mongodb

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.bson.BsonDocument;
import org.bson.Document;
import org.bson.codecs.configuration.CodecRegistry;
import org.bson.conversions.Bson;

import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.MongoIterable;

public class MongdbTest
{
    public static void main(String[] args)
    {
        final MongoClient client = new MongoClient("localhost", 27017); // 这个方法共有16个重载的，可根据自己情况使用不同的方法
        final MongoDatabase mytest = client.getDatabase("mytest");
        System.out.println("已经连接到了数据库");

        // 新建并查询集合
        final MongoCollection<Document> collection_hello = mytest.getCollection("hello");
        if (null == collection_hello)
        {
            createCollection(mytest, "hello");
        }
        final List<String> collectionNames = showCollections(mytest);
        System.out.println(collectionNames);

        // 往集合里填数据：
        final List<Document> data = getData();
        insert(mytest, "hello", data);

        // 查询数据
        List<Document> docList = find(mytest, "hello");
        for (final Document doc : docList)
        {
            System.out.println(doc);
        }

        // 查询一个有过滤条件的
        docList = findWithCondition(mytest, "hello", new Bson()
        {
            public <TDocument> BsonDocument toBsonDocument(Class<TDocument> documentClass, CodecRegistry codecRegistry)
            {
                // TODO
                return null;
            }
        });
        for (final Document doc : docList)
        {
            System.out.println(doc);
        }
        client.close();
    }

    /**
     * 创建一个collection
     * 
     * @param db
     *            数据库对象
     * @param collectionName
     *            集合名称
     */
    public static void createCollection(MongoDatabase db, String collectionName)
    {
        db.createCollection(collectionName);
    }

    /**
     * 等同于命令行中的show collections
     * 
     * @param db
     * @return 当前库中的集合
     */
    public static List<String> showCollections(MongoDatabase db)
    {
        final ArrayList<String> collectionNameArray = new ArrayList<String>();
        final MongoIterable<String> collectionNames = db.listCollectionNames();
        final MongoCursor<String> iter = collectionNames.iterator();
        while (iter.hasNext())
        {
            collectionNameArray.add(iter.next());
        }
        return collectionNameArray;
    }

    /**
     * 插入数据
     * 
     * @param db
     * @param collectionName
     *            集合名
     * @param docList
     *            文档列表
     */
    public static void insert(MongoDatabase db, String collectionName, List<Document> docList)
    {
        final MongoCollection<Document> collection = db.getCollection(collectionName);
        collection.insertMany(docList);
    }

    /**
     * 模拟得到业务数据
     * 
     * @return
     */
    public static List<Document> getData()
    {
        final List<Document> docList = new ArrayList<Document>();
        // 拼接组装第一条document
        final Map<String, Object> doc = new HashMap<String, Object>();
        doc.put("name", "dwh");
        doc.put("age", 20);
        final HashMap<String, String> addressMap = new HashMap<String, String>();
        addressMap.put("country", "china");
        addressMap.put("province", "shanxi");
        addressMap.put("city", "平遥");
        doc.put("address", addressMap);
        final ArrayList<String> hobbyList = new ArrayList<String>();
        hobbyList.add("篮球");
        hobbyList.add("排球");
        hobbyList.add("hello");
        doc.put("hobby", hobbyList);

        docList.add(new Document(doc)); // 添加到list中去

        // 拼接组装第二条document
        doc.clear();
        doc.put("name", "dwh2017");
        doc.put("age", 25);
        addressMap.clear();
        addressMap.put("country", "china");
        addressMap.put("province", "北京");
        addressMap.put("city", "海淀");
        doc.put("address", addressMap);
        hobbyList.clear();
        hobbyList.add("羽毛球");
        hobbyList.add("排球");
        hobbyList.add("world");
        doc.put("hobby", hobbyList);

        docList.add(new Document(doc)); // 添加list中去

        return docList;
    }

    /**
     * 查询数据
     * 
     * @param db
     * @param collectionName
     * @return
     */
    public static List<Document> find(MongoDatabase db, String collectionName)
    {
        final List<Document> docList = new ArrayList<Document>();
        final MongoCollection<Document> collection = db.getCollection(collectionName);
        final FindIterable<Document> find = collection.find();
        final MongoCursor<Document> cursor = find.iterator();
        while (cursor.hasNext())
        {
            docList.add(cursor.next());
        }
        return docList;
    }

    /**
     * 有条件滴查询数据
     * 
     * @param db
     * @param collectionName
     * @param bson
     *            条件
     * @return
     */
    public static List<Document> findWithCondition(MongoDatabase db, String collectionName, Bson bson)
    {
        final List<Document> docList = new ArrayList<Document>();
        final MongoCollection<Document> collection = db.getCollection(collectionName);
        final FindIterable<Document> find = collection.find(bson);
        final MongoCursor<Document> cursor = find.iterator();
        while (cursor.hasNext())
        {
            docList.add(cursor.next());
        }
        return docList;
    }
}