小编Mar*_*zas的帖子

我试图在一系列文档中总结一些值,没有运气.

这是文件

db.Cuentas.find().漂亮的()

{
    "Agno": "2013",
    "Egresos": [
        {
            "Fecha": "28-01-2013",
            "Monto": 150000,
            "Detalle": "Pago Nokia Lumia a @josellop"
        },
        {
            "Fecha": "29-01-2013",
            "Monto": 4000,
            "Detalle": "Cine, Pelicula fome"
        }
    ],
    "Ingresos": [],
    "Mes": "Enero",
    "Monto": 450000,
    "Usuario": "MarioCares"
    "_id": ObjectId(....)
}

因此,我需要"Eguos"中所有"Monto"的总和为"Usuario":"MarioCares".在这个例子154000

使用聚合我使用:

db.Cuentas.aggregate(
    [
        { $match: {"Usuario": "MarioCares"} },
        { $group: 
            {
                _id: null,
                "suma": { $sum: "$Egresos.Monto" }
            }
        }
    ]
)

但我总是得到

{ "result" : [{ "_id" : null, "suma" : 0 }], …

所以,我正在使用此代码从我的服务器创建报告PDF文件

response.setHeader("Expires", "0");
response.setHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");
response.setHeader("Pragma", "public");
response.setContentType("application/pdf");
List<Integer> cartas1 = new ArrayList<Integer>();
DeudorDAO DDAO = new DeudorDAO();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
    baos = DocumentoCartaCobranza.CrearDocumento(
        getServletContext().getRealPath("static/images/pdf_banner.jpg"),
        getServletContext().getRealPath("static/images/firmaJG.png"),
        getServletContext().getRealPath("static/images/firmaAB.jpg"),
        DDAO.getDatosFullDeudores(cartas1)
    );
} catch (DocumentException e) {
    e.printStackTrace();
}
OutputStream os = response.getOutputStream();
baos.writeTo(os);
os.flush();
os.close();

和

public static ByteArrayOutputStream CrearDocumento(
    String imgCabecera,
    String imgFirma,
    String imgAbogado,
    java.util.List<Deudor> carta1) throws DocumentException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            PdfWriter pdfw = null;
            pdfw = PdfWriter.getInstance( Documento, …