springboot中使用RedisTemplate实现redis数据缓存

SpringBoot 整合 Redis 数据库实现数据缓存的本质是整合 Redis 数据库，通过对需要“缓存”的数据存入 Redis 数据库中，下次使用时先从 Redis 中获取，Redis 中没有再从数据库中获取，这样就实现了 Redis 做数据缓存。   按照惯例，下面一步一步的实现 Springboot 整合 Redis 来存储数据，读取数据。

1. 项目添加依赖首页第一步还是在项目添加 Redis 的环境， Jedis。

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


	redis.clients
	jedis

    2. 添加redis的参数

spring: 
### Redis Configuration
  redis: 
    pool: 
      max-idle: 10
      min-idle: 5
      max-total: 20
    hostName: 127.0.0.1
    port: 6379

  3.编写一个 RedisConfig 注册到 Spring 容器

package com.config;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import redis.clients.jedis.JedisPoolConfig;

/**
 * 描述：Redis 配置类
 */
@Configuration
public class RedisConfig {
	/**
	 * 1.创建 JedisPoolConfig 对象。在该对象中完成一些连接池的配置
	 */
	@Bean
	@ConfigurationProperties(prefix="spring.redis.pool")
	public JedisPoolConfig jedisPoolConfig() {
		JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
		
		return jedisPoolConfig;
	}

	/**
	 * 2.创建 JedisConnectionFactory：配置 redis 连接信息
	 */
	@Bean
	@ConfigurationProperties(prefix="spring.redis")
	public JedisConnectionFactory jedisConnectionFactory(JedisPoolConfig jedisPoolConfig) {
		
		JedisConnectionFactory jedisConnectionFactory = new JedisConnectionFactory(jedisPoolConfig);
		
		return jedisConnectionFactory;
	}

	/**
	 * 3.创建 RedisTemplate:用于执行 Redis 操作的方法
	 */
	@Bean
	public RedisTemplate redisTemplate(JedisConnectionFactory jedisConnectionFactory) {
		
		RedisTemplate redisTemplate = new RedisTemplate<>();
		
		// 关联
		redisTemplate.setConnectionFactory(jedisConnectionFactory);
		// 为 key 设置序列化器
		redisTemplate.setKeySerializer(new StringRedisSerializer());
		// 为 value 设置序列化器
		redisTemplate.setValueSerializer(new StringRedisSerializer());
		
		return redisTemplate;
	}
}

4.使用redisTemplate

package com.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.bean.Users;

/**
* @Description 整合 Redis 测试Controller
* @version V1.0
*/
@RestController
public class RedisController {
	
	@Autowired
	private RedisTemplate redisTemplate;
	
	@RequestMapping("/redishandle")
	public String redishandle() {
		
		//添加字符串
		redisTemplate.opsForValue().set("author", "欧阳");
		
		//获取字符串
		String value = (String)redisTemplate.opsForValue().get("author");
		System.out.println("author = " + value);
		
		//添加对象
		//重新设置序列化器
		redisTemplate.setValueSerializer(new JdkSerializationRedisSerializer());
		redisTemplate.opsForValue().set("users", new Users("1" , "张三"));
		
		//获取对象
		//重新设置序列化器
		redisTemplate.setValueSerializer(new JdkSerializationRedisSerializer());
		Users user = (Users)redisTemplate.opsForValue().get("users");
		System.out.println(user);
		
		//以json格式存储对象
		//重新设置序列化器
		redisTemplate.setValueSerializer(new Jackson2JsonRedisSerializer<>(Users.class));
		redisTemplate.opsForValue().set("usersJson", new Users("2" , "李四"));
		
		//以json格式获取对象
		//重新设置序列化器
		redisTemplate.setValueSerializer(new Jackson2JsonRedisSerializer<>(Users.class));
		user = (Users)redisTemplate.opsForValue().get("usersJson");
		System.out.println(user);
		
		return "home";
	}
}

5.项目实战中redisTemplate的使用

/**
 * 
 */
package com.shiwen.lujing.service.impl;

import java.util.List;
import java.util.concurrent.TimeUnit;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.shiwen.lujing.dao.mapper.WellAreaDao;
import com.shiwen.lujing.service.WellAreaService;
import com.shiwen.lujing.util.RedisConstants;

/**
 * @author zhangkai
 *
 */
@Service
public class WellAreaServiceImpl implements WellAreaService {

	@Autowired
	private WellAreaDao wellAreaDao;

	@Autowired
	private RedisTemplate stringRedisTemplate;

	/*
	 * (non-Javadoc)
	 * 
	 * @see com.shiwen.lujing.service.WellAreaService#getAll()
	 */
	@Override
	public String getAll() throws JsonProcessingException {
		//redis中key是字符串
		ValueOperations opsForValue = stringRedisTemplate.opsForValue();
		//通过key获取redis中的数据
		String wellArea = opsForValue.get(RedisConstants.REDIS_KEY_WELL_AREA);
		//如果没有去查数据库
		if (wellArea == null) {
			List wellAreaList = wellAreaDao.getAll();
			wellArea = new ObjectMapper().writeValueAsString(wellAreaList);
			//将查出来的数据存储在redis中
			opsForValue.set(RedisConstants.REDIS_KEY_WELL_AREA, wellArea, RedisConstants.REDIS_TIMEOUT_1, TimeUnit.DAYS);
            // set(K key, V value, long timeout, TimeUnit unit)
            //timeout:过期时间；  unit:时间单位  
            //使用：redisTemplate.opsForValue().set("name","tom",10, TimeUnit.SECONDS);
            //redisTemplate.opsForValue().get("name")由于设置的是10秒失效，十秒之内查询有结
            //果，十秒之后返回为null 
		}
		return wellArea;
	}

}

6.redis中使用的key

package com.shiwen.lujing.util;

/**
 * redis 相关常量
 * 
 *
 */
public interface RedisConstants {

	/**
	 * 井首字
	 */
	String REDIS_KEY_JING_SHOU_ZI = "JING-SHOU-ZI";

	/**
	 * 井区块
	 */
	String REDIS_KEY_WELL_AREA = "WELL-AREA";

	/**
	 * 
	 */
	long REDIS_TIMEOUT_1 = 1L;

}