Spring数据MongoDB - $ eq内$项目支持 [英] Spring Data MongoDB - $eq within $project support
问题描述
我目前在我的Spring项目中编写一个聚合查询MongoDB，其中我使用$ project运算符。在这个操作符中，我想比较两个字段，以返回结果作为投影的匹配键值。这里是mongoDB shell等效（它的工作原理）：
{$ project：
{matches：
{$ eq：[$ lastDate $ meta.date]}
}
}
我阅读了Spring Data MongoDB文档，有用的信息关于ProjectionOperator的'andExpression'方法使用SpEL。我调查的结果Java代码是：
new ProjectionOperation（）。andExpression（lastDate == meta.date）。as（matches） 不幸的是我收到了异常：
java.lang.IllegalArgumentException：不支持的元素：
org.springframework.data.mongodb.core.spel.OperatorNode@70c1152a类型：class org.springframework.data.mongodb.core.spel.OperatorNode您的SpEL表达式中可能有语法错误！
就我已经检查，Spring Data MongoDB正确处理所有算术运算符，但不能处理比较。因此，我想问的是有什么其他方法来创建这样的查询与Spring Data MongoDB？
我通过传递JSON聚合命令（使用DBObjects创建）解决了这个问题为了保持查询的灵活性）到MongoDB，即：
MongoOperations＃executeCommand（DBObject command）
I'm currently writing an aggregation query for MongoDB in my Spring project in which I'm using $project operator. Within this operator I would like to compare two fields in order to return the result as projected "matches" key value. Here's the mongoDB shell equivalent (which works):
{$project:
{matches:
{$eq: ["$lastDate", "$meta.date"]}
}
}
I've read Spring Data MongoDB documentation and found some useful info about ProjectionOperator's 'andExpression' method which uses SpEL. The result Java code of my investigation was:
new ProjectionOperation().andExpression("lastDate == meta.date").as("matches")
Unfortunately I'm receiving exception:
java.lang.IllegalArgumentException: Unsupported Element:
org.springframework.data.mongodb.core.spel.OperatorNode@70c1152a Type: class org.springframework.data.mongodb.core.spel.OperatorNode You probably have a syntax error in your SpEL expression!
As far as I've checked, Spring Data MongoDB handles all Arithmetic operators correctly but cannot handle the comparison ones. Therefore I want to ask is there any other way to create such query with Spring Data MongoDB? Or maybe I don't know something crucial about SpEL?
I resolved this issue by passing JSON aggregate command (created with DBObjects in order to preserve flexibility of the query) to MongoDB, i.e.:
MongoOperations#executeCommand(DBObject command)
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