MongoDB的简单介绍

其他 2018-12-06 10:31:40 阅读次数: 0

MongoDB的安装和启动就不介绍了;

创建maven工程,引入依赖

  <dependencies>
    <dependency>
        <groupId>org.mongodb</groupId>
        <artifactId>mongodb-driver</artifactId>
        <version>3.4.1</version>
    </dependency>
  </dependencies>

创建实体类对象StudentDao

package cn.liuzhengwei.demo;
import org.bson.Document;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
/**
 * 数据访问层
 * @author Administrator
 */
public class StudentDao {

	public void save(String name,String sex,double age,String address){
		MongoDatabase database = MongoManager.getDatabase();
		MongoCollection<Document> collection = database.getCollection("student2");
		Document docment=new Document();
		docment.put("name", name);
		docment.put("sex", sex);		
		docment.put("age", age);
		docment.put("address", address);
		collection.insertOne(docment);
	}	
}

MongoClient 被设计为线程安全的类，也就是我们在使用该类时不需要考虑并发的情况，这样我们可以考虑把MongoClient 做成一个静态变量，为所有线程公用，不必每次都销毁。这样可以极大提高执行效率。实际上，这是MongoDB提供的内置的连接池来实现的。    

  我们要创建一个“管理类”，相当于我们原来的BaseDao

package cn.liuzhengwei.demo;
import com.mongodb.MongoClient;
import com.mongodb.MongoClientOptions;
import com.mongodb.MongoClientOptions.Builder;
import com.mongodb.WriteConcern;
import com.mongodb.client.MongoDatabase;

public class MongoManager {

	private static MongoClient mongoClient=null;
	
	//对mongoClient初始化
	private static void init(){		
		//连接池选项
		Builder builder = new MongoClientOptions.Builder();//选项构建者	
		builder.connectTimeout(5000);//设置连接超时时间
		builder.socketTimeout(5000);//读取数据的超时时间
		builder.connectionsPerHost(30);//每个地址最大请求数		
		builder.writeConcern(WriteConcern.NORMAL);//写入策略，仅抛出网络异常
		MongoClientOptions options = builder.build();
		mongoClient=new MongoClient("127.0.0.1",options);	
	}
	
	public static MongoDatabase getDatabase(){
		if(mongoClient==null){
			init();
		}		
		return mongoClient.getDatabase(数据库名);
	}
}

下面是写入策略。

WriteConcern.NONE:没有异常抛出

WriteConcern.NORMAL:仅抛出网络错误异常，没有服务器错误异常

WriteConcern.SAFE:抛出网络错误异常、服务器错误异常；并等待服务器完成写操作。

WriteConcern.MAJORITY: 抛出网络错误异常、服务器错误异常；并等待一个主服务器完成写操作。

WriteConcern.FSYNC_SAFE: 抛出网络错误异常、服务器错误异常；写操作等待服务器将数据刷新到磁盘。

WriteConcern.JOURNAL_SAFE:抛出网络错误异常、服务器错误异常；写操作等待服务器提交到磁盘的日志文件。

WriteConcern.REPLICAS_SAFE:抛出网络错误异常、服务器错误异常；等待至少2台服务器完成写操作。

编写测试类 插入2000条数据

package cn.liuzhengwei.demo;
import java.util.Date;
public class TestPool {

	public static void main(String[] args) {
		long startTime = new Date().getTime();//开始时间
		
		StudentDao studentDao=new StudentDao();
		for(int i=0;i<20000;i++){
			studentDao.save("测试"+i, "男", 25.0, "测试地址"+i);
		}
		long endTime = new Date().getTime();//完成时间
		System.out.println("完成时间："+(endTime-startTime)+"毫秒");
	}
}

各种查询方式汇总

package com.liuzhengwei.demo;

import com.mongodb.BasicDBObject;
import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.result.UpdateResult;
import org.bson.Document;
import org.junit.Test;

import java.util.Arrays;
import java.util.HashMap;
import java.util.regex.Pattern;


public class Demo {

    /**
     * 查询全部记录
     */
    @Test
    public void demotest(){

        MongoClient client=new MongoClient();//创建连接对象
        MongoDatabase database = client.getDatabase("db");//获取数据库
        MongoCollection<Document> collection = database.getCollection("student");//获取集合

        FindIterable<Document> list = collection.find();//获取文档集合
        for( Document doc: list){//遍历集合中的文档输出数据
            System.out.println("name:"+ doc.getString("name") );
            System.out.println("sex:"+ doc.getString("sex") );
            System.out.println("age:"+ doc.getDouble("age") );//默认为浮点型
            System.out.println("address:"+ doc.getString("address") );
            System.out.println("--------------------------");
        }
    }

    /**
     * 条件查询
     */
    @Test
    public void  demo2(){
        MongoClient client=new MongoClient();//创建连接对象
        MongoDatabase database = client.getDatabase("db");//获取数据库
        MongoCollection<Document> collection = database.getCollection("student");//获取集合
        //构建查询条件
        BasicDBObject bson = new BasicDBObject ("name","白龙马");
        FindIterable <Document> documents = collection.find (bson);
        for (Document doc : documents) {
            System.out.println("name:"+ doc.getString("name") );
            System.out.println("sex:"+ doc.getString("sex") );
            System.out.println("age:"+ doc.getDouble("age") );//默认为浮点型
            System.out.println("address:"+ doc.getString("address") );
            System.out.println("--------------------------");
        }
    }

    /**
     * 构建模糊查询条件是通过正则表达式的方式来实现的
     *  完全匹配Pattern pattern = Pattern.compile("^name$");
     *  右匹配Pattern pattern = Pattern.compile("^.*name$");
     *  左匹配Pattern pattern = Pattern.compile("^name.*$");
     *  模糊匹配Pattern pattern = Pattern.compile("^.*name.*$");
     */
    @Test
    public void demo3(){
        MongoClient client=new MongoClient();//创建连接对象
        MongoDatabase database = client.getDatabase("db");//获取数据库
        MongoCollection<Document> collection = database.getCollection("student");//获取集合
        //构建模糊查询条件
        //Pattern pattern = Pattern.compile ("^白龙马$");
        Pattern pattern = Pattern.compile ("^.*白.*$");
        BasicDBObject bson = new BasicDBObject ("name", pattern);
        FindIterable <Document> list = collection.find (bson);
        for (Document doc : list) {
            System.out.println("name:"+ doc.getString("name") );
            System.out.println("sex:"+ doc.getString("sex") );
            System.out.println("age:"+ doc.getDouble("age") );//默认为浮点型
            System.out.println("address:"+ doc.getString("address") );
            System.out.println("--------------------------");
        }
    }

    /**
     * 大于小于
     *  条件嵌套
     */

    @Test
    public void  demo4(){
        MongoClient client=new MongoClient();//创建连接对象
        MongoDatabase database = client.getDatabase("db");//获取数据库
        MongoCollection<Document> collection = database.getCollection("student");//获取集合

        BasicDBObject $lt = new BasicDBObject ("$lte", 20);//小于 gt大于 gte大于等于 lte小于等于
        BasicDBObject bson = new BasicDBObject ("age", $lt);

        FindIterable <Document> list = collection.find (bson);
        for (Document doc : list) {
            System.out.println("name:"+ doc.getString("name") );
            System.out.println("sex:"+ doc.getString("sex") );
            System.out.println("age:"+ doc.getDouble("age") );//默认为浮点型
            System.out.println("address:"+ doc.getString("address") );
            System.out.println("--------------------------");
        }
    }

    /**
     * 条件连接--并且
     *
     */
    @Test
    public  void  demo5(){
        MongoClient client = new MongoClient ();
        MongoDatabase database = client.getDatabase ("db");
        MongoCollection <Document> collection = database.getCollection ("student");

        BasicDBObject gte = new BasicDBObject ("age", new BasicDBObject ("$gte",20));
        BasicDBObject lte = new BasicDBObject ("age", new BasicDBObject("$lt",30));
        BasicDBObject bson = new BasicDBObject ("$and", Arrays.asList (gte, lte));
        FindIterable <Document> list = collection.find (bson);
        for (Document doc : list) {
            System.out.println("name:"+ doc.getString("name") );
            System.out.println("sex:"+ doc.getString("sex") );
            System.out.println("age:"+ doc.getDouble("age") );//默认为浮点型
            System.out.println("address:"+ doc.getString("address") );
            System.out.println("--------------------------");
        }


    }
    /**
     * 条件连接--或者
     *
     */
    @Test
    public  void  demo6(){
        System.out.println ("aaaaaaaaa");


        MongoClient client = new MongoClient ();
        MongoDatabase database = client.getDatabase ("db");
        MongoCollection <Document> collection = database.getCollection ("student");

        BasicDBObject bson1 = new BasicDBObject ("age", new BasicDBObject ("$lte",20));
        BasicDBObject bson2 = new BasicDBObject ("sex", "女");
        BasicDBObject bson = new BasicDBObject ("$or", Arrays.asList (bson1, bson2));
        FindIterable <Document> list = collection.find (bson);
        for (Document doc : list) {
            System.out.println("name:"+ doc.getString("name") );
            System.out.println("sex:"+ doc.getString("sex") );
            System.out.println("age:"+ doc.getDouble("age") );//默认为浮点型
            System.out.println("address:"+ doc.getString("address") );
            System.out.println("--------------------------");
        }
    }

    /**
     * 增
     * insertOne方法来插入文档  updateMany方法用于修改符合条件的所有记录
                                updateOne方法用于修改符合条件的第一条记录
     */
    @Test
    public  void  demo7(){
        MongoClient client = new MongoClient ();
        MongoDatabase database = client.getDatabase ("db");
        MongoCollection <Document> collection = database.getCollection ("student");
        //创建集合封装对象
        HashMap <String, Object> map = new HashMap <> ();
        map.put ("name","铁扇公主");
        map.put ("age",23.0);
        map.put ("sex","女");
        map.put ("address","牛头山");
        Document document = new Document (map);
        collection.insertOne (document);//插入一条数据
        //collection.insertMany(documents);//一次性插入多条文档
    }

    /**
     * 删除文档
     *
     */
    @Test
    public void demo8(){
        MongoClient client = new MongoClient ();
        MongoDatabase database = client.getDatabase ("db");
        MongoCollection <Document> collection = database.getCollection ("student");
        BasicDBObject bson = new BasicDBObject ("name", "铁扇公主");
        collection.deleteOne (bson);
    }

    /**
     * 修改
     *
     *
     */

    @Test
    public  void demo9(){

        MongoClient client = new MongoClient ();
        MongoDatabase database = client.getDatabase ("db");
        MongoCollection <Document> collection = database.getCollection ("student");
        BasicDBObject bson = new BasicDBObject ("name", "铁扇公主");
        BasicDBObject bson2 = new BasicDBObject ("$set", new BasicDBObject ("address", "南山"));
        collection.updateMany (bson, bson2);

    }
}

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