功能需求:连接mongodb数据库抓取指定字段值数据保存至mysql数据库;第一次使用，如果有更好方式还请各位指正.具体代码如下:

import com.mongodb.MongoClient;
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.types.Decimal128;
import org.junit.Test;

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

public class MongodbTest {

    @Test
    public static void testQueryMongoDBCollection(){

        MongoClient mongoClient = new MongoClient("IP",27017);
        //连接到数据库
        MongoDatabase mongoDatabase = mongoClient.getDatabase("History");

        // 获取集合
        MongoCollection collection = mongoDatabase.getCollection("HistoryData");

        //条件查询
        MongoCursor mongoCursor  = collection.find().filter(
                Filters.and(
                        Filters.eq("BuildId", "000001G001"),//ID
                        Filters.eq("MeterCode", "T005001"),//编号
                        Filters.eq("Time", "2022-08-31 11:25:00")//日期
                        )).iterator();

        List<Object> objects = new ArrayList<Object>();
        while (mongoCursor.hasNext()) {
            objects.add(mongoCursor.next());
            Document document = (Document) objects.get(0);
            //获取mongodb中字段名为S的值转为double,主要是为了保存到mysql数据库;
            Decimal128 decimal128 = (Decimal128) document.get("S");
            double  doubleValue = decimal128.doubleValue();
            System.out.println(doubleValue);
        }

    }

    public static void main(String[] args) {
        testQueryMongoDBCollection();
    }


}

打印结果: