快取架構中的服務詳解！SpringBoot中二級快取服務的實現

2021 年 5 月 22 日
筆記
架構

創建快取服務

創建快取服務介面項目

創建myshop-service-redis-api項目,該項目只負責定義介面
創建項目的pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="//maven.apache.org/POM/4.0.0" xmlns:xsi="//www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="//maven.apache.org/POM/4.0.0 //maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.oxford</groupId>
        <artifactId>myshop-dependencies</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../myshop-dependencies/pom.xml</relativePath>
    </parent>

    <artifactId>myshop-service-redis-api</artifactId>
    <packaging>jar</packaging>
</project>

定義數據Redis介面RedisService:

package com.oxford.myshop.service.redis.api

public interface RedisService{
	void set(String key,Object value);
	
	void set(String key,Object value,int seconds);

	void del(String key);

	Object get(String key);
}

創建快取服務提供者項目

創建myshop-service-redis-provider項目,該項目用作快取服務提供者
創建項目的pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="//maven.apache.org/POM/4.0.0" xmlns:xsi="//www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="//maven.apache.org/POM/4.0.0 //maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.oxford</groupId>
        <artifactId>myshop-dependencies</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../myshop-dependencies/pom.xml</relativePath>
    </parent>

    <artifactId>myshop-service-redis-api</artifactId>
    <packaging>jar</packaging>

	<dependencies>
		<!-- Spring Boot Starter Settings-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-redis</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>


		<!--Common Setting-->
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-pool2</artifactId>
		</dependency>
		<dependency>
			<groupId>de.javakaffee</groupId>
			<artifactId>kryo-serializers</artifactId>
		</dependency>

		<!--Project Settings-->
		<dependency>
			<groupId>com.oxford</groupId>
			<artifactId>my-shop-commons-dubbo</artifactId>
			<version>${Project.parent.version}</version>
		</dependency>
		<dependency>
			<groupId>com.oxford</groupId>
			<artifactId>my-shop-service-redis-api</artifactId>
			<version>${Project.parent.version}</version>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<mainClass>com.oxford.myshop.service.redis.provider.MyshopServiceRedisProviderApplication</mainClass>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

Redis底層實現的Java的lettuce客戶端

創建快取服務介面實現類RedisServiceImpl

package com.oxford.myshop.service.redis.provider.api.impl;

@Service(version="${service.versions.redis.v1}")
public class RedisServiceImpl implements RedisService{
	
	@Override
	public void set(String key,Object value){
		redisTemplate.opsForValue().set(key,value);
	}

	@Override
	public void set(String key,Object value,int seconds){
		redisTemplate.opsForValue().set(key,value,seconds,TimeUnit.SECONDS);
	}

	@Override
	public void del(String key){
		redisTemplate.delete(key);
	}

	@Override
	public Object get(String key){
		return redisTemplate.opsForValue().get(key);
	}
}

創建啟動類SpringBootApplication

package com.oxford.myshop.service.redis.provider;

import com.alibaba.dubbo.container.Main;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;



@EnableHystrix
@EnableHystrixDashboard
public class MyShopServiceRedisrProviderApplication {
    public static void main(String[]args) {
        SpringApplication.run(MyShopServiceRedisProviderApplication.class,args);
        Main.main(args);
    }
}

創建配置文件application.yml

spring:
  application:
    name: myshop-service-redis-provider
  redis:
  	lettuce:
      pool:
      	max-active: 8
      	max-idle: 8
      	max-wait: -1ms
      	min-idle: 0
    sentinel:
      master: mymaster
      nodes: 192.168.32.255:26379,192.168.32.255:26380,192.168.32.255:26381
server:
  port: 8503

services:
  version:
    redis:
  	  v1: 1.0.0
    user:
      v1: 1.0.0

dubbo:
  scan:
    basePackages: com.oxford.myshop.service.redis.provider.api.impl
  application:
    id: com.oxford.myshop.service.redis.provider.api
    name: com.oxford.myshop.service.redis.provider.api
    qos-port: 22224
    qos-enable: true
  protocal:
    id: dubbo
    name: dubbo
    port: 20883
    status: server
    serialization: kryo

  regitry:
    id: zookeeper
    address: zookeeper://localhost:2181?backup=192.168.32.255:2182,192.168.32.255:2183

management:
  endpoint:
    dubbo:
      enabled: true
    dubbo-shutdown:
      enabled: true
    dubbo-configs:
      enabled: true
    dubbo-sevicies:
      enabled: true
    dubbo-reference:
      enabled: true
    dubbo-properties:
      enabled: true
  health:
    dubbo:
      status:
        defaults: memory
        extras: load,threadpool

創建快取服務消費者項目

在pom文件中引入redis介面依賴
在快取服務消費者項目的ServiceImpl中調用RedisService

@Reference(version="services.versions.redis.v1")
private RedisService redisService;

MyBatis Redis二級快取

MyBatis快取

一級快取:
- MyBatis會在表示會話的SqlSession對象中建立一個簡單的快取: 將每次查詢到的結果快取起來,當下次查詢的時候,如果判斷先前有個完全一樣的查詢,會直接從快取中直接將結果取出,返回給用戶,不需要再進行一次資料庫查詢
- 一級快取是SqlSession級別的快取:
  - 在操作資料庫時需要構造SqlSession對象
  - 對象中有一個(記憶體區域)數據結構(HashMap)用於存儲快取數據
  - 不同的SqlSession之間的快取數據區域(HashMap)互不影響,
  - 一級快取的作用域是同一個SqlSession
  - 在同一個SqlSession中兩次執行相同的SQL語句: 第一次執行完畢會將資料庫中查詢的數據寫到快取(記憶體),第二次會從快取中獲取數據,將不再從資料庫查詢,從而提高查詢效率
  - 當一個SqlSession結束後該SqlSession中的一級快取就不存在了
  - MyBatis默認開啟一級快取
二級快取:
- 二級快取是Mapper級別的快取: 多個SqlSession去操作同一個Mapper的SQL語句,多個SqlSession去操作資料庫得到數據會存在二級快取區域,多個SqlSession可以共用二級快取,二級快取是跨SqlSession的
- 二級快取的作用域是mapper的同一個namespace
- 不同的SqlSession兩次執行相同namespace下的SQL語句且向SQL中傳遞參數也相同即最終執行相同的SQL語句: 第一次執行完畢會將資料庫中查詢的數據寫到快取(記憶體),第二次會從快取中獲取數據將不再從資料庫查詢,從而提高查詢效率
- MyBatis默認沒有開啟二級快取,需要在setting全局參數中配置開啟二級快取

配置MyBatis二級快取

SpringBoot中開啟MyBatis二級快取

在myshop-service-user-provider的配置文件中開啟MyBatis二級快取

spring:
  application:
    name: myshop-service-user-provider
  datasource:
    druid:
      url: jdbc:mysql://localhost:3306/myshop?useUnicode=true&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
      initial-size: 1
      min-idle: 1
      main-active: 20
      test-on-borrow: true
      driver-class-name: com.mysql.cj.jdbc.Driver
  redis:
  	lettuce:
      pool:
      	max-active: 8
      	max-idle: 8
      	max-wait: -1ms
      	min-idle: 0
    sentinel:
      master: mymaster
      nodes: 192.168.32.255:26379,192.168.32.255:26380,192.168.32.255:26381

server:
  port: 8501

# MyBatis Config properties
mybatis:
  configuration:
  	cache-enabled: true
  type-aliases-package: com.oxford.myshop.commons.domain
  mapper-location: classpath:mapper/*.xml

services:
  version:
  	redis:
  	  v1: 1.0.0
    user:
      v1: 1.0.0

dubbo:
  scan:
    basePackages: com.oxford.myshop.service.user.provider.api.impl
  application:
    id: com.oxford.myshop.service.user.provider.api
    name: com.oxford.myshop.service.user.provider.api
    qos-port: 22222
    qos-enable: true
  protocal:
    id: dubbo
    name: dubbo
    port: 20001
    status: server
    serialization: kryo

  regitry:
    id: zookeeper
    address: zookeeper://localhost:2181?backup=192.168.32.255:2182,192.168.32.255:2183

management:
  endpoint:
    dubbo:
      enabled: true
    dubbo-shutdown:
      enabled: true
    dubbo-configs:
      enabled: true
    dubbo-sevicies:
      enabled: true
    dubbo-reference:
      enabled: true
    dubbo-properties:
      enabled: true
  health:
    dubbo:
      status:
        defaults: memory
        extras: load,threadpool

在myshop-commons-mapper的pom.xml中增加redis依賴:

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-data-redis</artifacted>
</dependency>

<dependency>
	<groupId>org.apache.commons</groupId>
	<artifactId>commons-pool2</artifacted>
</dependency>

實體類實現序列化介面並聲明序列號

private static final long serialVersionUID = 82897704415244673535L

IDEA生成序列號方法:
- 使用GenerateSerialVersionUID插件生成,安裝完插件後在實現了序列化介面的類中
- 使用快捷鍵Alt+Insert即可呼出生成菜單,即可自動生成序列號

實現Mybatis Cache介面,自定義快取為Redis

在myshop-commons項目中創建ApplicationContextHolder類

package com.oxford.myshop.commons.context;

@Component
public class ApplicationContextHolder implements ApplicationContextAware,DisposableBean{

	private static final Logger logger=LoggerFactory.getLogger(ApplicationContext.class);

	private static ApplicationContext applicationContext;

	/**
	 * 獲取存儲在靜態變數中的ApplicationContext
	 */
	 public static ApplicationContext getApplicationContext(){
	 	assertContextInjected();
	 	return applicationContext;
	 }

	/**
	 * 從靜態變數applicationContext中獲取Bean,自動轉型成所賦值對象的類型
	 */
	 public static <T> T getBean(String name){
	 	assertContextInjected();
	 	return (T) applicationContext.getBean(name);
	 }

	/**
	 * 從靜態變數applicationContext中獲取Bean,自動轉型成所賦值對象的類型
	 */
	public static <T> T getBean(Class<T> clazz){
	 	assertContextInjected();
	 	return (T) applicationContext.getBean(clazz);
	 }

	/**
	 * 實現DisposableBean介面,在Context關閉時清理靜態變數
	 */
	 public void destroy() throws Exception{
	 	logger.debug("清除 SpringContext 中的 ApplicationContext: {}",applicationContext);
	 	applicationContext=null;
	 }

	/**
	 * 實現ApplicationContextAware介面,注入Context到靜態變數中
	 */
	 public void setApplicationContext(ApplicationContext applicationContext) throws BeanException{
	 	ApplicationContext.applicationContext=applicationContext;
	 }

	/**
	 * 斷言Context已經注入
	 */
	 private static void assertContextInjected(){
		Validate.validState(applicationContext !=null,"applicationContext 屬性未注入,請在配置文件中配置定義ApplicationContextContext");
	}
}

在myshop-commons-mapper項目中創建一個RedisCache的工具類

package com.oxford.myshop.commons.utils;

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

	private final ReadWriteLock readWriteLock=new ReentranReadWriteLock();
	private final String id;
	private RedisTemplate redisTemplate;

	private static final long EXPIRE_TIME_IN_MINUTES=30		// redis過期時間

	public RedisCache(String id){
		if(id==null){
			throw new IllegalArgumentException("Cache instances require an ID");
		}
		this.id=id;
	}

	@Override
	public String getId(){
		return id;
	}

	/**
	 * Put query result to redis 
	 */
	@Override
	public void putObject(Object key,Object value){
		try{
			RedisTemplate redisTemplate=getRedisTemplate();
			ValueOperations opsForValue=redisTemplate.opsForValue();
			opsForValue.set(key, value, EXPIRE_TIME_IN_MINUTES, TimeUnit.MINUTES);
			logger.debug("Put query result to redis");
		}catch(Throwable t){
			logger.error("Redis put failed",t);
		}
	}

	/**
	 * Get cached query result from redis 
	 */
	 @Override
	 public Object getObject(Object key){
		try{
			RedisTemplate redisTemplate=getRedisTemplate();
			ValueOperations opsForValue=redisTemplate.opsForValue();
			opsForValue.set(key, value, EXPIRE_TIME_IN_MINUTES, TimeUnit.MINUTES);
			logger.debug("Get cache query result from redis");
			return opsForValue.get(key);
		}catch(Throwable t){
			logger.error("Redis get failed, fail over to db");
			return null;
		}
	}

	/**
	 * Get cached query result from redis 
	 */
	 @Override
	 public Object getObject(Object key){
		try{
			RedisTemplate redisTemplate=getRedisTemplate();
			ValueOperations opsForValue=redisTemplate.opsForValue();
			opsForValue.set(key, value, EXPIRE_TIME_IN_MINUTES, TimeUnit.MINUTES);
			logger.debug("Get cache query result from redis");
			return opsForValue.get(key);
		}catch(Throwable t){
			logger.error("Redis get failed, fail over to db");
			return null;
		}
	}

	/**
	 * Remove cached query result from redis 
	 */
	 @Override
	 @SuppressWarnings("unchecked")
	 public Object removeObject(Object key){
		try{
			RedisTemplate redisTemplate=getRedisTemplate();
			redisTemplate.delete(key);
			logger.debug("Remove cached query result from redis");
		}catch(Throwable t){
			logger.error("Redis remove failed");
		}
			return null;
	}

	/**
	 * Clear this cache instance
	 */
	 @Override
	 public void clear(){
	 	RedisTemplate redisTemplate=getRedisTemplate();
	 	redisTemplate.execute((RedisCallback)->{
	 		connection.flushDb();
	 		return null;
	 	});
	 	logger.debug("Clear all the cached query result from redis");
	 }

	@Override
	public int getSize(){
		return 0;
	}
	
	@Override
	public ReadWriteLock getReadWriteLock(){
		return readWriteLock;
	}

	private RedisTemplate getRedisTemplate(){
		if(redisTemplate==null){
			redisTemplate=ApplicationContextHolder.getBean("redisTemplate");
		}
		return redisTemplate;
	}
}

Mapper介面類中標註註解

在Mapper介面類上標註註解,聲明使用二級快取

@CacheNamespace(implementation=RedisCache.class)

Tags: 架構

快取架構中的服務詳解！SpringBoot中二級快取服務的實現

創建快取服務

創建快取服務介面項目

創建快取服務提供者項目

創建快取服務消費者項目

MyBatis Redis二級快取

MyBatis快取

配置MyBatis二級快取

SpringBoot中開啟MyBatis二級快取

實體類實現序列化介面並聲明序列號

實現Mybatis Cache介面,自定義快取為Redis

Mapper介面類中標註註解

VirMach 便宜 VPS

QNews

快取架構中的服務詳解！SpringBoot中二級快取服務的實現

創建快取服務

創建快取服務介面項目

創建快取服務提供者項目

創建快取服務消費者項目

MyBatis Redis二級快取

MyBatis快取

配置MyBatis二級快取

SpringBoot中開啟MyBatis二級快取

實體類實現序列化介面並聲明序列號

實現Mybatis Cache介面,自定義快取為Redis

Mapper介面類中標註註解

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