Java MongoDB Save/Read application examples

The following example inserts a user object into the MongoDB and reads it

The code is as follows

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user.java: Package Com.mongo;   public class User {  string name;  int age;  oid _id;  public String G Etname () {   return name;  }  public void SetName (String name) {    THIS.name = name;  }  public int getage () {   return age;  .}  public void setage (int age) {   ;  this.age = age;  }  /**   * MongoDB automatically generates Objectid   * @author FHP   *   */  public Clas s oid{   string $oid;   public String get$oid () {    return $oid; & NBSP;&NBSP}     public void set$oid (String $oid) {    this. $oid = $oid; & NBSP;&NBSP}    } }

Main.java:

The code is as follows

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Package Com.mongo; Import java.net.UnknownHostException; Import Com.google.gson.Gson; Import Com.mongodb.DB; Import com.mongodb.DBCollection; Import Com.mongodb.DBCursor; Import Com.mongodb.DBObject; Import com.mongodb.MongoClient; Import Com.mongodb.util.JSON; public class Main { /** * @param args * @throws unknownhostexception */ public static void Main (string[] args) throws Unknownhostexception { TODO auto-generated Method Stub Mongoclient mongoclient = new Mongoclient (); DB Psdoc = Mongoclient.getdb ("Psdoc"); Dbcollection user=psdoc.getcollection ("user"); User U1=new user (); U1.setage (20); U1.setname ("SSSs"); Gson gson=new Gson (); Convert to JSON string, then convert to DBObject object DBObject dbobject = (dbobject) json.parse (Gson.tojson (U1)); Insert Database User.insert (DBObject); Dbcursor Cursor=user.find (); while (Cursor.hasnext ()) { DBObject Obj=cursor.next (); Reverse User U=gson.fromjson (obj.tostring (), user.class); System.out.println (u.name); } } }

In order to facilitate, you can directly integrate the Gson into the drive, directly modify the driving source code
Com.mongodb.DBCollection.java:
New methods:

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/** * Write common objects to the database * * @param obj * @return */ Public writeresult Insert (Object obj) { Gson Gson = new Gson (); DBObject dbobject = (dbobject) json.parse (Gson.tojson (obj)); Gson=null; return insert (DBObject); } Com.mongodb.DBCursor.java:

New methods

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/** * Read the object from the database * @param obj * @param clazz * @return */ Public <T> T nextobj (class<t> clazz) { _checktype (Cursortype.iterator); Gson gson=new Gson (); T U=gson.fromjson (_next (). toString (), clazz); Gson=null; return u; }

Modified method of invocation:

The code is as follows

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Main.java: Package Com.mongo; Import java.net.UnknownHostException; Import Com.mongodb.DB; Import com.mongodb.DBCollection; Import Com.mongodb.DBCursor; Import com.mongodb.MongoClient; public class Main { /** * @param args * @throws unknownhostexception */ public static void Main (string[] args) throws Unknownhostexception { TODO auto-generated Method Stub Mongoclient mongoclient = new Mongoclient (); DB Psdoc = Mongoclient.getdb ("Psdoc"); Dbcollection user=psdoc.getcollection ("user"); User U1=new user (); U1.setage (20); U1.setname ("SSSs"); Insert Object directly User.insert (U1); Dbcursor Cursor=user.find (); while (Cursor.hasnext ()) { Pass in the class parameter, back to the class object User u=cursor.nextobj (User.class); System.out.println (u.name); } } }