Java MongoTemplate聚合是否为所有字段生成空值？

我正在与MongoDD合作开发Spring，目标是从查询中获得结果并将其绘制到google地图中。在这里，我进行了聚合以获取字段的计数并与之匹配，但在迭代AggregationResults时，我得到了空值

这是我的密码：

GroupOperation groupByState =Aggregation. group("State_1").sum("NPI").as("doctor_count");
MatchOperation filterStates = Aggregation.match(new Criteria("doctor_count").lt(10000000));
SortOperation sortByCntDesc = Aggregation.sort(new Sort(Direction.DESC, "doctor_count"));
Aggregation aggregation =Aggregation.newAggregation( groupByState, filterStates, sortByCntDesc);
AggregationResults<FilterFieldsModelBean> result = mongoTemplate.aggregate(aggregation, "doctor_details", FilterFieldsModelBean.class);
list = result.getMappedResults();
System.out.println("list: "+list.size());

for(FilterFieldsModelBean bean:list){
    System.out.println(">> "+bean.getDoctor_count());
    System.out.println(">> "+bean.getCity());
    System.out.println(">> "+bean.getState());
    System.out.println(">> "+bean.getNPI());
    System.out.println(">> "+bean.getFirst_Name());
}

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纠正我的错误。感谢您的帮助：）

您是否可以添加希望查询代码返回的示例文档？您是否可以添加希望查询代码返回的示例文档？

@Id
private String id;

private String NPI;
private String PAC_ID;
private String Professional_Enrollment_ID;

@Field("Last_Name")
private String Last_Name;

@Field("First_Name")
private String First_Name;

@Field("Middle_Name")
private String Middle_Name;

@Field("Gender_1")
private String Gender;

@Field("Medical_school_name")
private String Medical_school_name;

@Field("Primary_specialty")
private String Primary;

@Field("City_1")
private String City;

@Field("State_1")
private String States;

@Field("Graduation_year")
private String Graduation_year;

private String Zip_Code;
private String Phone_Number;
private String Organization_legal_name;
private String Group_Practice_PAC_ID;


@Field("latitude")
private String latitude;
@Field("longitude")
private String longitude;

private String Doctor_count;