Java operations on MongoDB instances

I finally ran my first Java MongoDB operation example. I don't know why MongoDB will always be locked every time I start the machine. I need to delete the lock file to start it, is it related to your own Windows 7 system? Puzzling!

1. PackageMongodb;
3. ImportJava.net. UnknownHostException;
4. ImportCom. mongodb. BasicDBObject;
5. ImportCom. mongodb. DB;
6. ImportCom. mongodb. DBCollection;
7. ImportCom. mongodb. DBCursor;
8. ImportCom. mongodb. Mongo;
9. ImportCom. mongodb. MongoException;
11. /** 
12. * Java + MongoDB Hello world Example 
13. * 
14. */
15. Public ClassMongoDb {
16. Public Static VoidMain (String [] args ){
17. Try{
18. // Instantiate a Mongo object and connect to port 27017
19. Mongo mongo =NewMongo ("Localhost",27017);
20. // Connect to the database named xiaodb. If the database does not exist, mongodb will automatically create
21. DB db = mongo. getDB ("Xiaodb");
22. // Get collection from MongoDB, database named "xiao"
23. // Obtain the data set named users from Mongodb. If the data set does not exist, Mongodb creates a new
24. DBCollection collection = db. getCollection ("Users");
25. // Use the BasicDBObject object to create a document for mongodb and assign a value to it.
26. BasicDBObject document =NewBasicDBObject ();
27. Document. put ("Id",1001);
28. Document. put ("Msg","Hello world mongoDB in Java");
29. // Save the newly created document to the collection.
30. Collection. insert (document );
31. // Create the document to query
32. BasicDBObject searchQuery =NewBasicDBObject ();
33. SearchQuery. put ("Id",1002);
34. // Use the find method of collection to find the document
35. DBCursor cursor = collection. find (searchQuery );
36. // Cyclically output results
37. While(Cursor. hasNext ()){
38. System. out. println (cursor. next ());
39. }
40. System. out. println ("Done");
41. }Catch(UnknownHostException e ){
42. E. printStackTrace ();
43. }Catch(Except exception e ){
44. E. printStackTrace ();
45. }
46. }
47. }