RedisTemplate 使用

package org.spring.springboot.service.impl;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.spring.springboot.dao.CityDao;
import org.spring.springboot.domain.City;
import org.spring.springboot.service.CityService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;

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

/**
* 城市业务逻辑实现类
* <p>
* Created by bysocket on 07/02/2017.
*/
@Service
public class CityServiceImpl implements CityService {

private static final Logger LOGGER = LoggerFactory.getLogger(CityServiceImpl.class);

@Autowired
private CityDao cityDao;

@Autowired
private RedisTemplate redisTemplate;

/**
* 获取城市逻辑：
* 如果缓存存在，从缓存中获取城市信息
* 如果缓存不存在，从 DB 中获取城市信息，然后插入缓存
*/
public City findCityById(Long id) {
// 从缓存中获取城市信息
String key = "city_" + id;
ValueOperations<String, City> operations = redisTemplate.opsForValue();

// 缓存存在
boolean hasKey = redisTemplate.hasKey(key);
if (hasKey) {
City city = operations.get(key);

LOGGER.info("CityServiceImpl.findCityById() : 从缓存中获取了城市 >> " + city.toString());
return city;
}

// 从 DB 中获取城市信息
City city = cityDao.findById(id);

// 插入缓存
operations.set(key, city, 10, TimeUnit.SECONDS);
LOGGER.info("CityServiceImpl.findCityById() : 城市插入缓存 >> " + city.toString());

return city;
}

@Override
public Long saveCity(City city) {
return cityDao.saveCity(city);
}

/**
* 更新城市逻辑：
* 如果缓存存在，删除
* 如果缓存不存在，不操作
*/
@Override
public Long updateCity(City city) {
Long ret = cityDao.updateCity(city);

// 缓存存在，删除缓存
String key = "city_" + city.getId();
boolean hasKey = redisTemplate.hasKey(key);
if (hasKey) {
redisTemplate.delete(key);

LOGGER.info("CityServiceImpl.updateCity() : 从缓存中删除城市 >> " + city.toString());
}

return ret;
}

@Override
public Long deleteCity(Long id) {

Long ret = cityDao.deleteCity(id);

// 缓存存在，删除缓存
String key = "city_" + id;
boolean hasKey = redisTemplate.hasKey(key);
if (hasKey) {
redisTemplate.delete(key);

LOGGER.info("CityServiceImpl.deleteCity() : 从缓存中删除城市 ID >> " + id);
}
return ret;
}

}