Java Operation MongoDB

Code Listing 1:

 PackageCom.ooooo.mongo;Importjava.net.UnknownHostException;ImportJava.util.Set;ImportOrg.json.JSONArray;Importorg.json.JSONException;ImportOrg.json.JSONObject;Importorg.junit.Test;ImportCom.mongodb.BasicDBObject;ImportCom.mongodb.DB;Importcom.mongodb.DBCollection;ImportCom.mongodb.DBCursor;Importcom.mongodb.MongoClient;Importcom.mongodb.MongoException; Public classJavamongodbtest {/*** Java + MongoDB Hello World example**/     Public Static voidMain (string[] args) {Try {           //instantiating a Mongo object, connecting 27017 portsMongoclient MONGO =NewMongoclient ("localhost", 27017); //connect a database named Yourdb, if the database does not exist, MongoDB will automatically establishDB db = Mongo.getdb ("Ytn-db"); //Get collection from MongoDB, database named "Yourdb"//A collection of data named Yourcolleection is obtained from MongoDB, and if the data collection does not exist, MongoDB creates a newDbcollection collection = Db.getcollection ("Yourcollection"); //use the Basicdbobject object to create a MongoDB document and give the assignment. Basicdbobject document =NewBasicdbobject (); Document.put ("id", 1002); Document.put ("MSG", "Hello World MongoDB in Java---ytan"); Document.put ("Msg23", "Hello World MongoDB in Java---yian--002"); Document.put ("msg23111", "Hello World MongoDB in Java---yun--002"); //Save the newly created document to the collectionCollection.insert (document); //create the document to queryBasicdbobject SearchQuery =NewBasicdbobject (); Searchquery.put ("id", 1002); //Find document Using Collection's Find methoddbcursor cursor =Collection.find (searchQuery); //Loop Output Results            while(Cursor.hasnext ()) {System.out.println (Cursor.next ()); } System.out.println ("Done"); } Catch(unknownhostexception e) {e.printstacktrace (); } Catch(mongoexception e) {e.printstacktrace (); }} @Test Public voidTestcase01_mongodb2json ()throwsException {//instantiating a Mongo object, connecting 27017 portsMongoclient MONGO =NewMongoclient ("localhost", 27017); //connect a database named Yourdb, if the database does not exist, MongoDB will automatically establish             for(String s:mongo.getdatabasenames ()) {System.out.println (s); } DB DB= Mongo.getdb ("Ynt-db"); Set<String> collections =Db.getcollectionnames ();  for(String collectionname:collections) {System.out.println (CollectionName); }                      //Get collection from MongoDB, database named "Yourdb"//A collection of data named Yourcolleection is obtained from MongoDB, and if the data collection does not exist, MongoDB creates a newDbcollection collection = Db.getcollection ("Yourcollection"); Basicdbobject SearchQuery=NewBasicdbobject (); Searchquery.put ("id", 1002); //Find document Using Collection's Find methoddbcursor cursor =Collection.find (searchQuery); Jsonobject Datajson=NewJsonobject (string.valueof (Cursor.next ()));   System.out.println (Datajson); //jsonobject response=datajson.getjsonobject ("msg");//Jsonarray Data=response.getjsonarray ("data");//Jsonobject info=data.getjsonobject (0);String province=datajson.getstring ("MSG"); String City=datajson.getstring ("id"); String District=datajson.getstring ("_id"); System.out.println (province+city+district); }}

MongoDB MONGO

using MONGODB requires importing the following classes, of course not all needed, and the classes used are imported. ImportCom.mongodb.Mongo; ImportCom.mongodb.DB; Importcom.mongodb.DBCollection; ImportCom.mongodb.BasicDBObject; ImportCom.mongodb.DBObject; ImportCom.mongodb.DBCursor; Importcom.mongodb.ObjectId;  Class conversion When a class object is stored in MongoDB, it is removed from MongoDB using Setobjectclass () to convert it back to its original class.  Public classTweetsImplementsDBObject {/* ... */} Tweet Mytweet=NewTweet (); Mytweet.put ("User", "Bruce"); Mytweet.put ("Message", "Fun"); Mytweet.put ("Date",NewDate ());  Collection.insert (Mytweet); //ConversionCollection.setobjectclass (Tweet); Tweet Mytweet=(Tweet) Collection.findone (); Default ID when the saved object has no set ID, MongoDB defaults to the record setting an ID ("_ID"). Of course you can also set your own specified ID, such as: (Executed in MongoDB with Db.users.save ({_id:1,name: ' Bruce '});) Basicdbobject Bo=NewBasicdbobject (); Bo.put (' _id ', 1); Bo.put (' Name ', ' Bruce ');  Collection.insert (BO);  Permission to determine if there is mongodb access, there is a return true, otherwise return false. BooleanAuth =db.authenticate (MyUserName, MyPassword); View MongoDB Database list Mongo m=NewMongo ();  for(String s:m.getdatabasenames ()) {System.out.println (s);  } View all the table names under the current library, equal to execute show tables in MongoDB; Set<String> Colls =Db.getcollectionnames ();  for(String s:colls) {System.out.println (s); View the index of a table list<DBObject> list =Coll.getindexinfo ();  for(DBObject o:list) {System.out.println (o); Delete a database Mongo m=NewMongo (); M.dropdatabase ("MyDatabaseName"); Create a MongoDB link Mongo m=NewMongo ("localhost", 27017); DB DB= M.getdb ("MyDatabaseName");//equivalent to the library nameDbcollection coll = db.getcollection ("myuserstable");//equivalent to table name#查询数据 Query The first record dbobject Firstdoc=Coll.findone ();  FindOne () returns a record, and find () returns the Dbcursor cursor object. Query all data dbcursor cur=Coll.find ();  while(Cur.hasnext ()) {System.out.println (Cur.next ());  The number of query Records Coll.find (). Count (); Coll.find (NewBasicdbobject ("Age", 26) . Count (); Set up a conditional query basicdbobject condition=NewBasicdbobject (); Condition.put ("Name", "Bruce"); Condition.put ("Age", 26);  Coll.find (condition); Querying part of the data block dbcursor cursor= Coll.find (). Skip (0). Limit (10);  while(Cursor.hasnext ()) {System.out.println (Cursor.next ()); } comparison query ( age> 50) basicdbobject Condition=NewBasicdbobject (); Condition.put ("Age",NewBasicdbobject ("$gt", 50));  Coll.find (condition); Comparison characters"$gt": Greater than"$gte": Greater than or equal to"$lt": Less than"$lte": Less than or equal to"$in": Contains//the following conditions query 20<age<=30Condition.put ("Age",NewBasicdbobject ("$gt"). Append ("$lte", 30)); #插入数据 BULK Insert List datas=NewArrayList ();  for(inti=0; I < 100; i++) {basicdbobject bo=NewBasicdbobject (); Bo.put ("Name", "Bruce"); Bo.append ("Age", i);  Datas.add (BO);  } coll.insert (Datas); Regular expression query all names match/joh?n/I's record pattern pattern= Pattern.compile ("Joh?n", case_insensitive); Basicdbobject Query=NewBasicdbobject ("name", pattern); Dbcursor cursor= Coll.find (query);

Java Operation MongoDB