データサイエンスにおけるJavaフレームワークの応用の展望

import org.apache.spark.SparkConf;
import org.apache.spark.SparkContext;
import org.apache.spark.sql.SQLContext;
import org.apache.spark.sql.Dataset;
import org.apache.spark.ml.feature.VectorAssembler;
import org.apache.spark.ml.classification.RandomForestClassifier;
import org.apache.spark.ml.evaluation.BinaryClassificationEvaluator;

// 创建 Spark 上下文和 SQL 上下文
SparkConf conf = new SparkConf().setMaster("local[*]").setAppName("Data Analysis with Spark");
SparkContext sc = new SparkContext(conf);
SQLContext sqlContext = new SQLContext(sc);

// 读取数据
Dataset<Row> df = sqlContext.read().csv("data.csv");

// 创建特征向量
VectorAssembler assembler = new VectorAssembler()
  .setInputCols(new String[]{"feature1", "feature2", "feature3"})
  .setOutputCol("features");
df = assembler.transform(df);

// 划分数据集为训练集和测试集
Dataset<Row>[] splits = df.randomSplit(new double[]{0.7, 0.3});
Dataset<Row> train = splits[0];
Dataset<Row> test = splits[1];

// 训练随机森林分类器
RandomForestClassifier classifier = new RandomForestClassifier()
  .setLabelCol("label")
  .setFeaturesCol("features");
RandomForestClassificationModel model = classifier.fit(train);

// 评估模型
BinaryClassificationEvaluator evaluator = new BinaryClassificationEvaluator()
  .setLabelCol("label")
  .setRawPredictionCol("prediction");
double accuracy = evaluator.evaluate(model.transform(test));

System.out.println("Accuracy: " + accuracy);