BAEL-3943 Bson to json (#9079)

persistence-modules/java-mongodb/README.md

@@ -10,3 +10,4 @@ This module contains articles about MongoDB in Java.
 - [Geospatial Support in MongoDB](https://www.baeldung.com/mongodb-geospatial-support)
 - [Introduction to Morphia – Java ODM for MongoDB](https://www.baeldung.com/mongodb-morphia)
 - [MongoDB Aggregations Using Java](https://www.baeldung.com/java-mongodb-aggregations)
+- [MongoDB BSON to JSON](https://www.baeldung.com/bson-to-json)

persistence-modules/java-mongodb/src/main/java/com/baeldung/morphia/domain/Book.java

@@ -1,5 +1,7 @@
 package com.baeldung.morphia.domain;
 
+import java.time.LocalDate;
+import java.time.LocalDateTime;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -29,28 +31,13 @@ public class Book {
     private double cost;
     @Reference
     private Set<Book> companionBooks;
+    @Property
+    private LocalDateTime publishDate;
 
     public Book() {
 
     }
 
-    public String getTitle() {
-        return title;
-    }
-
-    public String getAuthor() {
-        return author;
-    }
-
-    public double getCost() {
-        return cost;
-    }
-
-    public void addCompanionBooks(Book book) {
-        if (companionBooks != null)
-            this.companionBooks.add(book);
-    }
-
     public Book(String isbn, String title, String author, double cost, Publisher publisher) {
         this.isbn = isbn;
         this.title = title;
@@ -60,6 +47,71 @@ public class Book {
         this.companionBooks = new HashSet<>();
     }
 
+    // Getters and setters ...
+    public String getIsbn() {
+        return isbn;
+    }
+
+    public Book setIsbn(String isbn) {
+        this.isbn = isbn;
+        return this;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public Book setTitle(String title) {
+        this.title = title;
+        return this;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public Book setAuthor(String author) {
+        this.author = author;
+        return this;
+    }
+
+    public Publisher getPublisher() {
+        return publisher;
+    }
+
+    public Book setPublisher(Publisher publisher) {
+        this.publisher = publisher;
+        return this;
+    }
+
+    public double getCost() {
+        return cost;
+    }
+
+    public Book setCost(double cost) {
+        this.cost = cost;
+        return this;
+    }
+
+    public LocalDateTime getPublishDate() {
+        return publishDate;
+    }
+
+    public Book setPublishDate(LocalDateTime publishDate) {
+        this.publishDate = publishDate;
+        return this;
+    }
+
+    public Set<Book> getCompanionBooks() {
+        return companionBooks;
+    }
+
+    public Book addCompanionBooks(Book book) {
+        if (companionBooks != null)
+            this.companionBooks.add(book);
+        return this;
+    }
+
     @Override
     public String toString() {
         return "Book [isbn=" + isbn + ", title=" + title + ", author=" + author + ", publisher=" + publisher + ", cost=" + cost + "]";

persistence-modules/java-mongodb/src/test/java/com/baeldung/bsontojson/BsonToJsonIntegrationTest.java

@@ -0,0 +1,142 @@
+package com.baeldung.bsontojson;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.sql.Timestamp;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.Date;
+import java.util.TimeZone;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.bson.Document;
+import org.bson.json.Converter;
+import org.bson.json.JsonMode;
+import org.bson.json.JsonWriterSettings;
+import org.bson.json.StrictJsonWriter;
+import org.bson.types.ObjectId;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.jupiter.api.AfterEach;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.baeldung.morphia.domain.Book;
+import com.baeldung.morphia.domain.Publisher;
+import com.mongodb.MongoClient;
+import com.mongodb.client.MongoDatabase;
+
+import dev.morphia.Datastore;
+import dev.morphia.Morphia;
+
+public class BsonToJsonIntegrationTest {
+    
+    private static final String DB_NAME = "library";
+    private static Datastore datastore;
+
+    @BeforeClass
+    public static void setUp() {
+        Morphia morphia = new Morphia();
+        morphia.mapPackage("com.baeldung.morphia");
+        datastore = morphia.createDatastore(new MongoClient(), DB_NAME);
+        datastore.ensureIndexes();
+        
+        datastore.save(new Book()
+            .setIsbn("isbn")
+            .setTitle("title")
+            .setAuthor("author")
+            .setCost(3.95)
+            .setPublisher(new Publisher(new ObjectId("fffffffffffffffffffffffa"),"publisher"))
+            .setPublishDate(LocalDateTime.parse("2020-01-01T18:13:32Z", DateTimeFormatter.ISO_DATE_TIME))
+            .addCompanionBooks(new Book().setIsbn("isbn2")));
+    }
+    
+    @AfterClass
+    public static void tearDown() {
+        datastore.delete(datastore.createQuery(Book.class));
+    }
+
+    @Test
+    public void givenBsonDocument_whenUsingStandardJsonTransformation_thenJsonDateIsObjectEpochTime() {
+
+        String json = null;
+        try (MongoClient mongoClient = new MongoClient()) {
+            MongoDatabase mongoDatabase = mongoClient.getDatabase(DB_NAME);
+            Document bson = mongoDatabase.getCollection("Books").find().first();
+            json = bson.toJson();
+        }
+        
+        String expectedJson = "{\"_id\": \"isbn\", " + 
+            "\"className\": \"com.baeldung.morphia.domain.Book\", " + 
+            "\"title\": \"title\", " + 
+            "\"author\": \"author\", " + 
+            "\"publisher\": {\"_id\": {\"$oid\": \"fffffffffffffffffffffffa\"}, " + 
+            "\"name\": \"publisher\"}, " + 
+            "\"price\": 3.95, " + 
+            "\"publishDate\": {\"$date\": 1577898812000}}";
+
+        assertNotNull(json);
+        
+        assertEquals(expectedJson, json);
+    }
+    
+
+    @Test
+    public void givenBsonDocument_whenUsingRelaxedJsonTransformation_thenJsonDateIsObjectIsoDate() {
+   
+        String json = null;
+        try (MongoClient mongoClient = new MongoClient()) {
+            MongoDatabase mongoDatabase = mongoClient.getDatabase(DB_NAME);
+            Document bson = mongoDatabase.getCollection("Books").find().first();
+            json = bson.toJson(JsonWriterSettings
+                .builder()
+                .outputMode(JsonMode.RELAXED)
+                .build());
+        }
+        
+        String expectedJson = "{\"_id\": \"isbn\", " + 
+            "\"className\": \"com.baeldung.morphia.domain.Book\", " + 
+            "\"title\": \"title\", " + 
+            "\"author\": \"author\", " + 
+            "\"publisher\": {\"_id\": {\"$oid\": \"fffffffffffffffffffffffa\"}, " + 
+            "\"name\": \"publisher\"}, " + 
+            "\"price\": 3.95, " + 
+            "\"publishDate\": {\"$date\": \"2020-01-01T17:13:32Z\"}}";
+
+        assertNotNull(json);
+        
+        assertEquals(expectedJson, json);
+    }
+    
+    @Test
+    public void givenBsonDocument_whenUsingCustomJsonTransformation_thenJsonDateIsStringField() {
+
+        String json = null;
+        try (MongoClient mongoClient = new MongoClient()) {
+            MongoDatabase mongoDatabase = mongoClient.getDatabase(DB_NAME);
+            Document bson = mongoDatabase.getCollection("Books").find().first();
+            json = bson.toJson(JsonWriterSettings
+                .builder()
+                .dateTimeConverter(new JsonDateTimeConverter())
+                .build());
+        }
+
+        String expectedJson = "{\"_id\": \"isbn\", " + 
+            "\"className\": \"com.baeldung.morphia.domain.Book\", " + 
+            "\"title\": \"title\", " + 
+            "\"author\": \"author\", " + 
+            "\"publisher\": {\"_id\": {\"$oid\": \"fffffffffffffffffffffffa\"}, " + 
+            "\"name\": \"publisher\"}, " + 
+            "\"price\": 3.95, " + 
+            "\"publishDate\": \"2020-01-01T17:13:32Z\"}";
+
+        assertEquals(expectedJson, json);
+
+    }
+
+}

persistence-modules/java-mongodb/src/test/java/com/baeldung/bsontojson/JsonDateTimeConverter.java

@@ -0,0 +1,30 @@
+package com.baeldung.bsontojson;
+
+import java.time.Instant;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.Date;
+import java.util.TimeZone;
+
+import org.bson.json.Converter;
+import org.bson.json.StrictJsonWriter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class JsonDateTimeConverter implements Converter<Long> {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(JsonDateTimeConverter.class);
+    static final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ISO_INSTANT
+        .withZone(ZoneId.of("UTC"));
+
+    @Override
+    public void convert(Long value, StrictJsonWriter writer) {
+        try {
+            Instant instant = new Date(value).toInstant();
+            String s = DATE_TIME_FORMATTER.format(instant);
+            writer.writeString(s);
+        } catch (Exception e) {
+            LOGGER.error(String.format("Fail to convert offset %d to JSON date", value), e);
+        }
+    }
+}