Java manipulation mongodb sample sharing

package mymaven;  

import java.net.UnknownHostException;  
import java.util.Set;  

import com.mongodb.BasicDBObject;  
import com.mongodb.DB;  
import com.mongodb.DBCollection;  
import com.mongodb.DBCursor;  
import com.mongodb.DBObject;  
import com.mongodb.Mongo;  
import com.mongodb.MongoException;  

public class Test {  
    public static void main(String[] args) throws UnknownHostException, MongoException {  
        Mongo mongo = new Mongo("172.27.9.104", 27017);     //Connect to database & NBSP;
        DB db = mongo.getDB("mytestdb");                    //Database  
        Set<String> cols = db.getCollectionNames();           //Gets all the collections in the database (similar to getting the tables in a relational database) & NBSP;

        //Print out the collection in the database, which should be null ;
        for (String s : cols) {  
            System.out.println(s);  
        }  

        DBCollection collection = db.getCollection("mytestcoll");       //Create a collection & NBSP;
        collection.drop();                                              //Deletes a collection, automatically rebuilds when data is inserted & NBSP;
        BasicDBObject obj = new BasicDBObject();                        //A basic DB object is initialized and the DB object & NBSP; is inserted into the database.

        obj.put("from", "blog.ithomer.net");        //Put in several key-value pairs & NBSP;
        obj.put("to", "forum.ithomer.net");  
        obj.put("subject", "ithomer.net");  
        collection.insert(obj);                     //Insert object & NBSP;

        DBObject dbobj = collection.findOne();      //View a record, findOne()=find().limit(1);  
        System.out.println(dbobj);                  //Print out the data you just inserted & NBSP;

        //Insert 10 {ranking: I} data & ranking;
        for (int i = 0; i < 10; i++) {  
            collection.insert(new BasicDBObject().append("ranking", i));  
        }  
        System.out.println("count: " + collection.getCount());      //The total number of data in the print collection & NBSP;

          
        DBCursor cursor = collection.find();        //Then we use this cursor to iterate over the collection & NBSP;
        while (cursor.hasNext()) {  
            System.out.println(cursor.next());  
        }  
        //Simple conditional query, the query ranking is 1 record & PI;
        BasicDBObject query = new BasicDBObject();  
        query.put("ranking", 1);  
        cursor = collection.find(query);  
        System.out.println("collection find({"ranking":1}):");  
        while (cursor.hasNext()) {  
            System.out.println(cursor.next());  
        }  

        //Complex conditional query, query ranking greater than or equal to 5 and less than 9
        query = new BasicDBObject();  
        query.put("ranking", new BasicDBObject("$gte", 5).append("$lt", 9));  
        cursor = collection.find(query);  
        System.out.println("collection find({"ranking":[5-9)}):");  
        while (cursor.hasNext()) {  
            System.out.println(cursor.next());  
        }  

//      mongo.dropDatabase("mytestdb");         //  Finally, delete our test database   
    }  
}  

Operation results:

mytestcoll
system.indexes
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10107"} , "from" : "blog.ithomer.net" , "to" : "forum.ithomer.net" , "subject" : "ithomer.net"}
count: 11
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10107"} , "from" : "blog.ithomer.net" , "to" : "forum.ithomer.net" , "subject" : "ithomer.net"}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10108"} , "ranking" : 0}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10109"} , "ranking" : 1}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010a"} , "ranking" : 2}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010b"} , "ranking" : 3}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010c"} , "ranking" : 4}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010d"} , "ranking" : 5}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010e"} , "ranking" : 6}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010f"} , "ranking" : 7}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10110"} , "ranking" : 8}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10111"} , "ranking" : 9}
collection find({"ranking":1}):
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10109"} , "ranking" : 1}
collection find({"ranking":[5-9)}):
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010d"} , "ranking" : 5}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010e"} , "ranking" : 6}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010f"} , "ranking" : 7}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10110"} , "ranking" : 8}

Example mongodb array:

 @SuppressWarnings("unchecked")
 public static void loadMediaTags(List<MediaEntity> mediaEntityList) {
  mediaEntityList.clear();

  try {
   Mongo mongo = new Mongo(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);
   DB db = mongo.getDB(CosineCluster.gMongo_DB);
   DBCollection collection = db.getCollection(CosineCluster.gMongo_Coll_Media);

   DBCursor cursor = collection.find();
   int index = 0;
   long startTime = System.currentTimeMillis();
   while(cursor.hasNext()){
    BasicDBObject obj = (BasicDBObject) cursor.next();

    long id = obj.getLong("_id");
    ArrayList<String> tagList = (ArrayList<String>) obj.get("tag");     // tag
    ArrayList<String> keywordList = (ArrayList<String>)obj.get("keyword");   // keyword
    ArrayList<Integer> copyrightList = (ArrayList<Integer>)obj.get("copyright"); // copyright

  
    MediaEntity mediaEntity = new MediaEntity();

    mediaEntity.setId(id);

    // tag
    for(int j=0; j<tagList.size(); j++) {
     mediaEntity.addTag(tagList.get(j));
     int tagId = getTagInt(tagList.get(j));
     mediaEntity.addTag(tagId);
    }

    // actors
    ArrayList<DBObject> actorsObjList = (ArrayList<DBObject>)obj.get("actors");  // actors
    for(int j=0; j<actorsObjList.size(); j++) {
      mediaEntity.addActor((String) actorsObjList.get(j).get("name")); 
      int actorId = getActorInt((String)actorsObjList.get(j).get("name"));
      mediaEntity.addActor(actorId);
    }
    // director
    ArrayList<DBObject> directorObjList = (ArrayList<DBObject>)obj.get("director"); // director
    for(int j=0; j<directorObjList.size(); j++) {
      mediaEntity.addDirector((String) directorObjList.get(j).get("name")); 
      int directorId = getDirectorInt((String) directorObjList.get(j).get("name"));
      mediaEntity.addDirector(directorId);
    }

    // keyword
    for(int j=0; j<keywordList.size(); j++) {
     mediaEntity.addKeyword(keywordList.get(j));
     int keywordId = getKeywordInt(keywordList.get(j));
     mediaEntity.addKeyword(keywordId);
    }

    // copyright
    for(int j=0; j<copyrightList.size(); j++) {
     mediaEntity.addCopyright(copyrightList.get(j));
    }

    mediaEntityList.add(mediaEntity);

    index++;
    if(index > 100) {
     break;
    }
    System.out.println(index + " --- mediaEntity : " + mediaEntity.toString());
   }
   long costTime = System.currentTimeMillis() - startTime;
   System.out.println("load data costTime = " + index + "; costTime = " + costTime/1000f);

  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 public static int getTagInt(String tag) {
  int tagIntId = -1;

  try {
   MongoClient mongo = new MongoClient(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);
   DB db = mongo.getDB(CosineCluster.gMongo_DB);
   DBCollection tagmapCollection = db.getCollection("recommend_tag_map");
   DBCursor cursor = tagmapCollection.find(new BasicDBObject("name", tag)); 
   if(cursor == null || cursor.toArray().size() <= 0) {  //Handles the mapping keyword less than 2 or n, the same as below
    return tagIntId;
   }
   DBObject obj = cursor.toArray().get(0);

   
   String name = tag;
   tagIntId = (Integer) obj.get("id");
   int num = (Integer) obj.get("num");

   mongo.close();
  } catch (UnknownHostException e) {
   e.printStackTrace();
  }

  return tagIntId;
 }
 public static int getActorInt(String actor) {
  int actorIntId = -1;
  try {
   MongoClient mongo = new MongoClient(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);
   DB db = mongo.getDB(CosineCluster.gMongo_DB);
   DBCollection tagmapCollection = db.getCollection("recommend_actor_map");

   DBCursor cursor = tagmapCollection.find(new BasicDBObject("name", actor));
   if(cursor == null || cursor.toArray().size() <= 0) {
    return actorIntId;
   }
   DBObject obj = cursor.toArray().get(0);

   String name = actor;
   actorIntId = (Integer) obj.get("id");
   int num = (Integer) obj.get("num");

   mongo.close();
  } catch (UnknownHostException e) {
   e.printStackTrace();
  }

  return actorIntId;
 }