MongoDB Aggregation Befehl Java-Code

Question

Dies ist mein mongodb Shell-Befehl:

db.dais_employee.aggregate([ 
    { 
     "$redact": { 
      "$cond": { 
       "if": { 
        "$gt": [ 
         { "$subtract": [ "$modifiedon", "$createdon" ] }, 
         1000 * 60 * 60 * 24 
        ] 
       }, 
       "then": "$$KEEP", 
       "else": "$$PRUNE" 
      } 
     } 
    } 
]) 

der gut arbeitet.

Ich brauche diesen MongoDB Befehl in Java zu arbeiten und ich brauche Hilfe für MongoDB Aggregation Framework mit Java-Treiber verwenden.

Wenn ich versuche, diesen Befehl mit Java-Treiber auszuführen:

AggregateIterable<Document> iterable = collection.aggregate(asList(
    new Document("$redact", 
     new Document("$cond", 
      new Document("if", 
       new Document("$gt", 
         asList(new Document("$subtract", 
          asList("$modifiedon", "$createdon") 
        ),1000 * 60 * 60 * 24) 
      ).append("then", "$$KEEP") 
       .append("else", "$$PRUNE") 
      ) 
     ) 
    ) 
)); 

, die eine Ausnahme auslöst,

Exception in thread "main" com.mongodb.MongoCommandException: Command failed with error 15990: 'exception: this object is already an operator expression, and can't be used as a document expression (at 'then')' on server 192.168.1.127:27017. The full response is { "errmsg" : "exception: this object is already an operator expression, and can't be used as a document expression (at 'then')", "code" : 15990, "ok" : 0.0 } 
    at com.mongodb.connection.ProtocolHelper.getCommandFailureException(ProtocolHelper.java:115) 
    at com.mongodb.connection.CommandProtocol.execute(CommandProtocol.java:114) 
    at com.mongodb.connection.DefaultServer$DefaultServerProtocolExecutor.execute(DefaultServer.java:159) 
    at com.mongodb.connection.DefaultServerConnection.executeProtocol(DefaultServerConnection.java:286) 
    at com.mongodb.connection.DefaultServerConnection.command(DefaultServerConnection.java:173) 
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:215) 
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:206) 
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:112) 
    at com.mongodb.operation.AggregateOperation$1.call(AggregateOperation.java:227) 
    at com.mongodb.operation.AggregateOperation$1.call(AggregateOperation.java:223) 
    at com.mongodb.operation.OperationHelper.withConnectionSource(OperationHelper.java:239) 
    at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:212) 
    at com.mongodb.operation.AggregateOperation.execute(AggregateOperation.java:223) 
    at com.mongodb.operation.AggregateOperation.execute(AggregateOperation.java:65) 
    at com.mongodb.Mongo.execute(Mongo.java:772) 
    at com.mongodb.Mongo$2.execute(Mongo.java:759) 
    at com.mongodb.OperationIterable.iterator(OperationIterable.java:47) 
    at com.mongodb.OperationIterable.forEach(OperationIterable.java:70) 
    at com.mongodb.AggregateIterableImpl.forEach(AggregateIterableImpl.java:117) 
    at threadpack.queryBtDates.main(queryBtDates.java:88) 

Helfen Sie mir, den Fehler zu erfahren, oder richtigen Code zu geben, dies zu laufen Befehl mit Java-Treiber.

Answer 1

asList("$modifiedon",1000) sollte asList("$modifiedon","$createdon") gemäß der Arbeits Pipeline von Ihnen zur Verfügung stehen.

Wie Sie die Bearbeitung getan haben. Kann sehen, dass das Problem ist, dass Sie das "then" und "else" an das "$ gt" -Dokument und nicht "wenn" anhängen.

Also statt:

AggregateIterable<Document> iterable = collection.aggregate(

asList(new Document("$redact", 
     new Document("$cond", 
      new Document("if", 
       new Document("$gt", 
         asList(new Document("$subtract", 
          asList("$modifiedon", "$createdon") 
        ),1000 * 60 * 60 * 24) 
      ).append("then", "$$KEEP") 
       .append("else", "$$PRUNE") 
      ) 
     ) 
    ) 
)); 

Sie tun sollten:

AggregateIterable<Document> iterable = collection.aggregate(

asList(new Document("$redact", 
     new Document("$cond", 
      new Document("if", 
       new Document("$gt", 
         asList(new Document("$subtract", 
          asList("$modifiedon", "$createdon") 
        ),1000 * 60 * 60 * 24) 
      ) 
      ).append("then", "$$KEEP") 
       .append("else", "$$PRUNE") 
     ) 
    ) 
));