Redis 使用

使用思路

• 当获取数据时,应该先查询缓存,如果缓存中的数据为null,那么这时应该访问后台的数据库.
• 将查询到的数据转化为JSON数据(objectMapper),将JSON串存入redis中.
• 当获取数据时,这时缓存中有数据.将JSON串转化为java对象进行return返回.

测试

	@Test
    public void test04(){
        Jedis jedis = new Jedis("192.168.31.181", 6379);
        String username = "user02";
        String key = "USER_NAME_" + username;
        String result = jedis.get(key);
        List<User> userList;

        //模拟数据库数据
        List<User> data = new ArrayList<>();
        User user0 = new User();
        user0.setId(1);
        user0.setName("小明");
        user0.setAge(18);
        user0.setSex("男");
        User user1 = new User();
        user1.setId(1);
        user1.setName("小明");
        user1.setAge(18);
        user1.setSex("男");
        User user2 = new User();
        user2.setId(1);
        user2.setName("小明");
        user2.setAge(18);
        user2.setSex("男");


        data.add(user0);
        data.add(user1);
        data.add(user2);

        try {
            if (StringUtils.isEmpty(result)){

                userList = data;
                String userListJson = OBJECT_MAPPER.writeValueAsString(userList);
                jedis.set(key,userListJson);
                System.out.println("查询数据库");
                System.out.println(userList);
            }else {
              userList =  OBJECT_MAPPER.readValue(result, List.class);
              System.out.println("查询缓存");
              System.out.println(userList);
            }
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

将redis工具API Jedis交给spring容器管理

配置properties文件

redis.host=192.168.31.181
redis.port=6379

Spring 加载配置文件

	<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="locations">
			<!--Resource[] locations;  -->
			<list>
				<value>classpath:/property/redis.properties</value>
			</list>
		</property>
	</bean>

Spring容器整合Redis

	<bean class="redis.clients.jedis.Jedis" id="jedis">
		<constructor-arg name="host" value="${redis.host}"/>
		<constructor-arg name="port" value="${redis.port}"/>
	</bean>