Detailed explanation of SSM integration with Redis in Java

Redis installation and use

The first step is of course to install Redis. Here we take the installation on Windows as an example.

• First download Redis, you can choose msi or zip package installation method

• zip method needs to open the cmd window and run it in the decompressed directory redis-server redis.windows.confStart Redis

• After installation in msi mode, Redis starts by default and does not require any configuration

• You can modify the Redis port number, password and other configurations in the redis.windows.conf file. After the modification is completed, use the redis-server redis.windows.conf command to restart

• Execute in the Redis installation directoryredis-cli -h 127.0.0.1 -p 6379 -a PasswordOpen the Redis operation interface

• If an error (error) ERR operation not permitted is reported, use auth password for verification

SSM integrates Redis

Redis integration is carried out directly based on the framework integration of SSM in the previous article. It should be noted here that the pojo class stored in Redis must implement Serializableinterface .

Configure pom.xml to introduce Redis dependencies

<!--redis--><dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-redis</artifactId>
    <version>1.6.1.RELEASE</version></dependency><dependency>
    <groupId>redis.clients</groupId>
    <artifactId>jedis</artifactId>
    <version>2.7.3</version></dependency>

redis.properties

redis.host=127.0.0.1
redis.port=6379
redis.password=redis
redis.maxIdle=100
redis.maxWait=1000
redis.testOnBorrow=true
redis.timeout=100000
defaultCacheExpireTime=3600

applicationContext-redis.xml

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

    <!--引入Redis配置文件-->
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>classpath:redis.properties</value>
            </list>
        </property>
    </bean>

    <!-- jedis 连接池配置 -->
    <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
        <property name="maxIdle" value="${redis.maxIdle}"/>
        <property name="maxWaitMillis" value="${redis.maxWait}"/>
        <property name="testOnBorrow" value="${redis.testOnBorrow}"/>
    </bean>
    <!-- redis连接工厂 -->
    <bean id="connectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
        <property name="poolConfig" ref="poolConfig"/>
        <property name="port" value="${redis.port}"/>
        <property name="hostName" value="${redis.host}"/>
        <property name="password" value="${redis.password}"/>
        <property name="timeout" value="${redis.timeout}"></property>
    </bean>
    <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
        <property name="connectionFactory" ref="connectionFactory"/>
        <property name="keySerializer">
            <bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
        </property>
        <property name="valueSerializer">
            <bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer"/>
        </property>
    </bean>
    <!-- 缓存拦截器配置 -->
    <bean id="methodCacheInterceptor" class="com.zkh.interceptor.MethodCacheInterceptor">
        <property name="redisUtil" ref="redisUtil"/>
        <property name="defaultCacheExpireTime" value="${defaultCacheExpireTime}"/>
        <!-- 禁用缓存的类名列表 -->
        <property name="targetNamesList">
            <list>
                <value></value>
            </list>
        </property>
        <!-- 禁用缓存的方法名列表 -->
        <property name="methodNamesList">
            <list>
                <value></value>
            </list>
        </property>
    </bean>
    <bean id="redisUtil" class="com.zkh.util.RedisUtil">
        <property name="redisTemplate" ref="redisTemplate"/>
    </bean>
    <!--配置切面拦截方法 -->
    <aop:config proxy-target-class="true">
        <aop:pointcut id="controllerMethodPointcut" expression="
        execution(* com.zkh.service.impl.*.select*(..))"/>
        <aop:advisor advice-ref="methodCacheInterceptor" pointcut-ref="controllerMethodPointcut"/>
    </aop:config></beans>

MethodCacheInterceptor.java

package com.zkh.interceptor;
import com.zkh.util.RedisUtil;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import java.util.List;
/**
* Redis缓存过滤器
*/
public class MethodCacheInterceptor implements MethodInterceptor {
private RedisUtil redisUtil;
private List<String> targetNamesList; // 禁用缓存的类名列表
    private List<String> methodNamesList; // 禁用缓存的方法列表
    private String defaultCacheExpireTime; // 缓存默认的过期时间

    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        Object value = null;

        String targetName = invocation.getThis().getClass().getName();
        String methodName = invocation.getMethod().getName();
        if (!isAddCache(targetName, methodName)) {
        // 跳过缓存返回结果
            return invocation.proceed();
        }
        Object[] arguments = invocation.getArguments();
        String key = getCacheKey(targetName, methodName, arguments);
        try {            // 判断是否有缓存
            if (redisUtil.exists(key)) {
            return redisUtil.get(key);
            }            // 写入缓存
            value = invocation.proceed();
            if (value != null) {
            final String tkey = key;
            final Object tvalue = value;
            new Thread(new Runnable() {
            @Override
                    public void run() {
                        redisUtil.set(tkey, tvalue, Long.parseLong(defaultCacheExpireTime));
                    }
                }).start();
            }
        } catch (Exception e) {
            e.printStackTrace();
            if (value == null) {
            return invocation.proceed();
            }
        }        return value;
    }
    /**
    * 是否加入缓存
    *
    * @return
    */
    private boolean isAddCache(String targetName, String methodName) {
    boolean flag = true;
    if (targetNamesList.contains(targetName)
                || methodNamesList.contains(methodName) || targetName.contains("$$EnhancerBySpringCGLIB$$")) {
            flag = false;
        }        return flag;
    }
    /**

    * 创建缓存key
    *
    * @param targetName

   * @param methodName
   * @param arguments
    */
    private String getCacheKey(String targetName, String methodName,
                               Object[] arguments) {
        StringBuffer sbu = new StringBuffer();
        sbu.append(targetName).append("_").append(methodName);

        if ((arguments != null) && (arguments.length != 0)) {
         for (int i = 0; i < arguments.length; i++) {
                sbu.append("_").append(arguments[i]);
            }
        }        return sbu.toString();
    }    public void setRedisUtil(RedisUtil redisUtil) {
    this.redisUtil = redisUtil;
    }    public void setTargetNamesList(List<String> targetNamesList) {
    this.targetNamesList = targetNamesList;
    }    public void setMethodNamesList(List<String> methodNamesList) {
    this.methodNamesList = methodNamesList;
    }    public void setDefaultCacheExpireTime(String defaultCacheExpireTime) {

    this.defaultCacheExpireTime = defaultCacheExpireTime;
    }
}

RedisUtil.java tool class

package com.zkh.util;import org.apache.log4j.Logger;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.core.ValueOperations;import java.io.Serializable;import java.util.Set;import java.util.concurrent.TimeUnit;/** * Redis工具类 */public class RedisUtil {    private RedisTemplate<Serializable, Object> redisTemplate;    /**     * 批量删除对应的value     *     * @param keys     */
    public void remove(final String... keys) {        for (String key : keys) {            remove(key);
        }
    }    /**     * 批量删除key     *     * @param pattern     */
    public void removePattern(final String pattern) {
        Set<Serializable> keys = redisTemplate.keys(pattern);        if (keys.size() > 0)
            redisTemplate.delete(keys);
    }    /**     * 删除对应的value     *     * @param key     */
    public void remove(final String key) {        if (exists(key)) {
            redisTemplate.delete(key);
        }
    }    /**     * 判断缓存中是否有对应的value     *     * @param key     * @return     */
    public boolean exists(final String key) {        return redisTemplate.hasKey(key);
    }    /**     * 读取缓存     *     * @param key     * @return     */
    public Object get(final String key) {
        Object result = null;
        ValueOperations<Serializable, Object> operations = redisTemplate
                .opsForValue();
        result = operations.get(key);        return result;
    }    /**     * 写入缓存     *     * @param key     * @param value     * @return     */
    public boolean set(final String key, Object value) {        boolean result = false;        try {
            ValueOperations<Serializable, Object> operations = redisTemplate
                    .opsForValue();
            operations.set(key, value);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }        return result;
    }    /**     * 写入缓存     *     * @param key     * @param value     * @return     */
    public boolean set(final String key, Object value, Long expireTime) {        boolean result = false;        try {
            ValueOperations<Serializable, Object> operations = redisTemplate
                    .opsForValue();
            operations.set(key, value);
            redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }        return result;
    }    public void setRedisTemplate(
            RedisTemplate<Serializable, Object> redisTemplate) {        this.redisTemplate = redisTemplate;
    }
}

##Effect display

There are no records in Redis at the beginning. Next, visit the first page of records.

Check the cache again. The records have been stored in Redis, and the first visit will Reading data from Mysql

Press

F5 to refresh the page. You can see from the Tomcat console that there is no progress. SQL query, but reads cached data directly from Redis, reducing the burden on the database

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