Springboot使用redis,以及解决redis缓存穿透,击穿,雪崩等问题

时间:2024-10-01 07:45:13

1.Redis面试题-缓存穿透,缓存击穿,缓存雪崩

1 穿透: 两边都不存在(皇帝的新装) (返回空值)(互斥锁)(黑名单) (布隆过滤器)

2 穿:一个或多个热点的key失效了,这时大量的并发请求直接到达数据库. (提前预热

3 雪崩:大量key同时失效 (避免大量的key同一时间失效,错峰

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2.Spring是如何集成Redis的?

Spring Data Redis

 <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-redis</artifactId>

 </dependency> <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-pool2</artifactId>
 </dependency>

3.高级封装

4.Redis配置

Spring.Redis常用配置参数有哪些。

# Redis服务器地址
spring.redis.host=10.1.30.222
# Redis数据库索引(默认为0)
spring.redis.database=0 
# Redis服务器连接端口
spring.redis.port=6379 
# Redis服务器连接密码(默认为空)
#spring.redis.password=
## 连接超时时间(毫秒)
spring.redis.timeout=30000
# 连接池最大连接数(使用负值表示没有限制) 默认 8
spring.redis.lettuce.pool.max-active=8
# 连接池中的最大空闲连接 默认 8
spring.redis.lettuce.pool.max-idle=8
# 连接池中的最小空闲连接 默认 0
spring.redis.lettuce.pool.min-idle=1
#连接池中最大空闲等待时间,3s没有活干的时候直接驱逐该链接
spring.redis.lettuce.pool.min-evictable-idle-time-millis = 3000
# 连接池最大阻塞等待时间(使用负值表示没有限制) 默认 -1
spring.redis.lettuce.pool.max-wait=-1

5.StringRedisTemplate

String



    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    private final String key = "zhengzhou";

    public void test() {

        stringRedisTemplate.opsForValue().set(key, "我的家乡", 30, TimeUnit.SECONDS);
        String value = stringRedisTemplate.opsForValue().get(key);
        System.out.println(value);
    }


Hash



    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    private  final  String key ="zhouxingxing";
    public void  test(){
        stringRedisTemplate.opsForHash().put(key,"20220325","郑州");
        stringRedisTemplate.opsForHash().put(key,"20220326","洛阳");

        List<Object> values = stringRedisTemplate.opsForHash().values(key);

        for (Object value:values){
            System.out.println(value);
        }

    }

List


    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    private  final  String key ="onewayroad";
    void  test(){

        stringRedisTemplate.opsForList().leftPush(key,"周星星");
        stringRedisTemplate.opsForList().leftPush(key,"张敏");
        stringRedisTemplate.opsForList().leftPush(key,"李大锤");
        String value = stringRedisTemplate.opsForList().rightPop(key);
        System.out.println(value);


    }
}
    @Test
    void test6() {
     // 如果一些原生命令,spring 没有给我们封装,redisTemplate.execute(new RedisCallback)
    while (true){
        System.out.println("开始一轮监听");
        List<byte[]> rawResults = redisTemplateProduct.execute(new RedisCallback<List<byte[]>>() {
            @Override
            public List<byte[]> doInRedis(RedisConnection connection) throws DataAccessException {
                return connection.bRPop(5,"product.hot".getBytes());
            }
        });
        if(ObjUtil.isNotEmpty(rawResults)){
            byte[] rawKey = rawResults.get(0);
            byte[] rawValue = rawResults.get(1);
            Product product = (Product)redisTemplateProduct.getValueSerializer().deserialize(rawValue);
            System.out.println(product);
        }
    }


Set

@Component
public class SetDemo {
    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    private final  String zhouxingxing ="zhouxingxing";
    private  final  String zhangmin = "zhangming";

    public void  test(){
        //添加周星星同学感兴趣的科目
        stringRedisTemplate.opsForSet().add(zhouxingxing,"语文");
        stringRedisTemplate.opsForSet().add(zhouxingxing,"数学");
        stringRedisTemplate.opsForSet().add(zhouxingxing,"数学");
        //添加张敏同学感兴趣的科目
        stringRedisTemplate.opsForSet().add(zhangmin,"数学");
        stringRedisTemplate.opsForSet().add(zhangmin,"英语");

        //获取两位同学共同感兴趣的科目
        Set<String> values = stringRedisTemplate.opsForSet().intersect(zhouxingxing, zhangmin);

        System.out.println("周星星和张敏共同感兴趣的科目为:");

        for(String value : values){
            System.out.println(value);
        }
        
    }
}

ZSet

@Component
public class ZSetDemo {
    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    private final  String key ="zhouxingxing";
    public void  test(){
        //添加周星星同学成绩
        stringRedisTemplate.opsForZSet().add(key,"语文",98);
        stringRedisTemplate.opsForZSet().add(key,"数学",87);
        stringRedisTemplate.opsForZSet().add(key,"英语",75);
        //获取分数最高的成绩
        ZSetOperations.TypedTuple<String> values = stringRedisTemplate.opsForZSet().popMax(key);
        //打印值
        System.out.println("周星星最好成绩科目是:"+values.getValue());
        System.out.println("周星星最好成绩:"+values.getScore());
        
    }
}

6.RedisTemplate<T,V>泛型约束

6.1泛型约束的使用

@Component
public class RedisTemplateDemo {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;


    @Resource
    private RedisTemplate<String, User> redisTemplate;

    @Resource(name="redisTemplate")
    private ValueOperations<String,User> valueOperations;

    private final String key = "useris#01";

    public void test() {
        User user = User.builder().id(1).name("李四").build();
        redisTemplate.opsForValue().set(key,user );
        User value = redisTemplate.opsForValue().get(key);
        valueOperations.set(key,user );
        User value2 = valueOperations.get(key);
        System.out.println(value);

    }
}

6.2乱码的问题

        JdkSerializationRedisSerializer  serializer = new JdkSerializationRedisSerializer();
        byte[] serialize = serializer.serialize("user.01");
        System.out.println(new String(serialize));

6.3自定义序列化工具

@Configuration
public class RedisConfig {
    

       @Bean
    public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<Object, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);

        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper objectMapper = new ObjectMapper();
        // 序列化的时候,自动推断类型,将类型信息作为属性写入JSON
        // 反序列化时候,根据类型的全类名,序列化成对应的对象实例
        objectMapper.activateDefaultTyping(objectMapper.getPolymorphicTypeValidator(), ObjectMapper.DefaultTyping.NON_FINAL);

        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        //普通key序列化工具
        template.setKeySerializer(RedisSerializer.string());
        template.setValueSerializer(jackson2JsonRedisSerializer);
        //hash 小key 序列化工具
        template.setHashKeySerializer(RedisSerializer.string());
        template.setHashValueSerializer(jackson2JsonRedisSerializer);
        return template;
    }


}

7. 直接使用ListOperations、ValueOperations、SetOperations、ZSetOperations、HashOperations接口

在Spring Data Redis中,提供了丰富的模板操作接口,

ListOperationsValueOperationsSetOperationsZSetOperationsHashOperations

这些都是RedisTemplate的子接口,用于针对不同类型的Redis数据结构进行操作

REDIS 注释 redistemplate注入_mob6454cc6f4a4e的技术博客_51CTO博客