WordCount
准备 Maven，修改 Maven 的 settings.xml 配置，增加阿里云的仓库。
<mirror>
<id>aliyunmaven</id>
<mirrorOf>*</mirrorOf>
<name>阿里云公共仓库</name>
<url>https://maven.aliyun.com/repository/public</url>
</mirror>
1. 创建 Maven 项目导入 pom.xml 文件
安装 Maven 仓库管理工具，版本要求是 3.2 版本以上。新建 Maven 项目，配置 pom.xml。导入必要的包。
2. Spark-Scala 版本的 WordCount
val conf = new SparkConf()
conf.setMaster("local")
conf.setAppName("scala-wc")
val sc = new SparkContext(conf)
val lines = sc.textFile("./data/words")
val words = lines.flatMap(line=>{line.split(" ")})
val pairWords = words.map(word=>{new Tuple2(word,1)})
val result = pairWords.reduceByKey((v1:Int,v2:Int)=>{v1+v2})
result.foreach(println)
3. Spark-Java 版本的 WordCount
SparkConf conf = new SparkConf();
conf.setMaster("local");
conf.setAppName("java-wc");
JavaSparkContext sc = new JavaSparkContext(conf);
JavaRDD<String> lines = sc.textFile("./data/words");
JavaRDD<String> words = lines.flatMap(new
FlatMapFunction<String, String>() {
@Override
public Iterator<String> call(String s) throws Exception {
String[] split = s.split(" ");
return Arrays.asList(split).iterator();
}
});
JavaPairRDD<String, Integer> pairWords = words.mapToPair(new PairFunction<String, String, Integer>() {
@Override
public Tuple2<String, Integer> call(String word) throws Exception {
return new Tuple2<>(word, 1);
}
});
JavaPairRDD<String, Integer> result =pairWords.reduceByKey(new Function2<Integer, Integer,Integer>() {
@Override
public Integer call(Integer v1, Integer v2) throws Exception{
return v1 + v2;
}
});
result.foreach(new VoidFunction<Tuple2<String, Integer>>() {
@Override
public void call(Tuple2<String, Integer> tuple2) throws Exception {
System.out.println(tuple2);
}
});
sc.stop();
