Question

我已经在这里待了几个小时，但还没有发现任何人已经开始工作了。我想在Mongo中保留一个BigDecimal对象，但是Mongo本身并不支持BigDecimal。我按照Spring的文档here但没有运气。

据我所知，Spring在写入数据库时没有将自定义转换器类注入Mongo。这就是我所做的：

我的applicationContext-services.xml ...

    <!-- Factory bean that creates the Mongo instance -->
    <mongo:mongo 
        host="localhost" 
        port="1234" />

    <mongo:db-factory 
        dbname="solar" 
        mongo-ref="mongo"/>

    <mongo:mapping-converter>
      <mongo:custom-converters>
        <mongo:converter>
          <bean class="com.mine.BigDecimalReadConverter"/>
        </mongo:converter>
        <mongo:converter>
          <bean class="com.mine..BigDecimalWriteConverter"/>
        </mongo:converter>
      </mongo:custom-converters>
    </mongo:mapping-converter>

    <!-- Use this post processor to translate any MongoExceptions thrown in @Repository annotated classes -->

    <bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

<bean id="mongoDbTest"
    class="com.mine.MongoDbTest">
    <property name="mongoTemplate">
        <ref local="mongoTemplate" />
    </property> 
</bean>

我得到的错误是：

java.lang.IllegalArgumentException: Multiple constructors with arguments found in class java.math.BigDecimal! Annotate one with @PreferedConstructor explicitly to select it to be used in persistence operations.
    at org.springframework.data.mapping.PreferredConstructorDiscoverer.<init>(PreferredConstructorDiscoverer.java:81)

Answer 1

尝试将此用于转换器支持：

<bean id="mappingContext"
    class="org.springframework.data.mongodb.core.mapping.MongoMappingContext" lazy-init="true"/>

 <bean id="defaultMongoTypeMapper"
    class="org.springframework.data.mongodb.core.convert.DefaultMongoTypeMapper" lazy-init="true">
    <constructor-arg name="typeKey"><null/></constructor-arg>
 </bean>

 <bean id="mappingMongoConverter"
    class="org.springframework.data.mongodb.core.convert.MappingMongoConverter" lazy-init="true" >
    <constructor-arg name="mongoDbFactory" ref="mongoDbFactory" />
    <constructor-arg name="mappingContext" ref="mappingContext" />
    <property name="typeMapper" ref="defaultMongoTypeMapper" />
 </bean>

 <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate" lazy-init="true">
    <constructor-arg name="mongoDbFactory" ref="mongoDbFactory" />
    <constructor-arg name="mongoConverter" ref="mappingMongoConverter" />
 </bean>

Answer 2

以下是我解决这个问题的方法。您定义bean的顺序很重要。所以我使用它的app.xml是：



 <bean id="mappingContext" class="org.springframework.data.document.mongodb.mapping.MongoMappingContext"/>

<bean id="readConverter"  class="com.mine.BigDecimalReadConverter"/>
<bean id="writeConverter"  class="com.mine.BigDecimalWriteConverter"/>

<mongo:mapping-converter id="mappingConverter">
    <mongo:custom-converters>
        <mongo:converter ref="readConverter" />
        <mongo:converter ref="writeConverter" />
    </mongo:custom-converters>
</mongo:mapping-converter>

<!-- Factory bean that creates the Mongo instance -->
<mongo:mongo 
    host="${${environment}.mongodb.host}" 
    port="${${environment}.mongodb.port}" />

<mongo:db-factory 
    dbname="${${environment}.mongodb.databaseName}" 
    mongo-ref="mongo"/>   

<bean id="mongoTemplate" class="org.springframework.data.document.mongodb.MongoTemplate">
    <constructor-arg name="mongoDbFactory" ref="mongoDbFactory" />
    <constructor-arg name="mongoConverter" ref="mappingConverter"/>
</bean>

<!-- Use this post processor to translate any MongoExceptions thrown in @Repository annotated classes -->
<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

如何在Spring中设置自定义Mongo格式化程序？

2 个答案: