SpringBoot integrates Redis_study notes

Explanation: After SpringBoot 2.x, the original jedis used was replaced by lettuce
jedis: the direct connection used, if multiple threads are used, is unsafe. If you want to avoid unsafe, use the jedis pool connection pool, which is more like BIO mode
lettuce: Using netty, instances can be shared in multiple threads, and there is no thread insecurity. It can reduce thread data. More like NIO Moss

1. Build a springboot project, configure redis

All configuration classes of springboot have an automatic configuration class; RedisAutoConfiguration
The automatic configuration class will bind a xx.properties(RedisProperties) Configuration file, this configuration file is bound to application.properties

 @Bean
    @ConditionalOnMissingBean(   //可以自定义一个redisTemplate来替换这个默认的
        name = {
    
    "redisTemplate"}
    )
    public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
    
    
    // 默认的redisTemplate没有过多的设置,redis对象都是需要序列化的
    // 两个泛型都是Object的类型,后面使用需要强制转换成<String,Object>
        RedisTemplate<Object, Object> template = new RedisTemplate();
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

    @Bean
    @ConditionalOnMissingBean   //由于String是redis中最常用的类型,所以暗度提出来一个bean
    public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
    
    
        StringRedisTemplate template = new StringRedisTemplate();
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

• 1. Import dependencies

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

• 2. Configure the connection

spring.redis.host=127.0.0.1
spring.redis.port=6379

• 3. Test

    @Autowired
    private RedisTemplate redisTemplate;
    @Test
    void contextLoads() {
    
    

        redisTemplate.opsForValue().set("key1","binhaizhijun");
        System.out.println(redisTemplate.opsForValue().get("key1"));
    }

The opsForXxx() in redisTemplate can operate on different data types. The api and redis instructions are the same;
except for the basic operations, the commonly used methods can be directly operated through redisTemplate, such as morning and basic CRUD to
get the connection object of redis as follows :

        RedisConnection connection = redisTemplate.getConnectionFactory().getConnection();
        connection.flushAll();
        connection.flushDb();

2. Customize RedisTemplate

When redis is storing objects, if the object is not serialized, it will report an error Failed to serialize object using DefaultSerializer;
(usually the json string is stored in enterprise development); so the general entity class needs to implement the serialization interface;
Redis uses the jdk default by default Serialization method, if you need to change the serialization method, you need to customize

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

/**
 * @ProjectName: qun-redis
 * @Package: com.qun.config
 * @ClassName: RedisConfig
 * @Description: redisTemplate 序列化的配置类
 * @Author: 滨海之君
 * @CreateDate: 2021/3/2 22:06
 */
@Configuration
public class RedisConfig {
    
    
    @Bean
    @SuppressWarnings("all")
    public RedisTemplate<String,Object> redisTemplate(RedisConnectionFactory factory){
    
    
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
        // key采用String的序列化方式
        template.setKeySerializer(stringRedisSerializer);
        // hash的key采用String的序列化方式
        template.setHashKeySerializer(stringRedisSerializer);
        //value序列化方式采用jackson
        template.setValueSerializer(jackson2JsonRedisSerializer);
        // hash的value序列化方式采用jackson
        template.setHashValueSerializer(jackson2JsonRedisSerializer);
        template.afterPropertiesSet();
        return template;
    }
}