3. mongodb Java编写代码操作
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0. 默认使用Maven
<!-- https://mvnrepository.com/artifact/org.mongodb/mongodb-driver -->
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongodb-driver</artifactId>
<version>3.10.2</version>
</dependency>
1. 代码
package com.chenwen;
import com.mongodb.BasicDBObject;
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.model.InsertOneModel;
import com.mongodb.client.model.UpdateManyModel;
import com.mongodb.client.model.WriteModel;
import org.bson.BasicBSONObject;
import org.bson.Document;
import org.junit.Before;
import org.junit.Test;
import java.util.*;
/**
* TestMongodb
*
* @author chenwen
* @desc
* @Date 2019/7/29 11:25
*/
public class TestMongodb
private MongoCollection<Document> mongoCollection;
private Random random = new Random();
@Before
public void init()
MongoClient mongoClient = new MongoClient("192.168.255.157", 27017);
MongoDatabase database = mongoClient.getDatabase("test");
mongoCollection = database.getCollection("col");
/**
*
* 插入单条
*
*/
@Test
public void testInsertOne()
Document document = new Document();
document.append("userId",0);
document.append("userName", "test0");
document.append("age", 12);
document.append("birthday", new Date());
mongoCollection.insertOne(document);
/**
*
* 简单查询
*
*/
@Test
public void testSimpleQuery()
BasicDBObject basicDBObject = new BasicDBObject();
Calendar instance = Calendar.getInstance();
instance.setTime(new Date());
instance.set(Calendar.HOUR_OF_DAY, 12);
Date time = instance.getTime();
// 虽然mongodb是UTC时间, 但你传Date类型进行查询, 他会自动转换的;
basicDBObject.append("birthday", new BasicBSONObject("$gt", time));
FindIterable<Document> documents = mongoCollection.find(basicDBObject);
MongoCursor<Document> iterator = documents.iterator();
while(iterator.hasNext())
System.out.println(iterator.next().toJson());
/**
*
* 批量插入
*
*/
@Test
public void testInsertMany()
List<Document> documents = new ArrayList<>();
for (int i = 0; i < 100; i++)
Document document = new Document();
document.append("userId",i);
document.append("userName", "test" + i);
document.append("age", random.nextInt(30));
document.append("birthday", new Date());
documents.add(document);
mongoCollection.insertMany(documents);
/**
* 删除全部
*/
@Test
public void testDelete()
// db.collection.remove();
BasicDBObject basicDBObject = new BasicDBObject();
mongoCollection.deleteMany(basicDBObject);
/**
*
* 批量操作
*
*/
@Test
public void bulkWrite()
List<WriteModel<Document>> writeModels = new ArrayList<>();
// 插入
Document document = new Document();
document.append("test", 1);
InsertOneModel insertOneModel = new InsertOneModel(document);
writeModels.add(insertOneModel);
// 修改
Document query = new Document("test", 1);
Document update = new Document("$set", new Document("test", 3));
UpdateManyModel updateManyModel = new UpdateManyModel(query, update);
writeModels.add(updateManyModel);
mongoCollection.bulkWrite(writeModels);
## 3. 驱动工作原理
所有的mongodb驱动都执行三个主要的功能:
- 1. 生成mongodb对象的Id, 默认存储在所有文档的_id字段.
- 2. 驱动会把任意的语言表示的文档对象转换为BSON或者从BSON转换回来.
- 3. 使用Mongodb的自定义协议的TCP Socket连接与数据库通信.
_id 结构: 4B时间 + 机器ID + 进程ID + 计数器
在驱动生成_id的好处之一就是防止自增主键使MongoDB产生性能瓶颈.
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