Mongo/Java Map-Reduce 函数 - MongoCommandException

Question

I get the following error: com.mongodb.MongoCommandException: Command failed with error 139: 'SyntaxError: missing ; before statement @:1:60 ' on server localhost:27017. The full response is { "ok" : 0.0, "errmsg" : "SyntaxError: missing ; before statement @:1:60\\n", "code" : 139

It seems I am missing a ; but cannot seem to see where. The method is self-explanatory, I tend to create an map/reduce via mongo. Any help is appreciated.

public void mapFunction()
           {
               Mongo mongo = null;
               try{
               mongo = new Mongo("localhost", 27017);
               DB db = mongo.getDB("amarokforumdb");

               DBCollection comments = db.getCollection("comments");  
               String map = "function() { "+
                     "var category; " + 
                         "var numOfDocuments = "+db+".comments.count();" +

                         "for(i = 0; i < numOfDocuments; i++){ " +
                     "if (numOfDocuments <= 100) {"+ 
                     "category = 'New Comments'; }" +
                     "else if(numOfDocuments > 100){" +
                     "category = 'Old Comments'; }}"+ 
                     "emit(category,1);};";

               String reduce = "function(key, values) { " +
                                    "var sum = 0; " +
                                    "values.forEach(function(doc) { " +
                                    "sum += 1; "+
                                    "}); " +
                                    "return {comments: sum};} ";


                MapReduceCommand cmd = new MapReduceCommand(comments, map, reduce,
            null, MapReduceCommand.OutputType.INLINE, null);

            MapReduceOutput out = comments.mapReduce(cmd);



               for (DBObject o : out.results()) {
            System.out.println(o.toString());
               }}catch (Exception e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
          }

           }

Answer 1

Replace the "+db+".comments.count(); with an integer for testing, I think you got something wrong with that +db+ part