春季数据mongodb _id映射首选项 [英] spring data mongodb _id mapping preference

问题描述

我在Java应用程序中使用spring data mongodb框架将应用程序数据持久存储在mongodb中.在我的Java模型类中，我有两个字段.

I am using spring data mongodb framework in my java application to persist my application data in mongodb. In my java model class I have two fields.

1)带有@Id注释的objId字段. 2)字段ID

1) A field objId with @Id annotation on it. 2) A field id

，哪个将获得首选项，或者我将为多次映射而出错.我正在使用spring data mongo 1.6.1.我知道我可以对此进行测试，但是我没有本地环境设置.

with respect to mapping to _id key in the mongodb document saved, which one will get preference or will I get an error for multiple mapping. I am using spring data mongo 1.6.1. I know I could have tested this out but I do not have local environment setup.

推荐答案

答案在文档 http://docs.spring.io/spring-data/data-mongo/docs/1.7.0.M1/reference/html/

The answer is in documentation http://docs.spring.io/spring-data/data-mongo/docs/1.7.0.M1/reference/html/

MongoDB要求所有文档都有一个"_id"字段.如果 您不提供驱动程序，驱动程序将为ObjectId分配一个 产生的价值.使用MongoMappingConverter时 某些规则，这些规则控制Java类的属性如何映射 到此"_id"字段.

MongoDB requires that you have an '_id' field for all documents. If you don’t provide one the driver will assign a ObjectId with a generated value. When using the MongoMappingConverter there are certain rules that govern how properties from the Java class is mapped to this '_id' field.

以下概述了将什么属性映射到'_id' 文档字段:

The following outlines what property will be mapped to the '_id' document field:

用@Id注释的属性或字段 (org.springframework.data.annotation.Id)将映射到'_id' 字段.

A property or field annotated with @Id (org.springframework.data.annotation.Id) will be mapped to the '_id' field.

没有注释但命名为id的属性或字段将被映射 到"_id"字段.

A property or field without an annotation but named id will be mapped to the '_id' field.

如您所见，@ Id(objId)将优先.

As you can see @Id (objId) will take precedence.

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