既然有MySQL了，为什么还要有MongoDB？

systemLog:
    destination: file
    logAppend: true
    path: D:\Program Files\mongodb\data\logs\mongod.log
storage:
    dbPath: D:\Program Files\mongodb\data\db

D:\Program Files\mongodb\bin>mongod --version
db version v5.0.14
Build Info: {
    "version": "5.0.14",
    "gitVersion": "1b3b0073a0b436a8a502b612f24fb2bd572772e5",
    "modules": [],
    "allocator": "tcmalloc",
    "environment": {
        "distmod": "windows",
        "distarch": "x86_64",
        "target_arch": "x86_64"
    }
}

<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongo-java-driver</artifactId>
    <version>3.8.2</version>
</dependency>

package com.example.demo.utils;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

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

import com.mongodb.MongoClient;
import com.mongodb.MongoCredential;
import com.mongodb.ServerAddress;
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;

public class MongoDBUtil {

    private static MongoClient mongoClient;

    private static MongoClient mongoClientIdentify;

    /**
     * 不通过认证获取连接数据库对象
     */
    public static MongoDatabase getNoIdentifyConnect(String host, int port, String dbaseName){
        // 连接mongodb服务
        MongoDBUtil.mongoClient = new MongoClient(host, port);

        // 连接数据库
        MongoDatabase mongoDatabase = MongoDBUtil.mongoClient.getDatabase(dbaseName);

        // 返回连接数据库对象
        return mongoDatabase;
    }

    /**
     * 通过连接认证获取MongoDB连接
     */
    public static MongoDatabase getIdentifyConnect(String host, int port, String dbaseName, String userName, String password){

        List<ServerAddress> adds = new ArrayList<ServerAddress>();

        ServerAddress serverAddress = new ServerAddress(host, port);
        adds.add(serverAddress);

        List<MongoCredential> credentials = new ArrayList<>();

        MongoCredential mongoCredential = MongoCredential.createScramSha1Credential(userName, dbaseName, password.toCharArray());
        credentials.add(mongoCredential);

        // 通过连接认证获取MongoDB连接
        MongoDBUtil.mongoClientIdentify = new MongoClient(adds, credentials);

        MongoDatabase mongoDatabase = MongoDBUtil.mongoClientIdentify.getDatabase(dbaseName);

        return mongoDatabase;
    }

    /**
     * 关闭连接
     */
    public static void closeNoIdentifyConnect (){
        MongoDBUtil.mongoClient.close();
    }

    /**
     * 关闭连接
     */
    public static void closeIdentifyConnect (){
        MongoDBUtil.mongoClientIdentify.close();
    }

    /**
     * 插入一个文档
     */
    public static void insertOne (Map<String, Object> data, MongoDatabase mongoDatabase, String col){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);

        //创建文档
        Document document = new Document();

        for (Map.Entry<String, Object> m : data.entrySet()) {
            document.append(m.getKey(), m.getValue()).append(m.getKey(), m.getValue());
        }

        //插入一个文档
        collection.insertOne(document);
    }

    /**
     * 插入多个文档
     */
    public static void insertMany (List<Map<String, Object>> listData, MongoDatabase mongoDatabase, String col){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);

        //要插入的数据
        List<Document> list = new ArrayList<>();
        for (Map<String, Object> data : listData) {
            //创建文档
            Document document = new Document();

            for (Map.Entry<String, Object> m : data.entrySet()) {
                document.append(m.getKey(), m.getValue());
            }
            list.add(document);
        }

        //插入多个文档
        collection.insertMany(list);
    }

    /**
     * 删除匹配到的第一个文档
     */
    public static void delectOne (String col, String key, Object value, MongoDatabase mongoDatabase){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);
        //申明删除条件
        Bson filter = Filters.eq(key, value);
        //删除与筛选器匹配的单个文档
        collection.deleteOne(filter);
    }

    /**
     * 删除匹配的所有文档
     */
    public static void deleteMany (String col, String key, Object value, MongoDatabase mongoDatabase){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);
        //申明删除条件
        Bson filter = Filters.eq(key, value);
        //删除与筛选器匹配的所有文档
        collection.deleteMany(filter);
    }

    /**
     * 删除集合中所有文档
     */
    public static void deleteAllDocument(String col, MongoDatabase mongoDatabase){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);
        collection.deleteMany(new Document());
    }

    /**
     * 删除文档和集合。
     */
    public static void deleteAllCollection(String col, MongoDatabase mongoDatabase){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);
        collection.drop();
    }

    /**
     * 修改单个文档，修改过滤器筛选出的第一个文档
     *
     * @param col 修改的集合
     * @param key 修改条件的键
     * @param value 修改条件的值
     * @param eqKey 要修改的键，如果eqKey不存在，则新增记录
     * @param eqValue 要修改的值
     * @param mongoDatabase 连接数据库对象
     */
    public static void updateOne (String col, String key, Object value,String eqKey, Object eqValue, MongoDatabase mongoDatabase){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);
        //修改过滤器
        Bson filter = Filters.eq(key, value);
        //指定修改的更新文档
        Document document = new Document("$set", new Document(eqKey, eqValue));
        //修改单个文档
        collection.updateOne(filter, document);
    }

    /**
     * 修改多个文档
     *
     * @param col 修改的集合
     * @param key 修改条件的键
     * @param value 修改条件的值
     * @param eqKey 要修改的键，如果eqKey不存在，则新增记录
     * @param eqValue 要修改的值
     * @param mongoDatabase 连接数据库对象
     */
    public static void updateMany (String col, String key, Object value, String eqKey, Object eqValue, MongoDatabase mongoDatabase){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);
        //修改过滤器
        Bson filter = Filters.eq(key, value);
        //指定修改的更新文档
        Document document = new Document("$set", new Document(eqKey, eqValue));
        //修改多个文档
        collection.updateMany(filter, document);
    }

    /**
     * 查找集合中的所有文档
     */
    public static MongoCursor<Document> find (String col, MongoDatabase mongoDatabase){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);
        //查找集合中的所有文档
        FindIterable<Document> findIterable = collection.find();
        MongoCursor<Document> cursorIterator = findIterable.iterator();
        return cursorIterator;
    }

    /**
     * 按条件查找集合中文档
     */
    public static MongoCursor<Document> Filterfind (String col,String key, Object value, MongoDatabase mongoDatabase){
        //获取集合
        MongoCollection<Document> collection = mongoDatabase.getCollection(col);
        //指定查询过滤器
        Bson filter = Filters.eq(key, value);

        //指定查询过滤器查询
        FindIterable<Document> findIterable = collection.find(filter);
        MongoCursor<Document> cursorIterator = findIterable.iterator();
        return cursorIterator;
    }
}

<dependency>
   <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
</dependency>

package com.example.demo.utils;

import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;
import org.junit.Test;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MongoDBTest {

    // 获取数据库连接对象
    MongoDatabase mongoDatabase = MongoDBUtil.getNoIdentifyConnect("127.0.0.1", 27017, "test");

    @Test
    public void insertOne(){
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("姓名", "哪吒编程");
        map.put("性别", "男");
        map.put("年龄", 18);
        MongoDBUtil.insertOne(map, mongoDatabase, "worker");
        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void insertMany(){
        Map<String, Object> map1 = new HashMap<String, Object>();
        map1.put("姓名", "哪吒编程2");
        map1.put("性别", "男");
        map1.put("年龄", 18);
        Map<String, Object> map2 = new HashMap<String, Object>();
        map2.put("姓名", "妲己");
        map2.put("性别", "女");
        map2.put("年龄", 18);
        List<Map<String, Object>> listData = new ArrayList<>();
        listData.add(map1);
        listData.add(map2);
        MongoDBUtil.insertMany(listData, mongoDatabase, "worker");
        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void delectOne(){
        MongoDBUtil.delectOne("worker", "姓名", "妲己", mongoDatabase);

        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void deleteMany(){

        MongoDBUtil.deleteMany("worker", "姓名", "哪吒编程", mongoDatabase);
        MongoDBUtil.deleteMany("worker", "姓名", "妲己", mongoDatabase);

        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void deleteAllDocument(){
        MongoDBUtil.deleteAllDocument("worker", mongoDatabase);

        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void deleteAllCollection(){

        MongoDBUtil.deleteAllCollection("worker", mongoDatabase);

        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void updateOne(){

        MongoDBUtil.updateOne("worker", "姓名", "哪吒编程2","姓名", "哪吒编程", mongoDatabase);

        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void updateMany(){

        MongoDBUtil.updateMany("worker", "姓名", "哪吒编程2","姓名", "哪吒编程", mongoDatabase);

        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void find(){
        MongoCursor<Document> mongoCursor = MongoDBUtil.find("worker", mongoDatabase);

        while (mongoCursor.hasNext()) {
            Document document = mongoCursor.next();
            System.out.println(document + "  size: " + document.size());
        }
        MongoDBUtil.closeNoIdentifyConnect();
    }

    @Test
    public void filterfind(){
        MongoCursor<Document> mongoCursor = MongoDBUtil.Filterfind("worker", "姓名", "哪吒编程", mongoDatabase);

        while (mongoCursor.hasNext()) {
            Document document = mongoCursor.next();
            System.out.println(document + "  size: " + document.size());
        }
        MongoDBUtil.closeNoIdentifyConnect();
    }
}