BAEL-5361 | Article code (#12455)

persistence-modules/java-mongodb-3/src/main/java/com/baeldung/mongo/find/FindWithObjectId.java

@@ -0,0 +1,80 @@
+package com.baeldung.mongo.find;
+
+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 org.bson.Document;
+import org.bson.types.ObjectId;
+
+import static com.mongodb.client.model.Filters.eq;
+
+public class FindWithObjectId {
+
+    private static final String OBJECT_ID_FIELD = "_id";
+
+    private static MongoClient mongoClient;
+    private static MongoDatabase database;
+    private static MongoCollection<Document> collection;
+    private static String collectionName;
+    private static String databaseName;
+
+    public static void setUp() {
+        if (mongoClient == null) {
+            mongoClient = new MongoClient("localhost", 27017);
+
+            databaseName = "baeldung";
+            collectionName = "employee";
+
+            database = mongoClient.getDatabase(databaseName);
+            collection = database.getCollection(collectionName);
+        }
+    }
+
+    public static void retrieveAllDocumentsUsingFindWithObjectId() {
+        Document document = collection.find()
+          .first();
+        System.out.println(document);
+
+        FindIterable<Document> documents = collection.find(eq(OBJECT_ID_FIELD, document.get(OBJECT_ID_FIELD)));
+
+        MongoCursor<Document> cursor = documents.iterator();
+        while (cursor.hasNext()) {
+            System.out.println(cursor.next());
+        }
+    }
+
+    public static void retrieveFirstDocumentWithObjectId() {
+        Document document = collection.find()
+          .first();
+        System.out.println(document);
+
+        FindIterable<Document> documents = collection.find(eq(OBJECT_ID_FIELD, document.get(OBJECT_ID_FIELD)));
+        Document queriedDocument = documents.first();
+
+        System.out.println(queriedDocument);
+    }
+
+    public static void retrieveDocumentWithRandomObjectId() {
+        FindIterable<Document> documents = collection.find(eq(OBJECT_ID_FIELD, new ObjectId()));
+        Document queriedDocument = documents.first();
+
+        if (queriedDocument != null) {
+            System.out.println(queriedDocument);
+        } else {
+            System.out.println("No documents found");
+        }
+    }
+
+    public static void main(String args[]) {
+
+        setUp();
+
+        retrieveAllDocumentsUsingFindWithObjectId();
+
+        retrieveFirstDocumentWithObjectId();
+
+        retrieveDocumentWithRandomObjectId();
+    }
+}

persistence-modules/java-mongodb-3/src/test/java/com/baeldung/mongo/find/FindWithObjectIdLiveTest.java

@@ -0,0 +1,87 @@
+package com.baeldung.mongo.find;
+
+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 org.bson.Document;
+import org.bson.types.ObjectId;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+
+import static com.mongodb.client.model.Filters.eq;
+import static org.junit.Assert.*;
+
+public class FindWithObjectIdLiveTest {
+
+    private static final String OBJECT_ID_FIELD = "_id";
+
+    private static MongoClient mongoClient;
+    private static MongoDatabase database;
+    private static MongoCollection<Document> collection;
+    private static final String DATASET_JSON = "/employee.json";
+
+    @BeforeClass
+    public static void setUp() throws IOException {
+        if (mongoClient == null) {
+            mongoClient = new MongoClient("localhost", 27017);
+
+            database = mongoClient.getDatabase("baeldung");
+            collection = database.getCollection("employee");
+
+            collection.drop();
+
+            InputStream is = FindOperationLiveTest.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 givenEmployeeCollection_whenFetchingDocumentsUsingObjectId_thenCheckingForDocuments() {
+        Document employee = collection.find()
+          .first();
+        ObjectId objectId = (ObjectId) employee.get(OBJECT_ID_FIELD);
+
+        FindIterable<Document> documents = collection.find(eq(OBJECT_ID_FIELD, objectId));
+        MongoCursor<Document> cursor = documents.iterator();
+
+        assertNotNull(cursor);
+        assertTrue(cursor.hasNext());
+    }
+
+    @Test
+    public void givenEmployeeCollection_whenFetchingFirstDocumentUsingObjectId_thenCheckingForDocument() {
+        Document employee = collection.find()
+          .first();
+        ObjectId objectId = (ObjectId) employee.get(OBJECT_ID_FIELD);
+
+        Document queriedEmployee = collection.find(eq(OBJECT_ID_FIELD, objectId))
+          .first();
+
+        assertNotNull(queriedEmployee);
+        assertEquals(employee.get(OBJECT_ID_FIELD), queriedEmployee.get(OBJECT_ID_FIELD));
+    }
+
+    @Test
+    public void givenEmployeeCollection_whenFetchingUsingRandomObjectId_thenCheckingForDocument() {
+        Document employee = collection.find(eq(OBJECT_ID_FIELD, new ObjectId()))
+          .first();
+
+        assertNull(employee);
+    }
+
+    @AfterClass
+    public static void cleanUp() {
+        mongoClient.close();
+    }
+}