Object removeObject(Object key) {
        rwl.writeLock().lock();

        JedisConnection connection = null;
        Object result = null;
        try {
            connection = jedisConnectionFactory.getConnection();
            RedisSerializer<Object> serializer = new JdkSerializationRedisSerializer();
            result = connection.expire(serializer.serialize(key), 0);
        } catch (JedisConnectionException e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.close();
            }
            rwl.writeLock().unlock();
        }
        return result;
    }

    public static void setJedisConnectionFactory(JedisConnectionFactory jedisConnectionFactory) {
        RedisCache.jedisConnectionFactory = jedisConnectionFactory;
    }

    public ReadWriteLock getReadWriteLock() {
        // TODO Auto-generated method stub
        return rwl;
    }

}

RedisCacheTransfer.java

package cn.qlq.jedis;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;

/**
 * 静态注入中间类
 */
public class RedisCacheTransfer {
     @Autowired
        public void setJedisConnectionFactory(JedisConnectionFactory jedisConnectionFactory) {
            RedisCache.setJedisConnectionFactory(jedisConnectionFactory);
        }

}

SerializeUtil.java

package cn.qlq.jedis;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

/**
 * 
 * @author qlq
 *
 */
public class SerializeUtil {
    /**
     * 序列化
     */
    public static byte[] serialize(Object object) {
        ObjectOutputStream oos = null;
        ByteArrayOutputStream baos = null;
        try {
            // 序列化
            baos = new ByteArrayOutputStream();
            oos = new ObjectOutputStream(baos);
            oos.writeObject(object);
            byte[] bytes = baos.toByteArray();
            return bytes;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 反序列化
     */
    public static Object unserialize(byte[] bytes) {
        if (bytes != null) {
            ByteArrayInputStream bais = null;
            try {
                // 反序列化
                bais = new ByteArrayInputStream(bytes);
                ObjectInputStream ois = new ObjectInputStream(bais);
                return ois.readObject();
            } catch (Exception e) {

            }
        }
        return null;
    }
}

　　到此，修改就算完成，开始开启二级缓存

3.开启二级缓存:

需要缓存的对象实现序列化接口

Mybatis的全局配置文件开启二级缓存(SqlMapConfig.xml)

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <!-- 开启二级缓存 -->
    <settings>
        <setting name="cacheEnabled" value="true"/>
    </settings>
    
    
    <!--  只需要定义个别名,这个应该有-->
     <typeAliases >
         <package name="cn.qlq.bean"/>
     </typeAliases>       

</configuration>

Mapper.xml中开启二级缓存并设置缓存类(UserMapper.xml)

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!-- namespace命名空间，作用就是对sql进行分类化管理，理解sql隔离 注意：使用mapper代理方法开发，namespace有特殊重要的作用 -->
<mapper namespace="cn.qlq.mapper.UserMapper">
    <!-- 使用Redis二级缓存 -->
    <cache type="cn.qlq.jedis.RedisCache"></cache>

    <select id="findUserById" parameterType="int" resultType="cn.qlq.bean.User">
        select
        * from user where id = #{id}
    </select>

    <select id="findUsersByPage" resultType="cn.qlq.bean.User">
        select * from user
    </select>

    <insert id="addUser">
        insert into user values(#{0},#{1})
    </insert>


</mapper>

4.测试二级缓存:

清空redis的数据

127.0.0.1:6379> flushall
OK
127.0.0.1:6379> keys *
(empty list or set)
127.0.0.1:6379>

启动项目访问并查看日志:

日志如下:(如下底色是黄的是发出的SQL语句，字体是红色的是缓存的命中率为0之后向redis添加缓存)

13:01:05,064 DEBUG DefaultActionInvocation:76 - Executing action method = findPage
13:01:05,091 DEBUG SqlSessionUtils:109 - Creating a new SqlSession
13:01:05,109 DEBUG SqlSessionUtils:145 - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@15546ea6] was not registered for synchronization because synchronization is not active
13:01:05,157 DEBUG LoggingCache:55 - Cache Hit Ratio [SQL_CACHE]: 0.0
13:01:05,350  INFO RedisCache:107 - 命中mybaits二级缓存,value=null
13:01:05,364 DEBUG DataSourceUtils:110 - Fetching JDBC Connection from DataSource
13:01:05,365 DEBUG BasicResourcePool:1644 - trace com.mchange.v2.resourcepool.BasicResourcePool@44083847 [managed: 3, unused: 2, excluded: 0] (e.g. com.mchange.v2.c3p0.impl.NewPooledConnection@29072429)
13:01:05,366 DEBUG SpringManagedTransaction:88 - JDBC Connection [com.mchange.v2.c3p0.impl.NewProxyConnection@75adf2b9] will not be managed by Spring
13:01:05,371 DEBUG findUsersByPage_COUNT:132 - ooo Using Connection [com.mchange.v2.c3p0.impl.NewProxyConnection@75adf2b9]
13:01:05,385 DEBUG findUsersByPage_COUNT:132 - ==>  Preparing: SELECT count(0) FROM user 
13:01:05,447 DEBUG findUsersByPage_COUNT:132 - ==> Parameters: 
13:01:05,487 TRACE findUsersByPage_COUNT:138 - <==    Columns: count(0)
13:01:05,487 TRACE findUsersByPage_COUNT:138 - <==        Row: 7
13:01:05,499  INFO RedisCache:107 - 命中mybaits二级缓存,value=null
13:01:05,500 DEBUG findUsersByPage:132 - ooo Using Connection [com.mchange.v2.c3p0.impl.NewProxyConnection@75adf2b9]
13:01:05,501 DEBUG findUsersByPage:132 - ==>  Preparing: SELECT * FROM user order by id desc LIMIT ?, ? 
13:01:05,502 DEBUG findUsersByPage:132 - ==> Parameters: 2(Integer), 2(Integer)
13:01:05,503 TRACE findUsersByPage:138 - <==    Columns: id, name
13:01:05,504 TRACE findUsersByPage:138 - <==        Row: 4, QLQ4
13:01:05,505 TRACE findUsersByPage:138 - <==        Row: 3, QLQ3
13:01:05,511  INFO RedisCache:87 - 添加mybaits二级缓存key=-167006705:2220054459:cn.qlq.mapper.UserMapper.findUsersByPage_COUNT:0:2147483647:select * from user,value=[7]
13:01:05,515  INFO RedisCache:87 - 添加mybaits二级缓存key=-165358097:5089576455:cn.qlq.mapper.UserMapper.findUsersByPage:0:2147483647:select * from user:2:2:id desc:2,value=[cn.qlq.bean.User@68e9fd61, cn.qlq.bean.User@39835e11]
13:01:05,515 DEBUG SqlSessionUtils:173 - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@15546ea6]
13:01:05,516 DEBUG DataSourceUtils:332 - Returning JDBC Connection to DataSource

打开RedisDesktopManager查看缓存记录

再次访问发现命中缓存，所以没有发出SQL语句:

　　命中率计算方法:第一次访问没有命中为0，所以将缓存加进去。

　　　　　　　　　　第二次命中缓存，命中率为1/2

　　　　　　　　　　第三次命中缓存，命中率为2/3

5.测试清除二级缓存:

　　经过测试发现当SQL语句写在注解上面(mybatis使用注解)的时候不会清除缓存，而写在XML中的语句执行后会清除缓存。

1.注解insert,update,delete不会清除缓存

    // @Insert("insert into user values(#{0},#{1})")
    public int addUser(int id, String name) throws SQLException;

2.Mapper.xml写的SQL语句执行之后会清除缓存

 <insert id="addUser">
        insert into user values(#{0},#{1})
    </insert>

3.测试XML写的SQL执行之后清除缓存

(1)get方式添加一条记录

(2)查看日志:

13:21:37,876 DEBUG addUser:132 - ==>  Preparing: insert into user values(?,?) 
13:21:37,942 DEBUG addUser:132 - ==> Parameters: 8(Integer), QLQ8(String)
13:21:38,087 DEBUG RedisCache:45 - 清除缓存.......

(3)查看redis是否有数据: