Redis使用（+Springboot）

1. 背景：将主页的目录放入Redis，加快访问速度，减轻数据库压力，并测试redis和mysql之间的查询速度差距

/**
 * 

 * TODO 菜单Service
 * 
 *
 * @author ainy
 * @version 2019年7月30日
 */
@Service("menuService")
public class MenuServiceImpl implements IMenuService {
	@Autowired
	private MenuMapper mapper;
	@Autowired
	private RedisTemplate<String, String> redisTemplate;
	
	private  final static String SYSTEM_REDISKEY_ALLMENU="allMenu";
	/* 
	 * 
	 */
	@Override
	public List<MenuEntity> getAllMenuList() {
		ValueOperations<String, String> opsForValue = redisTemplate.opsForValue();
		boolean hasKey = redisTemplate.hasKey(SYSTEM_REDISKEY_ALLMENU);
		if(hasKey) {
			long start = System.currentTimeMillis();
			 String string = opsForValue.get(SYSTEM_REDISKEY_ALLMENU);
			long end = System.currentTimeMillis();
			 System.out.println("查询redis花费的时间是:" + (end - start)+"s");
			 List<MenuEntity> parseArray = JSON.parseArray(string, MenuEntity.class);
			 return parseArray;
			
		}else {
			MenuEntityExample example = new MenuEntityExample();
			long start = System.currentTimeMillis();
			example.setDistinct(false);
			List<MenuEntity> allMneuList = mapper.selectByExample(example);
			long end = System.currentTimeMillis();
			System.out.println("查询mysql花费的时间是:" + (end - start)+"s");
			String jsonString = JSON.toJSONString(allMneuList);
			opsForValue.set(SYSTEM_REDISKEY_ALLMENU, jsonString, 5, TimeUnit.HOURS);
			return allMneuList;
			
		}
	}

2. 结果