通过Java连接MongoDB服务器，需要使用mongodb的jar

import java.net.UnknownHostException; import java.util.Set;
import com.mongodb.DB;
import com.mongodb.DBCollection; import com.mongodb.DBCursor;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

public class ConnectToMongoDB { 
    Mongo m = null;
    DB db;

    public void connect() { 
        try {
            m = new Mongo(“localhost”, 27017 ); 
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (MongoException e) { 
            e.printStackTrace();
        }
    }

    public void listAllCollections(String dbName) { 
        if(m!=null){
            db = m.getDB(dbName);
            Set<String> collections = db.getCollectionNames();
            for (String s : collections) { 
                System.out.println(s);
            } 
        }
    }


    public void listLocationCollectionDocuments() { 
        if(m!=null){
            db = m.getDB(“prefs”);
            DBCollection collection = db.getCollection(“location”);
            DBCursor cur = collection.find();
            while(cur.hasNext()) { 
                System.out.println(cur.next());
            }
        } else {
            System.out.println(“Please connect to MongoDB and then fetch the collection”);
        } 
    }

    public static void main(String[] args) {
        ConnectToMongoDB connectToMongoDB = new ConnectToMongoDB(); 
        connectToMongoDB.connect(); 
        connectToMongoDB.listAllCollections(“prefs”); 
        connectToMongoDB.listLocationCollectionDocuments();
    } 
}