Java Example Code

Development Description

Mongo can be connected only through enhanced datasource connections.

Note

DDS is compatible with the MongoDB protocol.

  • Prerequisites

    An enhanced datasource connection has been created on the DLI management console and bound to a queue in packages.

    Note

    Hard-coded or plaintext passwords pose significant security risks. To ensure security, encrypt your passwords, store them in configuration files or environment variables, and decrypt them when needed.

  • Code implementation

    1. Import dependencies.

      • Maven dependency involved

        <dependency>
  <groupId>org.apache.spark</groupId>
  <artifactId>spark-sql_2.11</artifactId>
  <version>2.3.2</version>
</dependency>

      • Import dependency packages.

        import org.apache.spark.SparkConf;
import org.apache.spark.SparkContext;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.SQLContext;
import org.apache.spark.sql.SaveMode;

    2. Create a session.

      SparkContext sparkContext = new SparkContext(new SparkConf().setAppName("datasource-mongo"));
JavaSparkContext javaSparkContext = new JavaSparkContext(sparkContext);
SQLContext sqlContext = new SQLContext(javaSparkContext);

  • Connecting to data sources through DataFrame APIs

    1. Read JSON data as DataFrames.

      JavaRDD<String> javaRDD = javaSparkContext.parallelize(Arrays.asList("{\"id\":\"5\",\"name\":\"Ann\",\"age\":\"23\"}"));
Dataset<Row> dataFrame = sqlContext.read().json(javaRDD);

    2. Set connection parameters.

      String url = "192.168.4.62:8635,192.168.5.134:8635/test?authSource=admin";
String uri = "mongodb://username:pwd@host:8635/db";
String user = "rwuser";
String database = "test";
String collection = "test";
String password = "######";

      Note

      For details about the parameters, see Table 1.

    3. Import data to Mongo.

      dataFrame.write().format("mongo")
     .option("url",url)
     .option("uri",uri)
     .option("database",database)
     .option("collection",collection)
     .option("user",user)
     .option("password",password)
     .mode(SaveMode.Overwrite)
     .save();

    4. Read data from Mongo.

      sqlContext.read().format("mongo")
    .option("url",url)
    .option("uri",uri)
    .option("database",database)
    .option("collection",collection)
    .option("user",user)
    .option("password",password)
    .load().show();

  • Submitting a Spark job

    1. Upload the Java code file to DLI.

    2. In the Spark job editor, select the corresponding dependency module and execute the Spark job.

      Note

      • If the Spark version is 2.3.2 (will be offline soon) or 2.4.5, specify the Module to sys.datasource.mongo when you submit a job.

      • If the Spark version is 3.1.1, you do not need to select a module. Configure Spark parameters (--conf).

        spark.driver.extraClassPath=/usr/share/extension/dli/spark-jar/datasource/mongo/*

        spark.executor.extraClassPath=/usr/share/extension/dli/spark-jar/datasource/mongo/*

Complete Example Code

import org.apache.spark.SparkConf;
import org.apache.spark.SparkContext;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.SQLContext;
import org.apache.spark.sql.SaveMode;
import java.util.Arrays;

public class TestMongoSparkSql {
  public static void main(String[] args) {
    SparkContext sparkContext = new SparkContext(new SparkConf().setAppName("datasource-mongo"));
    JavaSparkContext javaSparkContext = new JavaSparkContext(sparkContext);
    SQLContext sqlContext = new SQLContext(javaSparkContext);

//    // Read json file as DataFrame, read csv / parquet file, same as json file distribution
//    DataFrame dataFrame = sqlContext.read().format("json").load("filepath");

    // Read RDD in JSON format to create DataFrame
    JavaRDD<String> javaRDD = javaSparkContext.parallelize(Arrays.asList("{\"id\":\"5\",\"name\":\"Ann\",\"age\":\"23\"}"));
    Dataset<Row> dataFrame = sqlContext.read().json(javaRDD);

    String url = "192.168.4.62:8635,192.168.5.134:8635/test?authSource=admin";
    String uri = "mongodb://username:pwd@host:8635/db";
    String user = "rwuser";
    String database = "test";
    String collection = "test";
    String password = "######";

    dataFrame.write().format("mongo")
            .option("url",url)
            .option("uri",uri)
            .option("database",database)
            .option("collection",collection)
            .option("user",user)
            .option("password",password)
            .mode(SaveMode.Overwrite)
            .save();

    sqlContext.read().format("mongo")
            .option("url",url)
            .option("uri",uri)
            .option("database",database)
            .option("collection",collection)
            .option("user",user)
            .option("password",password)
            .load().show();
    sparkContext.stop();
    javaSparkContext.close();
  }
}
last updated: 2024-09-09 13:20 UTC - commit: 65895976c96395f85134486700243c896ed0913e