实现java连接mongoDB（简单封装）

　　最近要完成一个登陆注册的功能，加上刚刚学了MongoDB，就想试一试，查了很多博客，都不能找到一篇完整的用例，只有自己折腾下了。这里我们需要加载一个jar包，我用的是mongo-java-driver-3.8.0.jar，主要用到的是client下的相关组件。

package com.amyyang.mongodb;

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.Filters;

import org.bson.Document;
import org.bson.conversions.Bson;

public class MongodbHelper {
	/* 建立连接 */
	public static MongoDatabase setConnection() {
		try {
			// 	连接MongoDB服务
			@SuppressWarnings("resource")
			MongoClient mongoClient=new MongoClient("localhost",27017);
			// 连接到数据库
			MongoDatabase mongoDatabase=mongoClient.getDatabase("test");
			System.out.println("successfully connecting"+mongoClient);
			return mongoDatabase;
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		return null;
	}
	/* 默认collection */
	public static String userinfoCollection() {
		return "info";
	}
	@SuppressWarnings({ })
	/* 查找JSON */
	public static boolean checkinfo(String user,String password) {
		boolean result=false;
		if(setConnection()!=null) {
			MongoDatabase mongoDatabase=setConnection();
			MongoCollection<Document> collection=mongoDatabase.getCollection(userinfoCollection());
			// "userid","userpassword"是我info集合下的字段名
			Bson filter=Filters.eq("userid",user);
			FindIterable<Document> findIterable=collection.find(filter);
			MongoCursor<Document> cursor=findIterable.iterator();
			while(cursor.hasNext()) {
				Bson refilter=Filters.eq("userpasswd",password);
				FindIterable<Document> refindIterable=collection.find(refilter);
				MongoCursor<Document> recursor=refindIterable.iterator();
				while(recursor.hasNext()) {
					System.out.println(recursor.next());
					result=true;
					return true;
				}
			}
		}else {
			// 连接MongeDB失败
			System.out.println("Connection failure");
			return false;
		}
		return result;
	}
	/* 插入JSON */
	public static boolean insertinfo(String user,String password) {
		if(setConnection()!=null) {
			MongoDatabase mongoDatabase=setConnection();
			// System.out.println(mongoDatabase);
			MongoCollection<Document> collection=mongoDatabase.getCollection(userinfoCollection());
			// System.out.println(userinfoCollection());
			Document document=new Document("userid",user).append("userpasswd", password);
			collection.insertOne(document);
			return true;
		}else {
			// 连接MongeDB失败
			System.out.println("Connection failure");
			return false;
		}	
	}
	/* 更新JSON */
	public static boolean updateinfo(String user,String newpasswd) {
		if(setConnection()!=null) {
			MongoDatabase mongoDatabase=setConnection();
			MongoCollection<Document> collection=mongoDatabase.getCollection(userinfoCollection());
			Bson filter=Filters.eq("userid",user);
			Document document=new Document("$set",new Document("userpasswd",newpasswd));
			collection.updateOne(filter, document);
			return true;
		}else {
			// 连接MongeDB失败
			System.out.println("Connection failure");
			return false;
		}
	}
	// 进行简单测试
	public static void main(String[] args) {
		setConnection();
		boolean rs1=checkinfo("admin", "passwd1");
		System.out.print(rs1);
		boolean rs2=insertinfo("newadmin", "newpasswd");
		System.out.print(rs2);
		boolean rs3=updateinfo("admin", "passwd");
		System.out.print(rs3);
	}
}

　　

　　到这我简单的对mongodb的操作进行了封装，方便后面servlet的请求验证。2020马上要来了，祝大家新年快乐，万事如意！