Spring Boot从入门到精通（六）集成Redis实现缓存机制

Redis（Remote Dictionary Server )，即远程字典服务，是一个开源的使用ANSI C语言编写、支持网络、可基于内存亦可持久化的日志型、Key-Value数据库，并提供多种语言的API。

Redis是一个高性能的key-value内存数据库，通常被称为数据结构服务器，因为值可以是字符串、哈希、列表、集合和有序集合等类型，在如今系统不断追求高并发、高效率的大环境下，Redis被广泛使用。

本文在前一篇“Spring Boot从入门到精通（四）连接MySQL数据库（附源码）”文章中的项目源码基础上（关注“Java精选”微信公众号，切换至后台->聚合->开源项目，可以查看Spring Boot系列框架从入门到精通教程）。

通过查询MySQL数据库中表数据存储到Redis缓存中，之后再使用Redis查询数据返回参数呈现到浏览器上，利用Spring Boot框架集成Redis实现缓存机制，分享给大家参考和学习。

  Maven项目pom.xml文件在Spring Boot项目中pom.xml文件配置信息如下：

<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3..M2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.yoodb</groupId>
    <artifactId>springboot-study-demo04</artifactId>
    <version>0.0.-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>springboot-study-demo04</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.0.</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</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-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.xmlunit</groupId>
            <artifactId>xmlunit-core</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/**</include>
                </includes>
            </resource>
        </resources>
    </build>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </pluginRepository>
    </pluginRepositories>

</project>

MySQL数据库数据源类文件

创建名为DataSourceConfig的类，上一篇已经针对该内容详细介绍，在这里就不过多解释了，如果大家有什么不明白可以翻看以前记录【微信公众号“Java精选”，Spring Boot从入门到精通系列文章】，具体代码如下：

package com.yoodb.study.demo04.datasource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.yoodb.study.demo04.mapper", sqlSessionFactoryRef = "sqlSessionFactory")
public class DataSourceConfig {
    @Bean(name = "dataSource")
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource getDateSourceOne() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "sqlSessionFactory")
    @Primary
    public SqlSessionFactory oneSqlSessionFactory(@Qualifier("dataSource") DataSource datasource)
            throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(datasource);
        bean.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/*.xml"));
        return bean.getObject();
    }

    @Bean("sqlSessionTemplate")
    @Primary
    public SqlSessionTemplate sqlsessiontemplate(
            @Qualifier("sqlSessionFactory") SqlSessionFactory sessionfactory) {
        return new SqlSessionTemplate(sessionfactory);
    }
}

Redis缓存类文件

创建RedisConfig配置类，具体代码如下：

package com.yoodb.study.demo04.datasource;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;

@Configuration
public class RedisConfig extends CachingConfigurerSupport {

    @Bean("redisTemplate")
    @ConfigurationProperties(prefix="spring.redis")
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory){
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(factory);

        //将key的序列化设置成StringRedisSerializer
        StringRedisSerializer keySerializer = new StringRedisSerializer();
        redisTemplate.setKeySerializer(keySerializer);
        redisTemplate.setHashKeySerializer(keySerializer);

        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }

}

注：在添加RedisConfig配置时，因为连接redis需要RedisConnection和RedisConnectionFactory，RedisConnection是通过RedisConnectionFactory进行创建。

  实体类文件

新增BootUser实体类文件，具体代码如下：

package com.yoodb.study.demo04.bean;

import java.io.Serializable;

public class BootUser implements Serializable {
    private String id;
    private String name;
    private String detail;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDetail() {
        return detail;
    }

    public void setDetail(String detail) {
        this.detail = detail;
    }
}

新增mapper接口类文件

mapper接口类文件，具体代码如下：

package com.yoodb.study.demo04.mapper;
import com.yoodb.study.demo04.bean.BootUser;
import java.util.List;
public interface BootUserMapper {
    List<BootUser> selectAll();
}

新增mapper xml文件

在src/main/resources/mapper/（不存在文件加新建）创建BootUserMapper.xml文件，具体配置信息如下：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.yoodb.study.demo04.mapper.BootUserMapper" >
    <resultMap id="BaseResultMap" type="com.yoodb.study.demo04.bean.BootUser" >
        <id column="id" property="id" jdbcType="VARCHAR" />
        <result column="user_name" property="name" jdbcType="VARCHAR" />
        <result column="detail" property="detail" jdbcType="VARCHAR" />
    </resultMap>

    <select id="selectAll" resultMap="BaseResultMap">
    select
         id, user_name, detail
    from boot_user order by detail asc
    </select>
</mapper>

application.properties文件

在application.properties文件中增加MySQL数据库连接配置和Redis缓存连接配置参数，参考信息如下：

#MySQL
spring.datasource.jdbc-url=jdbc:mysql://123.57.47.154:3306/dba
spring.datasource.username=root
spring.datasource.password=wangyoodb
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.max-idle=
spring.datasource.max-wait=
spring.datasource.min-idle=
spring.datasource.initial-size=

#Redis
#Redis数据库索引（默认为0）
spring.redis.database=
#Redis服务器地址
spring.redis.host=127.0.0.1
#Redis服务器连接端口
spring.redis.port=

注：其中spring.redis.database参数的配置通常使用0即可，Redis在配置的时候可以设置数据库数量，默认为16个，可以理解为数据库的schema。

  创建service类文件

新增文件名BootUserService类文件，具体代码如下：

package com.yoodb.study.demo04.service;

import java.util.List;

import com.yoodb.study.demo04.bean.BootUser;
import com.yoodb.study.demo04.mapper.BootUserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

@Service
public class BootUserService {

    @Autowired
    private BootUserMapper bootUserMapper;

   @Autowired
    private RedisTemplate redisTemplate;

    public List<BootUser> getUsers(){
        List<BootUser> bootUsers = bootUserMapper.selectAll();
        redisTemplate.opsForValue().set("bootUsers",bootUsers);
        List<BootUser> list = (List<BootUser>)redisTemplate.opsForValue().get("bootUsers");
        return list;
    }

}

创建controller类文件

新增文件名BootUserController类文件，具体代码如下：

package com.yoodb.study.demo04;

import java.util.List;

import com.yoodb.study.demo04.bean.BootUser;
import com.yoodb.study.demo04.service.BootUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/myt")
public class BootUserController {
    @Autowired
    private BootUserService service;

    @RequestMapping("/getUsers")
    public List<BootUser> getUsers() {
        List<BootUser> list = service.getUsers();
        return list;
    }

}

 mapper的接口、xml文件及实体文件、service层、controller层创建完成后，目录如图：

  项目启动

项目启动后访问请求地址：

http://localhost:8080/myt/getUsers

通过浏览器访问输出如下信息：

[{"id":"","name":"admin","detail":"欢迎关注“Java精选”微信公众号，专注程序员推送一些Java开发知识，包括基础知识、各大流行框架（Mybatis、Spring、Spring Boot等）、大数据技术（Storm、Hadoop、MapReduce、Spark等）、数据库（Mysql、Oracle、NoSQL等）、算法与数据结构、面试专题、面试技巧经验、职业规划以及优质开源项目等。其中一部分由小编总结整理，另一部分来源于网络上优质资源，希望对大家的学习和工作有所帮助。"}]

Spring Boot从入门到精通（六）集成Redis实现缓存机制（项目源码springboot-study-demo04）地址：

https://github.com/yoodb/springboot

到此讲完了，Spring Boot集成Redis实现缓存机制，实际上就这么简单。不过需要注意使用的时候遇到的坑。～～