springboot之整合redis

作者: crishawy | 来源:发表于2018-05-29 22:38 被阅读180次

缓存应用场景

什么是缓存?
在互联网场景下,尤其 2C 端大流量场景下,需要将一些经常展现和不会频繁变更的数据,存放在存取速率更快的地方。缓存就是一个存储器,在技术选型中,常用 Redis 作为缓存数据库。缓存主要是在获取资源方便性能优化的关键方面
缓存的应用场景有哪些呢?
比如常见的电商场景,根据商品 ID 获取商品信息时,店铺信息和商品详情信息就可以缓存在 Redis,直接从 Redis 获取。减少了去数据库查询的次数。但会出现新的问题,需要对缓存进行更新,防止数据读入错误


image.png

Redis在CENTOS7中安装

daemonize设置为yes,设置为后台启动


image.png

运行在主机ip,端口6379地址

springboot整合redis-使用Jedis客户端

创建springboot工程

工程目录如下

image.png

pom文件

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.enowsh.springboot_redis</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>ch.qos.logback</groupId>
                    <artifactId>logback-classic</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>ch.qos.logback</groupId>
                    <artifactId>logback-classic</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.9</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>3.4.2</version>
        </dependency>
        <dependency>
            <groupId>redis.clients</groupId>
            <artifactId>jedis</artifactId>
            <version>2.9.0</version>
        </dependency>
        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>


    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

注意:要在两个地方去掉logback-classic包,不然会报错

springboot整合mybatis

引入mapper文件,配置数据源以及mybatis等的配置,此处不再赘述

配置Jedis客户端

application.properties设置redis的属性

#redis配置
redis.host=192.168.73.128
redis.port=6379
#用户缓存key配置
REDIS_USER_KEY=REDIS_USER_KEY

写config类,配置Jedis

package com.enowsh.springboot_redis.config.redis;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

/**
 * @author:wong
 */
@Configuration
public class RedisConfig {

    @Value("${redis.host}")
    private String host;

    @Value("${redis.port}")
    private int port;

    @Bean
    public JedisPool jedisPool(){
        JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
        JedisPool jedisPool = new JedisPool(jedisPoolConfig, host, port);
        return jedisPool;
    }

    @Bean
    public Jedis jedis(){
        Jedis jedis = jedisPool().getResource();
        return jedis;
    }
}

注意点:

  • 使用@Value注解引入属性
  • 创建JedisPool的bean,初始化构造函数参数,分别是:JedisPoolConfig对象,主机地址,端口号
  • 为了使用方便,配置Jedis的bean

编写service测试

package com.enowsh.springboot_redis.service.impl;

import com.enowsh.springboot_redis.mapper.PmsUserMapper;
import com.enowsh.springboot_redis.pojo.PmsResult;
import com.enowsh.springboot_redis.pojo.PmsUser;
import com.enowsh.springboot_redis.service.UserService;
import com.enowsh.springboot_redis.utils.JsonUtils;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import redis.clients.jedis.Jedis;

import java.util.Date;

/**
 * @author:wong
 */
@Service
@Transactional //默认开启所有public方法的事务
public class UserServiceImpl implements UserService {
    @Autowired
    private PmsUserMapper pmsUserMapper;

    @Autowired
    private Jedis jedis;

    @Value("${REDIS_USER_KEY}")
    private String REDIS_USER_KEY;

    @Override
    public PmsResult getUserById(long id) {
        //添加查询缓存逻辑
        try {
            String s = jedis.hget(REDIS_USER_KEY,id+"");
            if (!StringUtils.isBlank(s)){
                PmsUser pmsUser=JsonUtils.jsonToPojo(s,PmsUser.class);
                return PmsResult.ok(pmsUser);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        PmsUser pmsUser = pmsUserMapper.selectByPrimaryKey(id);
        if (pmsUser==null)
            return PmsResult.build(400,"未查询到用户");
        else {
            //添加写入缓存逻辑,将用户信息写入缓存,以json串的模式写入
            try {
                jedis.hset(REDIS_USER_KEY ,id+"", JsonUtils.objectToJson(pmsUser));
                //设置用户信息有效期,一天过期
                jedis.expire(REDIS_USER_KEY ,86400);
            }catch (Exception e){
                e.printStackTrace();
            }
            return PmsResult.ok(pmsUser);
        }
    }

    @Override
    public PmsResult getUserByIdentity(int identity) {
        return null;
    }

    @Override
    public PmsResult addUser(PmsUser user) {
        //添加删除缓存逻辑,问题是如何删除一类用户
        try{
            jedis.del(REDIS_USER_KEY);
        }catch (Exception e){
            e.printStackTrace();
        }
        if (user==null)
            return PmsResult.build(400,"用户为空");
        Date date=new Date();
        user.setCreated(date);
        user.setUpdated(date);
        pmsUserMapper.insert(user);
        return PmsResult.ok();
    }

    @Override
    public PmsResult testRedis() {
        String a = jedis.get("a");
        return PmsResult.ok(a);
    }

    @Override
    public PmsResult deleteUserById(long id) {
        return null;
    }

    @Override
    public PmsResult updateUser(PmsUser user) {
        return null;
    }
}

测试点:

  • 查询数据:先从缓存中查询,如果命中,则返回数据,如果未命中,则从数据库中查询,并将数据写入缓存。此处写缓存使用Jedis的hset方法,利于统一规划管理
  • 操作数据:操作数据时,为了防止更新后还是读缓存原来的数据,导致错误,需要清空缓存

controller

package com.enowsh.springboot_redis.controller;

import com.enowsh.springboot_redis.pojo.PmsResult;
import com.enowsh.springboot_redis.pojo.PmsUser;
import com.enowsh.springboot_redis.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;


/**
 * @author:wong
 */
@Controller
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;

    @RequestMapping("/find/{id}")
    @ResponseBody
    public PmsResult findUserById(@PathVariable long id){
        PmsResult pmsResult= userService.getUserById(id);
        return pmsResult;
    }

    @RequestMapping("/test/redis")
    @ResponseBody
    public PmsResult testRedis(){
        PmsResult pmsResult = userService.testRedis();
        return pmsResult;
    }

    @RequestMapping(value = "/add",method = RequestMethod.POST)
    @ResponseBody
    public PmsResult addUser(PmsUser user,String username){
        PmsResult pmsResult = userService.addUser(user);
        return pmsResult;
    }
}

测试结果

get请求:http://localhost:8080/user/find/44

image.png
缓存 :
image.png
post请求:http://localhost:8080/user/add
image.png
缓存:
image.png

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