使用jmeter中的groovy在MongoDB中查找聚合

我在MongoDB有两个收藏。我使用jmeter中的jsr223采样器在MongoDB上执行查找操作。
数据库名称: 数据库
集合名称: CY1,CY2

在MongoDB中执行查找聚合的groovy代码。

c_1.insert(new BasicDBObject(["id" : 1, "name" : "abc", "lastName" : "kumar",  "companyId": 10]))  

c_2.insert(new BasicDBObject(["id" : 10, "companyName" : "Microsoft", "numEmployee" : 100 ]))  

// build the $lookup operations  
DBObject lookupFields = new BasicDBObject("from", "c_2");  
lookupFields.put("localField", "companyId");  
lookupFields.put("foreignField", "id");  
lookupFields.put("as", "companydoc");   
DBObject lookup = new BasicDBObject("$lookup", lookupFields);  

// build the $project operations  
DBObject projectFields = new BasicDBObject("name", 1);  
projectFields.put("lastName", 1);  
projectFields.put("companyId", 1);  
projectFields.put("companyName", "$c_2.companyName");         
DBObject project = new BasicDBObject("$project", projectFields);  
List<DBObject> pipeline = Arrays.asList(lookup, project);  
AggregationOutput output = c_1.aggregate(pipeline);  
for (DBObject result : output.results())    
{  
    System.out.println(result);  
}   

错误: 响应消息:javax.script.scriptException:groovy.lang.MissingPropertyException:no such属性:查找类:script79