MongoTemplate：匹配一定準則

Question

我下面MongoDB的查詢工作，甚至提到thesequestions & tutorial，其等效的Java代碼後，如預期

db.importedDataItems.aggregate({ 
    $match: { 
     mobile: "1234567890" 
    } 
}, { 
    $group: { 
     _id: 'mobile', 
     calls: { $sum: '$calls' } 
    } 
}) 

但文件鍵和值...

Aggregation agg = Aggregation.newAggregation(Aggregation.match(Criteria.where("mobile").is("1234567890"), 
    Aggregation.group("mobile").sum("calls").as("totalCalls"), 
    Aggregation.project("totalCalls")); 
AggregationResults<Doc> results = mongoTemplate.aggregate(agg, "yoCollection", 
    Doc.class); 
Doc doc = results.getMappedResults().get(0); 

...返回一個空列表&拋出IndexOutOfBoundsException雖然我的查詢返回控制檯上的結果！

Answer 1

你缺少一個右括號爲match()參數：

import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; 

Aggregation agg = Aggregation.newAggregation(
     match(Criteria.where("mobile").is("1234567890")), // <-- missing closing parenthesis 
     group("mobile").sum("calls").as("totalCalls") 
     project("totalCalls") 
    ); 

AggregationResults<Doc> results = mongoTemplate.aggregate(agg, "yoCollection", Doc.class); 
Doc doc = results.getMappedResults().get(0);