使用spring data jdbc将Java Map持久化为PostgreSQL jsonb &g

Question

我正在使用spring-data-jdbc将以下实体持久化到PostgreSQL

@Table("abc_configurations")
data class AbcConfiguration(
val name: String,
val distribution: Map<String, Int>
)

分布是PostgreSQL表中的jsonb列:

CREATE TABLE abc_configurations
(
name          VARCHAR(50)    PRIMARY KEY,
distribution  JSONB    NOT NULL
);

我为此创建了以下自定义转换器:

import com.fasterxml.jackson.core.type.TypeReference
import com.fasterxml.jackson.databind.ObjectMapper
import org.postgresql.util.PGobject
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.core.convert.converter.Converter
import org.springframework.data.convert.ReadingConverter
import org.springframework.data.convert.WritingConverter
import org.springframework.data.jdbc.core.convert.JdbcCustomConversions
import org.springframework.data.jdbc.core.convert.JdbcValue
import org.springframework.data.jdbc.repository.config.AbstractJdbcConfiguration
import org.springframework.data.jdbc.repository.config.EnableJdbcRepositories
import java.sql.JDBCType
@Configuration
@EnableJdbcRepositories
class DataConfig : AbstractJdbcConfiguration() {
@Autowired
private lateinit var objectMapper: ObjectMapper;
@Bean
override fun jdbcCustomConversions(): JdbcCustomConversions {
val converters = listOf(
DistributionWritingConverter(objectMapper),
DistributionReadingConverter(objectMapper)
)
return JdbcCustomConversions(converters)
}
@WritingConverter
class DistributionWritingConverter(private val objectMapper: ObjectMapper) : Converter<Map<String, Int>, JdbcValue> {
override fun convert(source: Map<String, Int>): JdbcValue {
return JdbcValue.of(objectMapper.writeValueAsString(source), JDBCType.VARCHAR)
}
}
@ReadingConverter
class DistributionReadingConverter(private val objectMapper: ObjectMapper) : Converter<PGobject, Map<String, Int>> {
override fun convert(source: PGobject): Map<String, Int> {
return objectMapper.readValue(source.value, object : TypeReference<Map<String, Int>>() {})
}
}
}

当我持久化一个实体时，它工作得很好，并且分发Map按预期持久化到JSONB列中。

问题是当我读取实体时，我得到以下错误:Couldn't find PersistentEntity for type class java.lang.Integer!

org.springframework.data.mapping.MappingException: Couldn't find PersistentEntity for type class java.lang.Integer!
at org.springframework.data.mapping.context.MappingContext.getRequiredPersistentEntity(MappingContext.java:79) ~[spring-data-commons-2.4.5.jar:2.4.5]
at org.springframework.data.jdbc.core.convert.SqlGeneratorSource.lambda$getSqlGenerator$0(SqlGeneratorSource.java:62) ~[spring-data-jdbc-2.1.5.jar:2.1.5]
at java.base/java.util.concurrent.ConcurrentMap.computeIfAbsent(ConcurrentMap.java:330) ~[na:na]
at org.springframework.data.jdbc.core.convert.SqlGeneratorSource.getSqlGenerator(SqlGeneratorSource.java:61) ~[spring-data-jdbc-2.1.5.jar:2.1.5]
at org.springframework.data.jdbc.core.convert.DefaultDataAccessStrategy.sql(DefaultDataAccessStrategy.java:583) ~[spring-data-jdbc-2.1.5.jar:2.1.5]
at org.springframework.data.jdbc.core.convert.DefaultDataAccessStrategy.findAllByPath(DefaultDataAccessStrategy.java:362) ~[spring-data-jdbc-2.1.5.jar:2.1.5]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344) ~[spring-aop-5.3.4.jar:5.3.4]

我已经尝试将@ReadingConverter方法更改为以下不工作:

• Converter<String, Map<String, Int>>
• Converter<JdbcValue, Map<String, Int>>

ReadingConverter未被使用。

如何告诉spring使用自定义@ReadingConverter

更新(01.09.2021):

正如Jen和Susan提到的，这是spring-data-jdbc库的一个问题。我继续做下面的工作。

data class Distribution(val value: Map<String, Int>)

@Table("abc_configurations")
data class AbcConfiguration(
val name: String,
val distribution: Distribution
)

Answer 1

映射在Spring Data JDBC中得到了特殊处理，因此您不能简单地为它们使用转换器。相反，将映射包装在自定义类型中，并为该类型注册转换器。