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BAEL-5357: Retrieve a Value from MongoDB by Its Key Name (#12005)

This commit is contained in:
Kapil Khandelwal 2022-04-02 03:01:23 +05:30 committed by GitHub
parent b1c60e9093
commit 007271ec3b
3 changed files with 236 additions and 0 deletions
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118
persistence-modules/java-mongodb-2/src/main/java/com/baeldung/mongo/RetrieveValue.java Normal file
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package com.baeldung.mongo;
import static com.mongodb.client.model.Aggregates.project;
import static com.mongodb.client.model.Projections.fields;
import java.util.ArrayList;
import java.util.Arrays;
import org.bson.Document;
import org.bson.conversions.Bson;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.MongoClient;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Projections;
public class RetrieveValue {
private static MongoClient mongoClient;
private static MongoDatabase database;
private static String testCollectionName;
private static String databaseName;
public static void setUp() {
if (mongoClient == null) {
mongoClient = new MongoClient("localhost", 27017);
}
databaseName = "baeldung";
testCollectionName = "travel";
}
public static void retrieveValueUsingFind() {
DB database = mongoClient.getDB(databaseName);
DBCollection collection = database.getCollection(testCollectionName);
BasicDBObject queryFilter = new BasicDBObject();
BasicDBObject projection = new BasicDBObject();
projection.put("passengerId", 1);
projection.put("_id", 0);
DBCursor dbCursor = collection.find(queryFilter, projection);
while (dbCursor.hasNext()) {
System.out.println(dbCursor.next());
}
}
public static void retrieveValueUsingAggregation() {
ArrayList<Document> response = new ArrayList<>();
ArrayList<Bson> pipeline = new ArrayList<>(Arrays.asList(
project(fields(Projections.exclude("_id"), Projections.include("passengerId")))));
database = mongoClient.getDatabase(databaseName);
database.getCollection(testCollectionName)
.aggregate(pipeline)
.allowDiskUse(true)
.into(response);
System.out.println("response:- " + response);
}
public static void retrieveValueAggregationUsingDocument() {
ArrayList<Document> response = new ArrayList<>();
ArrayList<Document> pipeline = new ArrayList<>(Arrays.asList(new Document("$project", new Document("passengerId", 1L))));
database = mongoClient.getDatabase(databaseName);
database.getCollection(testCollectionName)
.aggregate(pipeline)
.allowDiskUse(true)
.into(response);
System.out.println("response:- " + response);
}
public static void main(String args[]) {
//
// Connect to cluster (default is localhost:27017)
//
setUp();
//
// Fetch the data using find query with projected fields
//
retrieveValueUsingFind();
//
// Fetch the data using aggregate pipeline query with projected fields
//
retrieveValueUsingAggregation();
//
// Fetch the data using aggregate pipeline document query with projected fields
//
retrieveValueAggregationUsingDocument();
}
}

114
persistence-modules/java-mongodb-2/src/test/java/com/baeldung/mongo/RetrieveValueLiveTest.java Normal file
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package com.baeldung.mongo;
import static com.mongodb.client.model.Aggregates.project;
import static com.mongodb.client.model.Projections.fields;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import org.bson.Document;
import org.bson.conversions.Bson;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Filters;
import com.mongodb.client.model.Projections;
public class RetrieveValueLiveTest {
private static MongoClient mongoClient;
private static MongoDatabase database;
private static MongoCollection<Document> collection;
private static final String DATASET_JSON = "/travel.json";
private static DB db;
private static DBCollection dbCollection;
@BeforeClass
public static void setup() throws IOException {
if (mongoClient == null) {
mongoClient = new MongoClient("localhost", 27017);
database = mongoClient.getDatabase("baeldung");
db = mongoClient.getDB("baeldung");
dbCollection = db.getCollection("travel");
collection = database.getCollection("travel");
collection.drop();
InputStream is = BulkOperationLiveTest.class.getResourceAsStream(DATASET_JSON);
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
reader.lines()
.forEach(line -> collection.insertOne(Document.parse(line)));
reader.close();
}
}
@Test
public void givenTravelCollection_whenfetchUsingFindOperations_thenCheckingForDocument() {
BasicDBObject queryFilter = new BasicDBObject();
BasicDBObject projection = new BasicDBObject();
projection.put("passengerId", 1);
projection.put("_id", 0);
DBCursor dbCursor = dbCollection.find(queryFilter, projection);
while (dbCursor.hasNext()) {
System.out.println(dbCursor.next());
}
Document travelDetail = collection.find(Filters.eq("passengerId", 145))
.first();
assertNotNull(travelDetail);
assertFalse(travelDetail.isEmpty());
}
@Test
public void givenTravelCollection_whenfetchUsingAggregationOperations_thenCheckingForDocument() {
ArrayList<Document> response = new ArrayList<>();
ArrayList<Bson> pipeline = new ArrayList<>(Arrays.asList(project(fields(Projections.exclude("_id"), Projections.include("passengerId")))));
collection.aggregate(pipeline)
.allowDiskUse(true)
.into(response);
Document travelDetail = collection.find(Filters.eq("passengerId", 145))
.first();
assertNotNull(travelDetail);
assertFalse(travelDetail.isEmpty());
}
@Test
public void givenTravelCollection_whenfetchUsingAggregationUsingDocumentOperations_thenCheckingForDocument() {
ArrayList<Document> response = new ArrayList<>();
ArrayList<Document> pipeline = new ArrayList<>(Arrays.asList(new Document("$project", new Document("passengerId", 1L))));
collection.aggregate(pipeline)
.allowDiskUse(true)
.into(response);
Document travelDetail = collection.find(Filters.eq("passengerId", 145))
.first();
assertNotNull(travelDetail);
assertFalse(travelDetail.isEmpty());
}
@AfterClass
public static void cleanUp() {
mongoClient.close();
}
}

4
persistence-modules/java-mongodb-2/src/test/resources/travel.json Normal file
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{ "passengerId":145, "passengerName":"Nathan Green", "passengerAge":25, "sourceStation":"London","destinationStation":"Birmingham","seatType":"Slepper","emailAddress":"nathongreen12@gmail.com"}
{ "passengerId":148,"passengerName":"Kevin Joseph","passengerAge":28,"sourceStation":"Manchester","destinationStation":"London","seatType":"Slepper","emailAddress":"kevin13@gmail.com"}
{"passengerId":154,"passengerName":"Sheldon burns","passengerAge":26,"sourceStation":"Cambridge","destinationStation":"Leeds","seatType":"Slepper","emailAddress":"sheldonnn160@gmail.com"}
{"passengerId":168,"passengerName":"Jack Ferguson","passengerAge":24,"sourceStation":"Cardiff","destinationStation":"Coventry","seatType":"Slepper","emailAddress":"jackfergusion9890@gmail.com"}