Java操作MongoDB之mongodb-driver(一)

1. mongodb-driver是mongo官方推出的java連接mongoDB的驅動包，相當於JDBC驅動。

(1)通過maven倉庫導入:https://mvnrepository.com/artifact/org.mongodb/mongodb-driver

(2)官網中下載相應的java的驅動:http://docs.mongodb.org/ecosystem/drivers/java/

(3)不同的驅動使用的jar也不相同參考:http://mongodb.github.io/mongo-java-driver/

例如:

  <dependencies>
    <dependency>
        <groupId>org.mongodb</groupId>
        <artifactId>mongodb-driver-sync</artifactId>
        <version>3.11.2</version>
    </dependency>
  </dependencies>

 2. 創建方法類

2.1 查詢全部,遍歷打印

package mongodb.test;

import org.bson.Document;
import com.mongodb.BasicDBObject;
import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;

public class Mongodb {
    
    /**
     * 查詢打印全部集合
     */
    public static void mongoQueryAll() {
        //1.創建鏈接
        MongoClient client = new MongoClient("localhost");
        //2.打開數據庫test
        MongoDatabase db = client.getDatabase("test");
        //3.獲取集合
        MongoCollection<Document> collection = db.getCollection("stu");
        //4.查詢獲取文檔集合
        FindIterable<Document> documents = collection.find();
        //5.循環遍歷
        for (Document document : documents) {
            System.out.println(document);
        }
        //6.關閉連接
        client.close();
    }
    
    public static void main(String[] args) {
        mongoQueryAll();
    }

//打印輸出stu全部數據
Document{{_id=5d7374e836a89c5a3d18b87a, name=xiaohua}}
Document{{_id=2.0, sn=002, name=xiaogang}}
Document{{_id=3.0, sn=003, name=zhangfei, job=前鋒戰將}}
Document{{_id=5d73782736a89c5a3d18b87b, sn=004, name=xiaobingbing}}
Document{{_id=5d7396b44ec120618b2dd0cb, name=Document{{surname=李, name=世名}}, job=[皇帝, 大人物, 大丈夫, 功成名就]}}

2.2 條件查詢

    /**
     * 條件查詢：如查詢id為xxxx的學生所有信息
     */
    public static void mongoConditionQuery() {
        //1.創建鏈接
        MongoClient client = new MongoClient("localhost");
        //2.打開數據庫test
        MongoDatabase db = client.getDatabase("test");
        //3.獲取集合
        MongoCollection<Document> collection = db.getCollection("stu");
        //4.構建查詢條件，按照name來查詢
        BasicDBObject stu = new BasicDBObject("name","zhangfei");
        //5.通過id查詢記錄，獲取文檔集合
        FindIterable<Document> documents = collection.find(stu);
        //5.打印信息
        for (Document document : documents) {
            System.out.println("name:"+document.getString("name"));
            System.out.println("sn:"+document.getString("sn"));
            System.out.println("job:"+document.getString("job"));
        }
        //6.關閉連接
        client.close();
    }
    
    public static void main(String[] args) {
        mongoConditionQuery();
    }

//執行輸出
name:zhangfei
sn:003
job:前鋒戰將

注意:當需要查詢條件+判斷的時候這樣寫,例如查詢學號sn>003的學員

//查詢sum大於3的學員
BasicDBObject stu = new BasicDBObject("sum",new BasicDBObject("$gt",003));

2.3 插入語句

    /**
     * 插入語句
     */
    public static void mongoInsert() {
        //1.創建鏈接
        MongoClient client = new MongoClient("localhost");
        //2.打開數據庫test
        MongoDatabase db = client.getDatabase("test");
        //3.獲取集合
        MongoCollection<Document> collection = db.getCollection("stu");
        //4.准備插入數據
        HashMap<String, Object> map = new HashMap<String, Object>();
        map.put("sn","005");
        map.put("name","xiaoA");
        map.put("job","A工作");
        map.put("sum",6);
        //5.將map轉換成document
        Document document = new Document(map);
        collection.insertOne(document);
        //6.關閉連接
        client.close();
    }
    //測試執行
    public static void main(String[] args) {
        mongoInsert();
    }

批量插入,僅供參考:

//當需要插入多條文檔的時候，循環進行單條插入當然是可以，但是效率不高，MongoDB提供了批量插入的方法
List<DBObject> objs = new ArrayList<DBObject>();
objs.add(new BasicDBObject("name","user29").append("age", 30).append("sex", 1));
objs.add(new BasicDBObject("name","user30").append("age", 30).append("sex", 1));
collection.insert(objs);
//這樣就批量進行了插入。批量插入通過一次請求將數據傳遞給數據庫，然后由數據庫進行插入，比循環單條插入節省了每次進行請求的資源。

學習后總結,不足之處請指出,后續修改!