20、springcloud如何使用spring-cache

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BUG弄潮儿 2020-05-01 08:25:12 博主文章分类：spring ©著作权

文章标签 springboot springcloud 文章分类 Java 后端开发

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学了springcloud如何操作数据库进行增删改查，又学了springcloud如何操作reids把数据存储到redis。今天结合数据库操作和reids操作，来看看如何使用SpringCache。SpringCache提供了基于注解的缓存配置方法。它本质上不是一个具体的缓存实现方案（例如EHCache），而是一个对缓存使用的抽象和封装，通过在已有代码中打上几个预定义的注释，就可以实现希望达到的缓存效果。SpringCache支持跟第三方缓存例如EHCache、Redis集成；另外也提供了开箱即用的默认实现，可以直接拿来使用。SpringCache支持使用SpEL（Spring Expression Language）来定义缓存的key和各种condition，因此具备相当的灵活性，并可以支持非常复杂的语义。

1、新建项目sc-redis-cache，对用的pom.xml文件如下

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>spring-cloud</groupId>
	<artifactId>sc-redis-cache</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>sc-redis-cache</name>
	<url>http://maven.apache.org</url>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.4.RELEASE</version>
	</parent>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>Finchley.RELEASE</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>

		</dependencies>
	</dependencyManagement>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<maven.compiler.source>1.8</maven.compiler.source>
		<maven.compiler.target>1.8</maven.compiler.target>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-redis</artifactId>
		</dependency>
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-pool2</artifactId>
		</dependency>

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

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

		<dependency>
			<groupId>com.zaxxer</groupId>
			<artifactId>HikariCP</artifactId>
		</dependency>

		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>6.0.3</version>
		</dependency>


		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis-spring</artifactId>
			<version>1.3.2</version>
		</dependency>

		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.3.2</version>
		</dependency>

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

2、新建springboot启动类RedisCacheApplication.java

package sc.redis.cache;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;

/**
 * 更多资源关注公众号： java乐园
 * 
 * @author Administrator
 *
 */
@SpringBootApplication
@EnableCaching // 启动缓存
@MapperScan(basePackages="sc.redis.cache.dao")
public class RedisCacheApplication {

	public static void main(String[] args) {
		SpringApplication.run(RedisCacheApplication.class, args);
	}

}

备注：@MapperScan(basePackages="sc.redis.cache.dao")该注解的basePackages一定是DAO所在包最终报名。如果写成@MapperScan(basePackages="sc.redis.cache ")这样在测试中将报错： 3、新建配置文件application.yml

server:
	port: 9003

spring:
	application:
		name: sc-redis-cache
	datasource:
		driverClassName: com.mysql.jdbc.Driver
		url: jdbc:mysql://localhost:3306/sc?serverTimezone=UTC&useUnicode=true&characterEncoding=UTF-8
		username: root
		password: root
		type: com.zaxxer.hikari.HikariDataSource
		hikari:
			minimum-idle: 5
			maximum-pool-size: 15
			auto-commit: true
			idle-timeout: 30000
			pool-name: DatebookHikariCP
			max-lifetime: 1800000
			connection-timeout: 30000
			connection-test-query: SELECT 1
	cache:
		type: REDIS
		redis:
			timeToLive: 200000 #缓存超时时间ms
			cache-null-values: false #是否缓存空值
	redis:
		host: 127.0.0.1
		password: 
		port: 6379
		timeout: 10000 # 连接超时时间（毫秒）
		database: 0 # Redis默认情况下有16个分片，这里配置具体使用的分片，默认是0
		lettuce:
			pool:
				max-active: 8 # 连接池最大连接数（使用负值表示没有限制） 默认 8
				max-wait: -1 # 连接池最大阻塞等待时间（使用负值表示没有限制） 默认 -1
				max-idle: 8 # 连接池中的最大空闲连接 默认 8
				min-idle: 0 # 连接池中的最小空闲连接 默认 0

logging:
	level:
		sc.redis.cache.dao: debug

备注：配置文件中有连接数据库的配置信息和连接redis的配置信息，同时配置了打印sql语句的日志级别

4、新建自定义reids序列化方式RedisCacheSerializeConfiguration.java类

package sc.redis.cache.config;

import java.time.Duration;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

@Configuration
public class RedisCacheSerializeConfiguration {

//	/**
//	 *二选一
//	 * 设置 redis 数据默认过期时间 设置@cacheable 序列化方式
//	 * 
//	 * @return
//	 */
//	@Bean
//	public RedisCacheConfiguration redisCacheConfiguration() {
//		RedisCacheConfiguration configuration = RedisCacheConfiguration.defaultCacheConfig();
//		configuration = configuration.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(valueSerializer()))
//				.entryTtl(Duration.ofDays(30));
//		configuration.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(keySerializer()));
//		return configuration;
//	}

	/**
	 * 二选一
	 * 设置 redis 数据默认过期时间 设置@cacheable 序列化方式
	 * 
	 * @param connectionFactory
	 * @return
	 */
	@Bean
	public RedisCacheManager cacheManager(RedisConnectionFactory connectionFactory) {
		RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofDays(30))
				.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(keySerializer()))
				.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(valueSerializer()))
				.disableCachingNullValues();
		RedisCacheManager redisCacheManager = RedisCacheManager.builder(connectionFactory).cacheDefaults(config)
				.transactionAware().build();
		System.out.println("自定义RedisCacheManager加载完成");
		return redisCacheManager;
	}

	private RedisSerializer<String> keySerializer() {
		return new StringRedisSerializer();
	}

	private RedisSerializer<Object> valueSerializer() {
		return new GenericJackson2JsonRedisSerializer();
	}

}

5、启动相关类请参照源码，目录结构如下 6、编写单元测试类

package sc.redis.cache;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import sc.redis.cache.model.User;
import sc.redis.cache.service.UserService;

@RunWith(SpringRunner.class)
@SpringBootTest
public class TestRedis {

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

	@Autowired
	private UserService userService;

	@Test
	public void add() {
		User u = new User();
		u.setId(4L);
		u.setUserName("huangjinjin");
		u.setPosition("cto");
		u.setAge(24);
		userService.addUser(u);

	}

	@Test
	public void get() {
		User u =userService.getUser(4L);
		logger.debug("userName = "+ u.getUserName());
	}
}

7、进行单元测试运行add方法添加一条数据到数据库：日志：