java wordcount

import com.google.common.base.Splitter;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.FlatMapFunction;
import org.apache.spark.api.java.function.Function2;
import org.apache.spark.api.java.function.PairFunction;
import org.apache.spark.api.java.function.VoidFunction;
import scala.Tuple2;
 
import java.util.Arrays;
import java.util.Iterator;
 
public class WordCount {
    public static void main(String[] args) {
        SparkConf sparkConf = new SparkConf().setAppName("WordCount").setMaster("local");
        JavaSparkContext sc = new JavaSparkContext(sparkConf);
        JavaRDD<String> lines = sc.textFile("file:/Users/zhudechao/gitee/bigdata/xzdream_spark/input/a.txt");
        JavaRDD<String> words = lines.flatMap(new FlatMapFunction<String, String>() {
 
            @Override
            public Iterator<String> call(String line) throws Exception {
                return Arrays.asList(line.split(" ")).iterator();
            }
        });
 
        JavaPairRDD<String,Integer> pairRDD = words.mapToPair(new PairFunction<String, String, Integer>() {
            @Override
            public Tuple2<String, Integer> call(String word) throws Exception {
                return new Tuple2<String, Integer>(word,1);
            }
        });
 
        JavaPairRDD<String,Integer> wordCounts = pairRDD.reduceByKey(new Function2<Integer, Integer, Integer>() {
            @Override
            public Integer call(Integer v1, Integer v2) throws Exception {
                return v1 + v2;
            }
        });
 
        wordCounts.foreach(new VoidFunction<Tuple2<String, Integer>>() {
            @Override
            public void call(Tuple2<String, Integer> wordcount) throws Exception {
                System.out.println(wordcount._1 + ":"+wordcount._2);
            }
        });
    }
}

package com.huawei.mapreduce.wordcount;

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

public class WordCountApp {
    public static class MyMapper extends Mapper<LongWritable, Text, Text, LongWritable>{
        @Override
        protected void map(LongWritable key, Text value, Mapper<LongWritable, Text, Text, LongWritable>.Context context) throws IOException, InterruptedException {
            String line = value.toString();
            String[] splited = line.split("\t");
            for (String word : splited) {
                Text k2 = new Text(word);
                LongWritable v2 = new LongWritable(1);
                context.write(k2, v2);
            }
        }
    }

    public static class MyReducer extends Reducer<Text, LongWritable, Text, LongWritable>{
        @Override
        protected void reduce(Text k2, Iterable<LongWritable> v2s,
                              Reducer<Text, LongWritable, Text, LongWritable>.Context context) throws IOException, InterruptedException {
            long count = 0L;
            for (LongWritable times : v2s) {
                count += times.get();
            }
            LongWritable v3 = new LongWritable(count);
            context.write(k2, v3);
        }
    }

    public static void main(String[] args) throws Exception{
        Configuration conf = new Configuration();
        Job job = Job.getInstance(conf , WordCountApp.class.getSimpleName());
        //必須指定
        job.setJarByClass(WordCountApp.class);

        //指定本業務job要使用的Mapper業務類
        job.setMapperClass(MyMapper.class);
        //指定mapper輸出資料的<k2,v2>的型別
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(LongWritable.class);

        //指定本業務job要使用的Reducer業務類
        job.setReducerClass(MyReducer.class);
        //指定reducer輸出資料的<k3,v3>的型別
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(LongWritable.class);

        //輸入資料來自哪里
        FileInputFormat.setInputPaths(job, new Path(args[0]));
        //輸出資料寫到哪里
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        //true表示將運行進度等資訊及時輸出給用戶
        boolean res = job.waitForCompletion(true);
        System.exit(res?0:1);
    }
}

tar -zxvf jdk-8u341-linux-x64.tar.gz

wget https://hcip-materials.obs.cn-north-4.myhuaweicloud.com/jdk-8u341-linux-x64.tar.gz

scp ~/eclipse-workspace/HDFSAPI/target/HDFSAPI-jar-with-dependencies.jar [email protected]:/root

ssh root@xxx.xxx.xxx.xxx

yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.IsFile
yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.CreateFile1
yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.IsFile
yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.CreateFile1
yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.CreateFile2
yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.ScanFile /user/test/hdfs/file10.txt
yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.ScanFile /user/test/hdfs/file11.txt
yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.DeleteFile /user/test/hdfs/file10.txt
yarn jar HDFSAPI-jar-with-dependencies.jar com.huawei.hdfs.IsFile

yarn jar MRAPI-jar-with-dependencies.jar com.huawei.mapreduce.wordcount.WordCountApp /user/user1/MR_data /user/user1/MR_out

hdfs dfs -mkdir /user/user1
hdfs dfs -put MR_data /user/user1/

hdfs dfs -ls /user/user1/MR_out/
hdfs dfs -cat /user/user1/MR_out/part-r-00000

hdfs dfs -mkdir -p /user/user1/MR/input
hdfs dfs -mkdir -p /user/user1/MR/output

hdfs dfs -put mrsort.txt /user/user1/MR/input
hdfs dfs -ls /user/user1/MR/output
hdfs dfs -cat /user/user1/MR/output/part-r-00000
hdfs dfs -cat /user/user1/MR/output/part-r-00001
hdfs dfs -cat /user/user1/MR/output/part-r-00002

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