MongoDB using Java part 1 - update

package mongodb;

import java.util.ArrayList;
import java.util.List;
import java.net.UnknownHostException;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.MongoCredential;
import com.mongodb.MongoClient;
import com.mongodb.ServerAddress;

public class MongdbUpdate {

 public static void main(String[] args) {
  // TODO Auto-generated method stub
  try
  {
   // 認證
   MongoCredential journaldevAuth = MongoCredential.createMongoCRCredential("username", "database", "password".toCharArray());
   List auths = new ArrayList();
   auths.add(journaldevAuth);

   //連線
   ServerAddress serverAddress = new ServerAddress("your server address", your port);
   MongoClient mongo = new MongoClient(serverAddress,auths);

   //選擇連線database
   DB db = mongo.getDB("database");

   //選擇collection (table)
   DBCollection site = db.getCollection("site");
   
   // $set
   BasicDBObject query = new BasicDBObject();
   query.put("city", "taipei");
   BasicDBObject newDocument = new BasicDBObject();
   newDocument.put("num", 125);
   
   BasicDBObject updateObj = new BasicDBObject();
   updateObj.put("$set", newDocument);
   
   site.update(query, updateObj, true, true);
   
   // $inc
   updateObj.clear();
   updateObj.put("$inc", newDocument);
   site.update(query, updateObj, true, true);
  }
  catch(UnknownHostException ex)
  {

  }
 }

}