Exception when introducing redistemplate: noclassdeffounderror: com/fasterxml/jackson/core/jsonprocessingexception

Abnormal scenario

I want to test one today RedisTemplate The problem of , So use Spring Initializr Created a Spring Boot project , And introduced Spring Data Redis.

pom The corresponding package will be introduced to me in the file ：

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

Customize RedisTemplate To configure , Set up Value The serialization method is GenericJackson2JsonRedisSerializer

@Configuration
public class RedisTemplateConfig {
    

    @Bean
    public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
    
        RedisTemplate<Object, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());
        return redisTemplate;
    }
}

Start the project after simple configuration , Direct prompt can't find Jackson Exceptions of related classes ：java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonProcessingException

Some error logs are intercepted below

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'redisTemplate' defined in class path resource [com/example/redistemplatesourcecodedemo/config/RedisTemplateConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.redis.core.RedisTemplate]: Factory method 'redisTemplate' threw exception; nested exception is java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonProcessingException
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658)

resolvent

Looked at the spring-boot-starter-data-redis Of pom, There is really no introduction Jackson, Then we will introduce .
Spring The official already has one spring-boot-starter-json rely on , Let's lead in directly ：

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

Start again , Problem solving .

Review of problems

This dependency was not added to the previous project , It's normal , Why ？
After some investigation , The original project introduced spring-boot-starter-web rely on , It is pom The dependency has been introduced .