MongoDB的Java操作

// 需要三個jar包，mongodb-driver-3.3.0.jar；mongodb-drvier-core-3.3.0.jar；bson-3.3.0.jar
public class MongoTest {
    private MongoClient conn = null;

    // 獲取連接
    private MongoClient getConn() {
        conn = new MongoClient("127.0.0.1", 27017);
        return conn;
    }

    // 關閉連接
    private void close(MongoClient conn) {
        conn.close();
    }

    public void insert() {
        conn = this.getConn();
        // 獲取test數據庫，沒有自動創建
        MongoDatabase db = conn.getDatabase("test");
        // 獲取ss集合，沒有自動創建
        MongoCollection<Document> collection = db.getCollection("ss");

        // 創建文檔
        Document doc = new Document("name", "lt").append("sex", "男").append("age", 30);
        // 單量插入
        collection.insertOne(doc);
        // 批量插入
        List<Document> docList = new ArrayList<Document>();
        for (int i = 0; i < 20; i++) {
            docList.add(new Document(..).append(..).append(..));
        }
        collection.insertMany(docList);

        this.close(conn);
    }

    public int delete() {
        conn = this.getConn();
        MongoDatabase db = conn.getDatabase("test");
        MongoCollection<Document> collection = db.getCollection("ss");

        // 單量刪除
        collection.deleteOne(new Document("name", "new-lt10"));
        // 批量刪除
        DeleteResult deleteResult = collection.deleteMany(..);

        this.close(conn);
        // 返回影響文檔數
        return deleteResult.getDeletedCount();
    }

    public int update() {
        conn = this.getConn();
        MongoDatabase db = conn.getDatabase("test");
        MongoCollection<Document> collection = db.getCollection("ss");

        // 單量修改
        collection.updateOne(new Document("name", "lt10"), 
                new Document("$set", new Document("name", "new-lt10")));

        // 批量修改
        UpdateResult updateResult = collection.updateMany(new Document("name", "lt10"), 
                new Document("$set", new Document("name", "new-lt10")));

        this.close(conn);
        return updateResult.getModifiedCount()
    }

    public void list() {
        conn = this.getConn();
        MongoDatabase db = conn.getDatabase("test");
        MongoCollection<Document> collection = db.getCollection("ss");

        // 查詢集合大小
        collection.count();

        // 查詢集合的第一個文檔
        Document myDoc = collection.find().first();
        myDoc.toJson();

        // 查詢集合的全部文檔
        MongoCursor<Document> cursor = collection.find().iterator();
        while (cursor.hasNext()) {
            cursor.next().toJson();
        }

        // 查詢集合的全部文檔
        for (Document cur : collection.find()) {
            cur.toJson();
        }

        // 按條件查詢集合的指定文檔
        MongoCursor<Document> cursor = collection.find(
                            new Document("name", "lt")).iterator();
        while (cursor.hasNext()) {
            cursor.next().toJson();
        }

        // 使用QueryBuilder按條件查詢，找到name叫lt，且sex爲man的記錄
        QueryBuilder queryBuilder = 
            QueryBuilder.start("name").is("lt").and("set").is("man");


        this.close(conn);
    }
}