前言

大家在工作中可能会遇到这样的需求，即Redis读写分离，目的是为了压力分散化。下面我将为大家介绍借助AWS的ELB实现读写分离，以写主读从为例。

实现

引用库文件

<!-- redis客户端 --> <dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>2.6.2</version> </dependency>

方式一，借助切面

JedisPoolSelector

此类的目的是为读和写分别配置不同的注解，用来区分是主还是从。

package com.silence.spring.redis.readwriteseparation;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * Created by keysilence on 16/10/26. */@Retention(RetentionPolicy.RUNTIME)@Target(ElementType.METHOD)public @interface JedisPoolSelector { String value();}

JedisPoolAspect

此类的目的是针对主和从的注解，进行动态链接池调配，即主的使用主链接池，从的使用从连接池。

package com.silence.spring.redis.readwriteseparation;import org.aspectj.lang.JoinPoint;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.annotation.Before;import org.aspectj.lang.annotation.Pointcut;import org.aspectj.lang.reflect.MethodSignature;import org.springframework.beans.BeansException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import redis.clients.jedis.JedisPool;import javax.annotation.PostConstruct;import java.lang.reflect.Method;import java.util.Date;/** * Created by keysilence on 16/10/26. */@Aspectpublic class JedisPoolAspect implements ApplicationContextAware { private ApplicationContext ctx; @PostConstruct public void init() { System.out.println("jedis pool aspectj started @" + new Date()); } @Pointcut("execution(* com.silence.spring.redis.readwriteseparation.util.*.*(..))") private void allMethod() { } @Before("allMethod()") public void before(JoinPoint point) { Object target = point.getTarget(); String method = point.getSignature().getName(); Class classz = target.getClass(); Class<?>[] parameterTypes = ((MethodSignature) point.getSignature()) .getMethod().getParameterTypes(); try { Method m = classz.getMethod(method, parameterTypes); if (m != null && m.isAnnotationPresent(JedisPoolSelector.class)) { JedisPoolSelector data = m .getAnnotation(JedisPoolSelector.class); JedisPool jedisPool = (JedisPool) ctx.getBean(data.value()); DynamicJedisPoolHolder.putJedisPool(jedisPool); } } catch (Exception e) { e.printStackTrace(); } } public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { this.ctx = applicationContext; }}

DynamicJedisPoolHolder

此类目的是存储当前使用的JedisPool，即上面类赋值后的结果保存。

package com.silence.spring.redis.readwriteseparation;import redis.clients.jedis.JedisPool;/** * Created by keysilence on 16/10/26. */public class DynamicJedisPoolHolder { public static final ThreadLocal<JedisPool> holder = new ThreadLocal<JedisPool>(); public static void putJedisPool(JedisPool jedisPool) { holder.set(jedisPool); } public static JedisPool getJedisPool() { return holder.get(); }}

RedisUtils

此类目的是对Redis具体的调用，里面包含使用主还是从的方式调用。

package com.silence.spring.redis.readwriteseparation.util;import com.silence.spring.redis.readwriteseparation.DynamicJedisPoolHolder;import com.silence.spring.redis.readwriteseparation.JedisPoolSelector;import org.slf4j.Logger;import org.slf4j.LoggerFactory;/** * Created by keysilence on 16/10/26. */public class RedisUtils { private static Logger logger = LoggerFactory.getLogger(RedisUtils.class); @JedisPoolSelector("master") public String setString(final String key, final String value) { String ret = DynamicJedisPoolHolder.getJedisPool().getResource().set(key, value); System.out.println("key:" + key + ",value:" + value + ",ret:" + ret); return ret; } @JedisPoolSelector("slave") public String get(final String key) { String ret = DynamicJedisPoolHolder.getJedisPool().getResource().get(key); System.out.println("key:" + key + ",ret:" + ret); return ret; }}

spring-datasource.xml

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http:///redis-jedispool-configuration/ --> <!-- 调用者获取链接时，是否检测当前链接有效性。无效则从链接池中移除，并尝试继续获取。（默认为false） --> <property name="testOnBorrow" value="true" /> <!-- 向链接池中归还链接时，是否检测链接有效性。（默认为false） --> <property name="testOnReturn" value="true" /> <!-- 调用者获取链接时，是否检测空闲超时。如果超时，则会被移除（默认为false） --> <property name="testWhileIdle" value="true" /> <!-- 空闲链接检测线程一次运行检测多少条链接 --> <property name="numTestsPerEvictionRun" value="10" /> <!-- 空闲链接检测线程检测周期。如果为负值，表示不运行检测线程。（单位：毫秒，默认为-1） --> <property name="timeBetweenEvictionRunsMillis" value="60000" /> <!-- 链接获取方式。队列：false；栈：true --> <!--<property name="lifo" value="false" />--> </bean> <bean id="master" class="redis.clients.jedis.JedisPool"> <constructor-arg index="0" ref="poolConfig"/> <constructor-arg index="1" value="192.168.100.110" type="java.lang.String"/> <constructor-arg index="2" value="6379" type="int"/> </bean> <bean id="slave" class="redis.clients.jedis.JedisPool"> <constructor-arg index="0" ref="poolConfig"/> <!-- 此处Host配置成ELB地址 --> <constructor-arg index="1" value="192.168.100.110" type="java.lang.String"/> <constructor-arg index="2" value="6380" type="int"/> </bean> <bean id="redisUtils" class="com.silence.spring.redis.readwriteseparation.util.RedisUtils"> </bean> <bean id="jedisPoolAspect" class="com.silence.spring.redis.readwriteseparation.JedisPoolAspect" /> <aop:aspectj-autoproxy proxy-target-class="true"/></beans>

Test

package com.silence.spring.redis.readwriteseparation;import com.silence.spring.redis.readwriteseparation.util.RedisUtils;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;/** * Created by keysilence on 16/10/26. */public class Test { public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext("spring-datasource.xml"); System.out.println(ctx); RedisUtils redisUtils = (RedisUtils) ctx.getBean("redisUtils"); redisUtils.setString("aaa", "111"); System.out.println(redisUtils.get("aaa")); }}

方式二，依赖注入

与方式一类似，但是需要写死具体使用主的池还是从的池，思路如下：
放弃注解的方式，直接将主和从的两个链接池注入到具体实现类中。

RedisUtils

package com.silence.spring.redis.readwriteseparation.util;import com.silence.spring.redis.readwriteseparation.DynamicJedisPoolHolder;import com.silence.spring.redis.readwriteseparation.JedisPoolSelector;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import redis.clients.jedis.JedisPool;/** * Created by keysilence on 16/10/26. */public class RedisUtils { private static Logger logger = LoggerFactory.getLogger(RedisUtils.class); private JedisPool masterJedisPool; private JedisPool slaveJedisPool; public void setMasterJedisPool(JedisPool masterJedisPool) { this.masterJedisPool = masterJedisPool; } public void setSlaveJedisPool(JedisPool slaveJedisPool) { this.slaveJedisPool = slaveJedisPool; } public String setString(final String key, final String value) { String ret = masterJedisPool.getResource().set(key, value); System.out.println("key:" + key + ",value:" + value + ",ret:" + ret); return ret; } public String get(final String key) { String ret = slaveJedisPool.getResource().get(key); System.out.println("key:" + key + ",ret:" + ret); return ret; }}

spring-datasource.xml

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http:///redis-jedispool-configuration/ --> <!-- 调用者获取链接时，是否检测当前链接有效性。无效则从链接池中移除，并尝试继续获取。（默认为false） --> <property name="testOnBorrow" value="true" /> <!-- 向链接池中归还链接时，是否检测链接有效性。（默认为false） --> <property name="testOnReturn" value="true" /> <!-- 调用者获取链接时，是否检测空闲超时。如果超时，则会被移除（默认为false） --> <property name="testWhileIdle" value="true" /> <!-- 空闲链接检测线程一次运行检测多少条链接 --> <property name="numTestsPerEvictionRun" value="10" /> <!-- 空闲链接检测线程检测周期。如果为负值，表示不运行检测线程。（单位：毫秒，默认为-1） --> <property name="timeBetweenEvictionRunsMillis" value="60000" /> <!-- 链接获取方式。队列：false；栈：true --> <!--<property name="lifo" value="false" />--> </bean> <bean id="masterJedisPool" class="redis.clients.jedis.JedisPool"> <constructor-arg index="0" ref="poolConfig"/> <constructor-arg index="1" value="192.168.100.110" type="java.lang.String"/> <constructor-arg index="2" value="6379" type="int"/> </bean> <bean id="slaveJedisPool" class="redis.clients.jedis.JedisPool"> <constructor-arg index="0" ref="poolConfig"/> <constructor-arg index="1" value="192.168.100.110" type="java.lang.String"/> <constructor-arg index="2" value="6380" type="int"/> </bean> <bean id="redisUtils" class="com.silence.spring.redis.readwriteseparation.util.RedisUtils"> <property name="masterJedisPool" ref="masterJedisPool"/> <property name="slaveJedisPool" ref="slaveJedisPool"/> </bean></beans>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。