在项目中加入redis缓存（学习总结）

首先加入依赖

  

        
        
            org.springframework.boot
            spring-boot-starter-data-redis
        

        
        
            org.apache.commons
            commons-pool2
            2.6.0
        

    

 在配置文件中加入redis配置

这里要注意如果redis设置了密码要加上

spring.redis.password=*****

*****代表你redis设置的密码

 如果链接不上

有可能是因为你的redis没开启

开启redis

输入命令查看开启redis没有

ps -ef | grep redis

如果还链接不上redis 可能是防火墙原因

输入命令关闭防火墙

systemctl stop firewalld

如果仍然链接不上

可能是redis端口未开放

去宝塔页面开放，这里就不做演示了

spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
spring.jackson.time-zone=GMT+8
spring.redis.host=8.130.169.21
spring.redis.port=6379
spring.redis.database= 0
spring.redis.timeout=1800000
spring.redis.password=*****
spring.redis.lettuce.pool.max-active=20
spring.redis.lettuce.pool.max-wait=-1
#最大阻塞等待时间(负数表示没限制)
spring.redis.lettuce.pool.max-idle=5
spring.redis.lettuce.pool.min-idle=0

在config包中中加入redis的配置

package com.atguigu.yygh.common.config;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.KeyGenerator;
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.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;


import java.lang.reflect.Method;
import java.time.Duration;

@Configuration
@EnableCaching
public class RedisConfig {

    
    @Bean
    public KeyGenerator keyGenerator() {
        return new KeyGenerator() {
            @Override
            public Object generate(Object target, Method method, Object... params) {
                StringBuilder sb = new StringBuilder();
                sb.append(target.getClass().getName());
                sb.append(method.getName());
                for (Object obj : params) {
                    sb.append(obj.toString());
                }
                return sb.toString();
            }
        };
    }

    
    @Bean
    public RedisTemplate redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);

//解决查询缓存转换异常的问题
        ObjectMapper om = new ObjectMapper();
// 指定要序列化的域，field,get和set,以及修饰符范围，ANY是都有包括private和public
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
// 指定序列化输入的类型，类必须是非final修饰的，final修饰的类，比如String,Integer等会跑出异常
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);

//序列号key value
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);

        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }

    
    @Bean
    public CacheManager cacheManager(RedisConnectionFactory factory) {
        RedisSerializer redisSerializer = new StringRedisSerializer();
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);

//解决查询缓存转换异常的问题
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);

// 配置序列化（解决乱码的问题）,过期时间600秒
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ofSeconds(600))
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
                .serializevaluesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
                .disableCachingNullValues();

        RedisCacheManager cacheManager = RedisCacheManager.builder(factory)
                .cacheDefaults(config)
                .build();
        return cacheManager;
    }
}

在service层中配置要缓存的数据

package com.atguigu.yygh.cmn.service.impl;

import com.alibaba.excel.EasyExcel;
import com.atguigu.yygh.cmn.listener.DictListener;
import com.atguigu.yygh.cmn.mapper.DictMapper;
import com.atguigu.yygh.cmn.service.DictService;
import com.atguigu.yygh.model.cmn.Dict;
import com.atguigu.yygh.vo.cmn.DictEeVo;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.beans.BeanUtils;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
@Component
public class DictServiceImpl extends ServiceImpl implements DictService {
    @CacheEvict(value = "dict", allEntries=true)
    @Override
    public void importData(MultipartFile file) {
        try {
            EasyExcel.read(file.getInputStream(),DictEeVo.class,new DictListener(baseMapper)).sheet().doRead();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    @Cacheable(value = "dict",keyGenerator = "keyGenerator")
    @Override
    public List findChildData(Long id) {
        QueryWrapper wrapper=new QueryWrapper<>();
        wrapper.eq("parent_id",id);
        List dictList = baseMapper.selectList(wrapper);
        for (Dict dict : dictList) {
            Long dictId = dict.getId();
            boolean isChild = this.isChild(dictId);
            dict.setHasChildren(isChild);
        }
        return dictList;
    }

    @Override
    public void exportData(HttpServletResponse response) {
        try {
            response.setContentType("application/vnd.ms-excel");
            response.setCharacterEncoding("utf-8");
    // 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系
            String fileName = URLEncoder.encode("数据字典", "UTF-8");
            response.setHeader("Content-disposition", "attachment;filename="+ fileName + ".xlsx");

            List dictList = baseMapper.selectList(null);
            List dictVoList = new ArrayList<>(dictList.size());
            for(Dict dict : dictList) {
                DictEeVo dictVo = new DictEeVo();
                BeanUtils.copyProperties(dict, dictVo, DictEeVo.class);
                dictVoList.add(dictVo);
            }

            EasyExcel.write(response.getOutputStream(), DictEeVo.class).sheet("数据字典").doWrite(dictVoList);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    //判断ID下面是否有子节点
    public boolean isChild(Long id){
        QueryWrapper wrapper=new QueryWrapper<>();
        wrapper.eq("parent_id",id);
        Integer count = baseMapper.selectCount(wrapper);
        return count>0;
    }
}