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在使用SpringBoot中使用MongoTemplate时,数据库中数据会有_class字段.。_class的意义,在下面这个链接有很好的解答:
http://stackoverflow.com/questions/6810488/spring-data-mongodb-mappingmongoconverter-remove-class/
,其实就是说,为了在把document转换成Java对象时能够转换到具体的子类.。
要去掉的方法简单:DefaultMongoTypeMapper类的构造函数的第一个参数是Type在MongoDB中名字. 设置为null的话就不会在保存时自动添加_class属性.所以需要覆写
以下就是去除_class 字段的配置类,只需将代码复制即可直接使用。
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.convert.CustomConversions;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.core.convert.DbRefResolver;
import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
import org.springframework.data.mongodb.core.convert.DefaultMongoTypeMapper;
import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
/**
* Create by JIUN·LIU at 2018/7/24
*/
@Configuration
public class MongoConfig {
@Bean
public MappingMongoConverter mappingMongoConverter(MongoDbFactory factory, MongoMappingContext context, BeanFactory beanFactory) {
DbRefResolver dbRefResolver = new DefaultDbRefResolver(factory);
MappingMongoConverter mappingConverter = new MappingMongoConverter(dbRefResolver, context);
try {
mappingConverter.setCustomConversions(beanFactory.getBean(CustomConversions.class));
} catch (NoSuchBeanDefinitionException ignore) {
}
// Don't save _class to mongo
mappingConverter.setTypeMapper(new DefaultMongoTypeMapper(null));
return mappingConverter;
}
}
如果不是spring boot项目则可以用xml配置。
<mongo:mongo host="localhost" port="27017" />
<mongo:db-factory dbname="database" />
<bean id="mappingContext"
class="org.springframework.data.mongodb.core.mapping.MongoMappingContext" />
<bean id="defaultMongoTypeMapper"
class="org.springframework.data.mongodb.core.convert.DefaultMongoTypeMapper">
<constructor-arg name="typeKey"><null/></constructor-arg>
</bean>
<bean id="mappingMongoConverter"
class="org.springframework.data.mongodb.core.convert.MappingMongoConverter">
<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">
<constructor-arg name="mongoDbFactory" ref="mongoDbFactory" />
<constructor-arg name="mongoConverter" ref="mappingMongoConverter" />
</bean>