MongoDB 学习笔记三 JAVA调用MongoDB

驱动

​​https://github.com/mongodb/mongo-java-driver​​​
​​​http://central.maven.org/maven2/org/mongodb/mongo-java-driver/​​

连接

private static void mongo_conn(){
    MongoClient mongoClient = new MongoClient(properties.getProperty("mongo_host") , 27017 );
    mongoDB = mongoClient.getDatabase(properties.getProperty("mongo_db"));
}

查找

MongoCollection<Document>  users = mongoDB.getCollection("coll");
Document findObj=users.find(new Document("SEGMENT1","abc")).first();
if(findObj!=null){
    return findObj.get("name").toString();
}

插入

MongoCollection<Document>  coll= mongoDB.getCollection("coll_name");
coll.insertOne(new Document("name","abc")
        .append("age",20)
        );

查找更新

注意要引用：
import static com.mongodb.client.model.Filters.*;

coll.updateOne(eq("id",3), new Document("$set",new Document("HANDLED",true)));

coll.findOneAndReplace(doc1, doc2);

JSON 转换

DBObject dbObject = (DBObject) JSON.parse("{'name':'mkyong', 'age':30}");
String str=JSON.serialize(dbObject);

MapReduce

String map="function(){"+
            "emit(this.MATERIAL_CODE,{count:1,RECORD_DATE:this.RECORD_DATE} );"+
        "}";
        String reduce="function(key,values){"+
            "var earliest_record_date=new Date('2099-1-1');"+
            "var sum=0;"+
            "for(var i=0;i<values.length;i++){"+
            "   var m=values[i];"+
            "   sum += m.count;"+
            "   if(m.record_date){"+
            "       if(m.record_date<earliest_record_date)"+
            "           earliest_record_date=m.record_date;"+
            "   };"+
            "}"+
            "return {count:sum,RECORD_DATE:earliest_record_date};"+
        "}";
        MapReduceIterable<Document>  result= CRM_CSS_REPAIR_ORDER_TABLE_coll.mapReduce(map, reduce)
        .filter(
                and(
                        //eq("cateogry_id",category_id)
                        //,gt("PRODUCE_DATE",tempYearMonth)
                        //,lt("PRODUCE_DATE",dateLastDay)
                        )
                )
        .action(MapReduceAction.REPLACE);
         MongoCursor<Document> cursor = result.iterator();
         int i=0;
         String sql="";
         while (cursor.hasNext()) {
             i++;
             Document d=cursor.next();
             Document _id = (Document)d.get("_id");          
             Document value=(Document)d.get("value");
             Date record_date=value.getDate("RECORD_DATE");
             Date purchase_date=value.getDate("PURCHASE_DATE");
             double count=value.getDouble("count");
        }

aggregate

db.CRM_CSS_REPAIR_ORDER_TABLE.aggregate(
   [
        {
            $group : {
                _id : { 
                    key1:"$COLUMN_NAME"
                    "key2_date_year":{$year:"$produce_date"},
                    "key3_date_month":{$month:"$produce_date"}
                },
                count: { $sum: 1 },
                min_RECORD_DATE:{$min:'$RECORD_DATE'},
                min_purchase_date:{$min:'$purchase_date'}
            }

        },
        {
            $sort:{
                count:-1
            }
        }
   ]
)

java代码

List<Document> pipeline = Arrays.asList(
    new Document("$group", new Document( "_id", 
            new Document("MATERIAL_CODE","$MATERIAL_CODE")                         
                .append("PROVINCE_NAME","$PROVINCE_NAME")
                .append("RECORD_DATE_YEAR",new Document("$year","$RECORD_DATE"))
                .append("RECORD_DATE_MONTH",new Document("$month","$RECORD_DATE"))
            )
            .append("count", new Document("$sum",1))
            .append("min_produce_date",new Document("$min","$produce_date"))
    )
    ), 
    new Document("$sort", new Document("count", -1))
);    

AggregateIterable<Document> iterable = CRM_CSS_REPAIR_ORDER_TABLE_coll.aggregate(pipeline).allowDiskUse(true);
int i=0;
for (Document d : iterable){
     i++;
     Document _id=(Document)d.get("_id");
     String ITEM_NUMBER=_id.getString("MATERIAL_CODE");
}

参考：
​​​http://mongodb.github.io/mongo-java-driver/3.0/driver/getting-started/quick-tour/​​