1.pom引入依赖

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

2.配置redis的链接地址

如果是本地的话可以不配置（因为默认就配置了且端口是6379）
spring.redis.host=127.0.0.1

3.测试类写法

    @Autowired
    StringRedisTemplate stringRedisTemplate;//操作k-v都是字符串的
    @Autowired
    RedisTemplate redisTemplate;//k-v都是对象的
    @Test
    public void test1(){
        //给redis保存一个数据
//        stringRedisTemplate.opsForValue().append("mess","hello");
        String mess = stringRedisTemplate.opsForValue().get("mess");
        System.out.println(mess);
    }

4.将对象保存成json格式的

传统的方式。利用jar包把对象转成json
redis默认的序列化机制是用的jdk序列化器，可以自定义改成json序列化器

1>先自定义配置类-将employee这个对象设置默认序列化机制为json序列化器

@Configuration
public class MyRedisConfig {
    @Bean
    public RedisTemplate<Object, Employee> empRedisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<Object, Employee> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);
        Jackson2JsonRedisSerializer<Employee> serializer=new Jackson2JsonRedisSerializer<Employee>(Employee.class);
        template.setDefaultSerializer(serializer);
        return template;
    }
}

2>编写测试类<br />关键是用RedisTemplate<Object, Employee> employeeRedisTemplate;而不是之前的RedisTemplate redisTemplate;

    @Autowired
    RedisTemplate<Object, Employee> employeeRedisTemplate;
    @Test
    public void test1(){
        //给redis保存一个数据
//        stringRedisTemplate.opsForValue().append("mess","hello");
//        String mess = stringRedisTemplate.opsForValue().get("mess");
//        System.out.println(mess);
        //给redis保存一个json对象
        Employee employee= employeeDao.getEmpId(1);
        employeeRedisTemplate.opsForValue().set("emp-01",employee);
    }

效果如下：<br />![image.png](https://cdn.nlark.com/yuque/0/2021/png/22543923/1635067292759-d5d578e5-5599-42e7-ab68-6b38112d63cf.png#clientId=u2fb5e072-20bb-4&from=paste&height=215&id=u7acaec52&margin=%5Bobject%20Object%5D&name=image.png&originHeight=215&originWidth=654&originalType=binary&ratio=1&size=24440&status=done&style=none&taskId=u50222637-4ac2-4352-82d1-37d4d3937d6&width=654)

5.redis缓存

引入redis的starter之后，容器中保存的是RedisCacheManager;
RedisCacheManager帮我们创建RedisCache作为缓存组件（通过操作redis缓存数据）
保存对象的时候默认是jdk序列化方法，这里想改成json序列化器

原理就是RedisCacheManager创建RedisCache的时候用的是RedisTemplate，重构下RedisCacheManager就行（这是针对springboot1.x版本-在SpringBoot1.x中，RedisCacheManager是可以使用RedisTemplate作为参数注入的）
然后在service层绑定一下选用哪个管理器就行@CacheConfig( cacheNames=” emp” , cacheManager =”employeeCacheManager” )

@Bean
    public RedisTemplate<Object, Employee> empRedisTemplate(
            RedisConnectionFactory redisConnectionFactory)
            throws UnknownHostException {
        RedisTemplate<Object, Employee> template = new RedisTemplate<Object, Employee>();
        template.setConnectionFactory(redisConnectionFactory);
        Jackson2JsonRedisSerializer<Employee> ser = new Jackson2JsonRedisSerializer<Employee>(Employee.class);
        template.setDefaultSerializer(ser);
        return template;
    }
    @Bean
    public RedisTemplate<Object, Department> deptRedisTemplate(
            RedisConnectionFactory redisConnectionFactory)
            throws UnknownHostException {
        RedisTemplate<Object, Department> template = new RedisTemplate<Object, Department>();
        template.setConnectionFactory(redisConnectionFactory);
        Jackson2JsonRedisSerializer<Department> ser = new Jackson2JsonRedisSerializer<Department>(Department.class);
        template.setDefaultSerializer(ser);
        return template;
    }
    //CacheManagerCustomizers可以来定制缓存的一些规则
    @Primary  //将某个缓存管理器作为默认的
    @Bean
    public RedisCacheManager employeeCacheManager(RedisTemplate<Object, Employee> empRedisTemplate){
        RedisCacheManager cacheManager = new RedisCacheManager(empRedisTemplate);
        //key多了一个前缀
        //使用前缀，默认会将CacheName作为key的前缀
        cacheManager.setUsePrefix(true);
        return cacheManager;
    }
    @Bean
    public RedisCacheManager deptCacheManager(RedisTemplate<Object, Department> deptRedisTemplate){
        RedisCacheManager cacheManager = new RedisCacheManager(deptRedisTemplate);
        //key多了一个前缀
        //使用前缀，默认会将CacheName作为key的前缀
        cacheManager.setUsePrefix(true);
        return cacheManager;
    }

针对springboot2.x版本-有很大的不同，RedisCacheManager构造器已经无法再使用RedisTemplate进行构造
所以这边的写法是：RedisTemplate不需要重构，只需要重构CacheManager就OK了


@Configuration
public class MyRedisConfig  {
    @Bean
    public CacheManager cacheManager(RedisConnectionFactory factory) {
        RedisSerializer<String> redisSerializer = new StringRedisSerializer();
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        //解决查询缓存转换异常的问题
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.activateDefaultTyping(LaissezFaireSubTypeValidator.instance , ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        // 配置序列化（解决乱码的问题）
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ofDays(1))//设置过期时间
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
                .disableCachingNullValues();
        RedisCacheManager cacheManager = RedisCacheManager.builder(factory)
                .cacheDefaults(config)
                .build();
        return cacheManager;
    }
}

效果如下：

具体怎么写缓存注解的话，参考：https://www.yuque.co m/feiyiyangdebiancheng/kb/adove4
扩展：用编码的方式使用缓存：

Java 知识点

springboot整合redis缓存

1.pom引入依赖

2.配置redis的链接地址

3.测试类写法

4.将对象保存成json格式的

5.redis缓存