Document Data Format: Extended JSON

Extended JSON Examples

The following examples show a document containing an ObjectId, date, and long number field represented in each Extended JSON format. Click the tab that corresponds to the format of the example you want to see:

Using the Document Classes

You can read an Extended JSON string into a Java document object by calling the parse() static method from either the Document or BsonDocument class, depending on which object type you need. This method parses the Extended JSON string in any of the formats and returns an instance of that class containing the data.

The following example shows how you can use the Document class to read an example Extended JSON string into a Document object using the parse() method:

String ejsonStr = "{ \"_id\": { \"$oid\": \"507f1f77bcf86cd799439011\"}," +
                  "\"myNumber\": {\"$numberLong\": \"4794261\" }}}";
Document doc = Document.parse(ejsonStr);
System.out.println(doc);

The output of the preceding code should look something like this:

Document{{_id=507f1f77bcf86cd799439011, myNumber=4794261}}

For more information, see our Fundamentals page on Documents.

Using the BSON Library

You can also read an Extended JSON string into Java objects without using the MongoDB Java driver's document classes by using the JsonReader class. This class contains methods to sequentially parse the fields and values in any format of the Extended JSON string, and returns them as Java objects. The driver's document classes also use this class to parse Extended JSON.

The following code example shows how you can use the JsonReader class to convert an Extended JSON string into Java objects:

String ejsonStr = "{ \"_id\": { \"$oid\": \"507f1f77bcf86cd799439011\"}," +
                  "\"myNumber\": {\"$numberLong\": \"4794261\" }}}";
JsonReader jsonReader = new JsonReader(ejsonStr);
jsonReader.readStartDocument();
jsonReader.readName("_id");
ObjectId id = jsonReader.readObjectId();
jsonReader.readName("myNumber");
Long myNumber = jsonReader.readInt64();
jsonReader.readEndDocument();
System.out.println(id + " is type: " + id.getClass().getName());
System.out.println(myNumber + " is type: " + myNumber.getClass().getName());
jsonReader.close();

The output of this code example should look something like this:

507f1f77bcf86cd799439011 is type: org.bson.types.ObjectId
4794261 is type: java.lang.Long

For more information, see the JsonReader API Documentation.

Using the Document Classes

You can write an Extended JSON string from an instance of Document or BsonDocument by calling the toJson() method, optionally passing it an instance of JsonWriterSettings to specify the Extended JSON format.

In this example, we output the Extended JSON in the Relaxed mode format.

Document myDoc = new Document();
myDoc.append("_id", new ObjectId("507f1f77bcf86cd799439012")).append("myNumber", 11223344);
JsonWriterSettings settings = JsonWriterSettings.builder().outputMode(JsonMode.RELAXED).build();
System.out.println(doc.toJson(settings));

The output of this code example should look something like this:

{"_id": {"$oid": "507f1f77bcf86cd799439012"}, "myNumber": 11223344}

Using the BSON Library

You can also output an Extended JSON string from data in Java objects using the BSON library with the JsonWriter class. To construct an instance of JsonWriter, pass a subclass of a Java Writer to specify how you want to output the Extended JSON. You can optionally pass a JsonWriterSettings instance to specify options such as the Extended JSON format. By default, the JsonWriter uses the Relaxed mode format. The MongoDB Java driver's document classes also use this class to convert BSON to Extended JSON.

The following code example shows how you can use JsonWriter to create an Extended JSON string and output it to System.out. We specify the format by passing the outputMode() builder method the JsonMode.EXTENDED constant:

JsonWriterSettings settings = JsonWriterSettings.builder().outputMode(JsonMode.EXTENDED).build();
try (JsonWriter jsonWriter = new JsonWriter(new BufferedWriter(new OutputStreamWriter(System.out)), settings)) {
    jsonWriter.writeStartDocument();
    jsonWriter.writeObjectId("_id", new ObjectId("507f1f77bcf86cd799439012"));
    jsonWriter.writeInt64("myNumber", 11223344);
    jsonWriter.writeEndDocument();
    jsonWriter.flush();
}

The output of this code example should look something like this:

{"_id": {"$oid": "507f1f77bcf86cd799439012"}, "myNumber": {"$numberLong": "11223344"}}

For more information about the methods and classes mentioned in this section, see the following API Documentation:

• JsonWriter

• JsonWriterSettings

• outputMode()