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Spark Mongodb连接器Scala-缺少数据库名称

apache-spark-sql apache-spark scala mongodb

8

Daniil Andreyevich Baunov · 技术社区 · 8 年前

我遇到了一个奇怪的问题。我正在尝试使用MongoDB Spark连接器将Spark本地连接到MongoDB。

val readConfig = ReadConfig(Map("uri" -> "mongodb://localhost:27017/movie_db.movie_ratings", "readPreference.name" -> "secondaryPreferred"), Some(ReadConfig(sc)))
val writeConfig = WriteConfig(Map("uri" -> "mongodb://127.0.0.1/movie_db.movie_ratings"))

// Load the movie rating data from Mongo DB
val movieRatings = MongoSpark.load(sc, readConfig).toDF()

movieRatings.show(100)

java.lang.IllegalArgumentException: Missing database name. Set via the 'spark.mongodb.input.uri' or 'spark.mongodb.input.database' property.

在线设置readConfig。我不明白为什么它抱怨我在地图中有一个uri属性,却没有设置uri。我可能错过了什么。

2 回复 | 直到 8 年前

1

11

mrsrinivas 8 年前

你可以从 SparkSession

val spark = SparkSession.builder()
    .master("local")
    .appName("MongoSparkConnectorIntro")
    .config("spark.mongodb.input.uri", "mongodb://localhost:27017/movie_db.movie_ratings")
    .config("spark.mongodb.input.readPreference.name", "secondaryPreferred")
    .config("spark.mongodb.output.uri", "mongodb://127.0.0.1/movie_db.movie_ratings")
    .getOrCreate()

使用配置创建数据帧

val readConfig = ReadConfig(Map("uri" -> "mongodb://localhost:27017/movie_db.movie_ratings", "readPreference.name" -> "secondaryPreferred"))
val df = MongoSpark.load(spark)

将df写入mongodb

MongoSpark.save(
df.write
    .option("spark.mongodb.output.uri", "mongodb://127.0.0.1/movie_db.movie_ratings")
    .mode("overwrite"))

在您的代码中:

val readConfig = ReadConfig(Map(
    "spark.mongodb.input.uri" -> "mongodb://localhost:27017/movie_db.movie_ratings", 
    "spark.mongodb.input.readPreference.name" -> "secondaryPreferred"), 
    Some(ReadConfig(sc)))

val writeConfig = WriteConfig(Map(
    "spark.mongodb.output.uri" -> "mongodb://127.0.0.1/movie_db.movie_ratings"))

2

1

Vignesh Jaganathan 7 年前

SparkSession sparkSession = SparkSession.builder()
    .master("local")
    .appName("MongoSparkConnector")
    .config("spark.mongodb.input.uri","mongodb://localhost:27017/movie_db.movie_ratings")
    .config("spark.mongodb.input.readPreference.name", "secondaryPreferred")
    .config("spark.mongodb.output.uri", "mongodb://127.0.0.1/movie_db.movie_ratings")
    .getOrCreate()

 SparkSession sparkSession = SparkSession.builder()
        .master("local")
        .appName("MongoSparkConnector")
        .getOrCreate()

然后

     String mongoUrl = "mongodb://localhost:27017/movie_db.movie_ratings";
   sparkSession.sparkContext().conf().set("spark.mongodb.input.uri", mongoURL);
   sparkSession.sparkContext().conf().set("spark.mongodb.output.uri", mongoURL);
   Map<String, String> readOverrides = new HashMap<String, String>();
   readOverrides.put("collection", sourceCollection);
   readOverrides.put("readPreference.name", "secondaryPreferred");
   ReadConfig readConfig = ReadConfig.create(sparkSession).withOptions(readOverrides);
   Dataset<Row> df = MongoSpark.loadAndInferSchema(sparkSession,readConfig);