BAEL-5606 | code for article

jackson-modules/jackson-conversions-3/pom.xml

@@ -42,6 +42,27 @@
             <artifactId>json</artifactId>
             <version>${json.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.mongojack</groupId>
+            <artifactId>mongojack</artifactId>
+            <version>${mongojack.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.mongodb</groupId>
+            <artifactId>mongodb-driver-sync</artifactId>
+            <version>${mongodb-driver.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>de.undercouch</groupId>
+            <artifactId>bson4jackson</artifactId>
+            <version>${bson4jackson.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>de.flapdoodle.embed</groupId>
+            <artifactId>de.flapdoodle.embed.mongo</artifactId>
+            <version>${flapdoodle.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -57,6 +78,10 @@
     <properties>
         <mockserver-netty.version>5.13.2</mockserver-netty.version>
         <json.version>20240303</json.version>
+        <mongojack.version>5.0.3</mongojack.version>
+        <mongodb-driver.version>5.6.1</mongodb-driver.version>
+        <bson4jackson.version>2.18.0</bson4jackson.version>
+        <flapdoodle.version>4.21.0</flapdoodle.version>
     </properties>
 
 </project>

jackson-modules/jackson-conversions-3/src/main/java/com/baeldung/jackson/pojomapping/BsonProductMapper.java

@@ -0,0 +1,48 @@
+package com.baeldung.jackson.pojomapping;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import de.undercouch.bson4jackson.BsonFactory;
+import org.bson.BsonBinaryWriter;
+import org.bson.BsonDocument;
+import org.bson.Document;
+import org.bson.RawBsonDocument;
+import org.bson.codecs.BsonDocumentCodec;
+import org.bson.codecs.EncoderContext;
+import org.bson.io.BasicOutputBuffer;
+
+import java.io.IOException;
+
+public class BsonProductMapper {
+
+    private final ObjectMapper objectMapper;
+
+    public BsonProductMapper() {
+        this.objectMapper = new ObjectMapper(new BsonFactory());
+    }
+
+    public byte[] toBytes(Product product) throws JsonProcessingException {
+        return objectMapper.writeValueAsBytes(product);
+    }
+
+    public Product fromBytes(byte[] bson) throws IOException {
+        return objectMapper.readValue(bson, Product.class);
+    }
+
+    public Document toDocument(Product product) throws IOException {
+        byte[] bytes = toBytes(product);
+        RawBsonDocument bsonDoc = new RawBsonDocument(bytes);
+        return Document.parse(bsonDoc.toJson());
+    }
+
+    public Product fromDocument(Document document) throws IOException {
+        BsonDocument bsonDoc = document.toBsonDocument();
+        BasicOutputBuffer buffer = new BasicOutputBuffer();
+        new BsonDocumentCodec().encode(
+                new BsonBinaryWriter(buffer),
+                bsonDoc,
+                EncoderContext.builder().build()
+        );
+        return fromBytes(buffer.toByteArray());
+    }
+}

jackson-modules/jackson-conversions-3/src/main/java/com/baeldung/jackson/pojomapping/Product.java

@@ -0,0 +1,45 @@
+package com.baeldung.jackson.pojomapping;
+
+import org.mongojack.Id;
+import org.mongojack.ObjectId;
+
+public class Product {
+
+    @ObjectId
+    @Id
+    private String id;
+    private String name;
+    private double price;
+
+    public Product() {
+    }
+
+    public Product(String name, double price) {
+        this.name = name;
+        this.price = price;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+}

jackson-modules/jackson-conversions-3/src/main/java/com/baeldung/jackson/pojomapping/ProductService.java

@@ -0,0 +1,27 @@
+package com.baeldung.jackson.pojomapping;
+
+import com.mongodb.client.MongoDatabase;
+import org.bson.UuidRepresentation;
+import org.mongojack.JacksonMongoCollection;
+
+public class ProductService {
+
+    private final JacksonMongoCollection<Product> collection;
+
+    public ProductService(MongoDatabase database) {
+        this.collection = JacksonMongoCollection.builder()
+                .build(database, "products", Product.class, UuidRepresentation.STANDARD);
+    }
+
+    public void save(Product product) {
+        collection.insertOne(product);
+    }
+
+    public Product findById(String id) {
+        return collection.findOneById(id);
+    }
+
+    public long count() {
+        return collection.countDocuments();
+    }
+}

jackson-modules/jackson-conversions-3/src/test/java/com/baeldung/jackson/pojomapping/BsonProductMapperUnitTest.java

@@ -0,0 +1,82 @@
+package com.baeldung.jackson.pojomapping;
+
+import org.bson.Document;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BsonProductMapperUnitTest {
+
+    private BsonProductMapper mapper;
+    private Product product;
+
+    @BeforeEach
+    void setUp() {
+        mapper = new BsonProductMapper();
+        product = new Product("Test Product", 29.99);
+    }
+
+    @Test
+    void whenSerializingProduct_thenReturnsByteArray() throws IOException {
+        byte[] bytes = mapper.toBytes(product);
+
+        assertNotNull(bytes);
+        assertTrue(bytes.length > 0);
+    }
+
+    @Test
+    void givenSerializedProduct_whenDeserializing_thenReturnsProduct() throws IOException {
+        byte[] bytes = mapper.toBytes(product);
+
+        Product deserializedProduct = mapper.fromBytes(bytes);
+
+        assertEquals(product.getName(), deserializedProduct.getName());
+        assertEquals(product.getPrice(), deserializedProduct.getPrice(), 0.01);
+    }
+
+    @Test
+    void whenConvertingProductToDocument_thenReturnsValidDocument() throws IOException {
+        Document document = mapper.toDocument(product);
+
+        assertNotNull(document);
+        assertEquals(product.getName(), document.getString("name"));
+        assertEquals(product.getPrice(), document.getDouble("price"), 0.01);
+    }
+
+        @Test
+    void whenRoundTrippingProduct_thenDataIsPreserved() throws IOException {
+        Document document = mapper.toDocument(product);
+        Product roundTrippedProduct = mapper.fromDocument(document);
+
+        assertEquals(product.getName(), roundTrippedProduct.getName());
+        assertEquals(product.getPrice(), roundTrippedProduct.getPrice(), 0.01);
+    }
+
+    @Test
+    void givenDocument_whenConvertingToProduct_thenReturnsProduct() throws IOException {
+        Document document = new Document()
+                .append("name", "Document Product")
+                .append("price", 49.99);
+
+        Product convertedProduct = mapper.fromDocument(document);
+
+        assertEquals("Document Product", convertedProduct.getName());
+        assertEquals(49.99, convertedProduct.getPrice(), 0.01);
+    }
+
+    @Test
+    void givenProductWithNullFields_whenSerializing_thenHandlesGracefully() throws IOException {
+
+        Product productWithNulls = new Product();
+        productWithNulls.setPrice(10.0);
+
+        byte[] bytes = mapper.toBytes(productWithNulls);
+        Product deserializedProduct = mapper.fromBytes(bytes);
+
+        assertNull(deserializedProduct.getName());
+        assertEquals(10.0, deserializedProduct.getPrice(), 0.01);
+    }
+}

jackson-modules/jackson-conversions-3/src/test/java/com/baeldung/jackson/pojomapping/ProductServiceLiveTest.java

@@ -0,0 +1,62 @@
+package com.baeldung.jackson.pojomapping;
+
+import com.mongodb.client.MongoClient;
+import com.mongodb.client.MongoClients;
+import de.flapdoodle.embed.mongo.distribution.Version;
+import de.flapdoodle.embed.mongo.transitions.Mongod;
+import de.flapdoodle.embed.mongo.transitions.RunningMongodProcess;
+import de.flapdoodle.reverse.TransitionWalker;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ProductServiceLiveTest {
+
+    private TransitionWalker.ReachedState<RunningMongodProcess> mongodbProcess;
+    private MongoClient mongoClient;
+    private ProductService productService;
+
+    @BeforeEach
+    void setUp() {
+        mongodbProcess = Mongod.instance().start(Version.Main.V5_0);
+        var serverAddress = mongodbProcess.current().getServerAddress();
+
+        mongoClient = MongoClients.create(String.format("mongodb://%s:%d",
+            serverAddress.getHost(), serverAddress.getPort()));
+        productService = new ProductService(mongoClient.getDatabase("testdb"));
+    }
+
+    @AfterEach
+    void tearDown() {
+        if (mongoClient != null) {
+            mongoClient.close();
+        }
+        if (mongodbProcess != null) {
+            mongodbProcess.close();
+        }
+    }
+
+    @Test
+    void whenSavingProduct_thenProductIsPersisted() {
+        Product product = new Product("Laptop", 999.99);
+
+        productService.save(product);
+
+        assertNotNull(product.getId());
+        assertEquals(1, productService.count());
+    }
+
+    @Test
+    void whenSavingProductWithAllFields_thenAllFieldsArePersisted() {
+        Product product = new Product("Full Product", 199.99);
+
+        productService.save(product);
+        Product foundProduct = productService.findById(product.getId());
+
+        assertNotNull(foundProduct.getId());
+        assertEquals("Full Product", foundProduct.getName());
+        assertEquals(199.99, foundProduct.getPrice(), 0.01);
+    }
+}