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Spark Connector Java Guide
Note
Source Code
For the source code that combines all of the Java examples, see JavaIntroduction.java.
Prerequisites
Basic working knowledge of MongoDB and Apache Spark. Refer to the MongoDB documentation, Spark documentation, and this MongoDB white paper for more details.
Running MongoDB instance (version 2.6 or later).
Spark 2.4.x.
Scala 2.12.x
Java 8 or later.
Getting Started
Dependency Management
Provide the Spark Core, Spark SQL, and MongoDB Spark Connector dependencies to your dependency management tool.
The following excerpt is from a Maven pom.xml
file:
<dependencies> <dependency> <groupId>org.mongodb.spark</groupId> <artifactId>mongo-spark-connector_2.12</artifactId> <version>3.0.2</version> </dependency> <dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-core_2.12</artifactId> <version>3.0.2</version> </dependency> <dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-sql_2.12</artifactId> <version>3.0.2</version> </dependency> </dependencies>
Configuration
For the configuration classes, use the Java-friendly create
methods
instead of the native Scala apply
methods.
The Java API provides a JavaSparkContext
that takes a
SparkContext
object from the SparkSession
.
When specifying the Connector configuration via SparkSession
, you
must prefix the settings appropriately. For details and other
available MongoDB Spark Connector options, see the
Configuration Options.
package com.mongodb.spark_examples; import org.apache.spark.api.java.JavaSparkContext; import org.apache.spark.sql.SparkSession; public final class GettingStarted { public static void main(final String[] args) throws InterruptedException { /* Create the SparkSession. * If config arguments are passed from the command line using --conf, * parse args for the values to set. */ SparkSession spark = SparkSession.builder() .master("local") .appName("MongoSparkConnectorIntro") .config("spark.mongodb.input.uri", "mongodb://127.0.0.1/test.myCollection") .config("spark.mongodb.output.uri", "mongodb://127.0.0.1/test.myCollection") .getOrCreate(); // Create a JavaSparkContext using the SparkSession's SparkContext object JavaSparkContext jsc = new JavaSparkContext(spark.sparkContext()); // More application logic would go here... jsc.close(); } }
The spark.mongodb.input.uri specifies the MongoDB server address(
127.0.0.1
), the database to connect (test
), and the collection (myCollection
) from which to read data, and the read preference.The spark.mongodb.output.uri specifies the MongoDB server address(
127.0.0.1
), the database to connect (test
), and the collection (myCollection
) to which to write data.
You can use a SparkSession
object to write data to MongoDB, read
data from MongoDB, create Datasets, and perform SQL operations.
MongoSpark
Helper
To facilitate interaction between MongoDB and Spark, the MongoDB Spark
Connector provides the com.mongodb.spark.api.java.MongoSpark
helper.