怎么样通过Redis主从实现读写分离？
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.
*/
@Aspect
public 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://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"> <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig"> <!-- 池中最大链接数 --> <property name="maxTotal" value="100"/> <!-- 池中最大空闲链接数 --> <property name="maxIdle" value="50"/> <!-- 池中最小空闲链接数 --> <property name="minIdle" value="20"/> <!-- 当池中链接耗尽，调用者最大阻塞时间，超出此时间将跑出异常。（单位：毫秒；默认为-1，表示永不超时） --> <property name="maxWaitMillis" value="1000"/> <!-- 参考：http://biasedbit.com/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，并尝试继续获龋（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://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"> <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig"> <!-- 池中最大链接数 --> <property name="maxTotal" value="100"/> <!-- 池中最大空闲链接数 --> <property name="maxIdle" value="50"/> <!-- 池中最小空闲链接数 --> <property name="minIdle" value="20"/> <!-- 当池中链接耗尽，调用者最大阻塞时间，超出此时间将跑出异常。（单位：毫秒；默认为-1，表示永不超时） --> <property name="maxWaitMillis" value="1000"/> <!-- 参考：http://biasedbit.com/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，并尝试继续获龋（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路饭。
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