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Hadoop MapReduce应用案例

Hadoop MapReduce应用案例

作者: Yohann丶blog | 来源:发表于2021-05-23 21:52 被阅读0次
    1141621777867_.pic.jpg

    环境

    • CentOS 6.8 64位 1核 2GB

    • JDK 1.7.0_55 64 位

    • Hadoop 1.1.2

    准备测试数据

    • 创建部门文件 dept，内容如下
    10,DEVELOP,BEIJING
20,UI,SHANGHAI
30,TEST,GUANGZHOU
40,OPS,SHENZHEN
    • 创建员工文件 emp，内容如下
    7369,SMITH,PRIMARY,7902,17-12月-80,10500,,20
7499,ALLEN,SENIOR,7698,20-2月-81,15500,300,30
7521,WARD,SENIOR,7698,22-2月-81,17500,500,30
7566,JONES,MANAGER,7839,02-4月-81,20500,,20
7654,MARTIN,SENIOR,7698,28-9月-81,16500,1400,30
7698,BLAKE,MANAGER,7839,01-5月-81,21000,,30
7782,CLARK,MANAGER,7839,09-6月-81,20000,,10
7839,KING,SENIOR,,17-11月-81,14500,,10
7844,TURNER,SENIOR,7698,08-9月-81,19500,0,30
7900,JAMES,PRIMARY,7698,03-12月-81,10000,,30
7902,FORD,SENIOR,7566,03-12月-81,19000,,20
7934,MILLER,PRIMARY,7782,23-1月-82,9500,,10
    • 在 HDFS 创建 /class6/input 目录
    $ hadoop fs -mkdir -p /class6/input
    • 把 dept、emp 上传到 HDFS 中 /class6/input 目录中
    $ hadoop fs -copyFromLocal dept /class6/input
$ hadoop fs -copyFromLocal emp /class6/input
    • 在HDFS中查看 /class6/input 目录
    $ hadoop fs -ls /class6/input
Found 2 items
-rw-r--r--   1 yohann supergroup         80 2021-05-15 22:39 /class6/input/dept
-rw-r--r--   1 yohann supergroup        538 2021-05-15 22:39 /class6/input/emp
    • 创建 /app/hadoop-1.1.2/myclass/class6 目录并进入
    $ cd /app/hadoop-1.1.2/myclass
$ mkdir class6
$ cd class6

    求各个部门的总工资

    • 创建 Q1SumDeptSalary.java，代码如下
    import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.filecache.DistributedCache;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
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.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class Q1SumDeptSalary extends Configured implements Tool {

    public static class MapClass extends Mapper<LongWritable, Text, Text, Text> {

        private Map<String, String> deptMap = new HashMap<String, String>();
        private String[] kv;

        @Override
        protected void setup(Context context) throws IOException, InterruptedException {
            BufferedReader in = null;
            try {

                Path[] paths = DistributedCache.getLocalCacheFiles(context.getConfiguration());
                String deptIdName = null;
                for (Path path : paths) {

                    if (path.toString().contains("dept")) {
                        in = new BufferedReader(new FileReader(path.toString()));
                        while (null != (deptIdName = in.readLine())) {
                            
                            deptMap.put(deptIdName.split(",")[0], deptIdName.split(",")[1]);
                        }
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    if (in != null) {
                        in.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {

            kv = value.toString().split(",");

            if (deptMap.containsKey(kv[7])) {
                if (null != kv[5] && !"".equals(kv[5].toString())) {
                    context.write(new Text(deptMap.get(kv[7].trim())), new Text(kv[5].trim()));
                }
            }
        }
    }

    public static class Reduce extends Reducer<Text, Text, Text, LongWritable> {

        public void reduce(Text key, Iterable<Text> values, Context context) throws IOException, InterruptedException {

            long sumSalary = 0;
            for (Text val : values) {
                sumSalary += Long.parseLong(val.toString());
            }

            context.write(key, new LongWritable(sumSalary));
        }
    }

    @Override
    public int run(String[] args) throws Exception {

        Job job = new Job(getConf(), "Q1SumDeptSalary");
        job.setJobName("Q1SumDeptSalary");
        job.setJarByClass(Q1SumDeptSalary.class);
        job.setMapperClass(MapClass.class);
        job.setReducerClass(Reduce.class);

        job.setInputFormatClass(TextInputFormat.class);

        job.setOutputFormatClass(TextOutputFormat.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);

        String[] otherArgs = new GenericOptionsParser(job.getConfiguration(), args).getRemainingArgs();
        DistributedCache.addCacheFile(new Path(otherArgs[0]).toUri(), job.getConfiguration());
        FileInputFormat.addInputPath(job, new Path(otherArgs[1]));
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[2]));

        job.waitForCompletion(true);
        return job.isSuccessful() ? 0 : 1;
    }

    public static void main(String[] args) throws Exception {
        int res = ToolRunner.run(new Configuration(), new Q1SumDeptSalary(), args);
        System.exit(res);
    }
}
    • 编译打包
    $ javac -classpath ../../hadoop-core-1.1.2.jar:../../lib/commons-cli-1.2.jar Q1SumDeptSalary.java
$ jar cvf ./Q1SumDeptSalary.jar ./Q1SumDept*.class
$ mv *.jar /app/hadoop-1.1.2/
$ rm Q1SumDept*.class
    • 测试
    $ hadoop jar Q1SumDeptSalary.jar Q1SumDeptSalary hdfs://hadoop:9000/class6/input/dept hdfs://hadoop:9000/class6/input/emp hdfs://hadoop:9000/class6/out1
$ hadoop fs -cat /class6/out1/part-r-00000
DEVELOP 44000
TEST    100000
UI  50000

    求各个部门的人数和平均工资

    • 创建 Q2DeptNumberAveSalary.java，代码如下
    import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.filecache.DistributedCache;
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.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class Q2DeptNumberAveSalary extends Configured implements Tool {

    public static class MapClass extends Mapper<LongWritable, Text, Text, Text> {

        private Map<String, String> deptMap = new HashMap<String, String>();
        private String[] kv;

        @Override
        protected void setup(Context context) throws IOException, InterruptedException {
            BufferedReader in = null;
            try {
                Path[] paths = DistributedCache.getLocalCacheFiles(context.getConfiguration());
                String deptIdName = null;
                for (Path path : paths) {

                    if (path.toString().contains("dept")) {
                        in = new BufferedReader(new FileReader(path.toString()));
                        while (null != (deptIdName = in.readLine())) {
                            
                            deptMap.put(deptIdName.split(",")[0], deptIdName.split(",")[1]);
                        }
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    if (in != null) {
                        in.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {

            kv = value.toString().split(",");

            if (deptMap.containsKey(kv[7])) {
                if (null != kv[5] && !"".equals(kv[5].toString())) {
                    context.write(new Text(deptMap.get(kv[7].trim())), new Text(kv[5].trim()));
                }
            }
        }
    }

    public static class Reduce extends Reducer<Text, Text, Text, Text> {

        public void reduce(Text key, Iterable<Text> values, Context context) throws IOException, InterruptedException {

            long sumSalary = 0;
            int deptNumber = 0;

            for (Text val : values) {
                sumSalary += Long.parseLong(val.toString());
                deptNumber++;
            }

            context.write(key, new Text("Dept Number:" + deptNumber + ", Ave Salary:" + sumSalary / deptNumber));
        }
    }

    @Override
    public int run(String[] args) throws Exception {

        Job job = new Job(getConf(), "Q2DeptNumberAveSalary");
        job.setJobName("Q2DeptNumberAveSalary");
        job.setJarByClass(Q2DeptNumberAveSalary.class);
        job.setMapperClass(MapClass.class);
        job.setReducerClass(Reduce.class);

        job.setInputFormatClass(TextInputFormat.class);

        job.setOutputFormatClass(TextOutputFormat.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);

        String[] otherArgs = new GenericOptionsParser(job.getConfiguration(), args).getRemainingArgs();
        DistributedCache.addCacheFile(new Path(otherArgs[0]).toUri(), job.getConfiguration());
        FileInputFormat.addInputPath(job, new Path(otherArgs[1]));
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[2]));

        job.waitForCompletion(true);
        return job.isSuccessful() ? 0 : 1;
    }

    public static void main(String[] args) throws Exception {
        int res = ToolRunner.run(new Configuration(), new Q2DeptNumberAveSalary(), args);
        System.exit(res);
    }
}
    • 编译打包
    $ javac -classpath ../../hadoop-core-1.1.2.jar:../../lib/commons-cli-1.2.jar Q2DeptNumberAveSalary.java
$ jar cvf ./Q2DeptNumberAveSalary.jar ./Q2DeptNum*.class
$ mv *.jar /app/hadoop-1.1.2/
$ rm Q2DeptNum*.class
    • 测试
    $ hadoop jar Q2DeptNumberAveSalary.jar Q2DeptNumberAveSalary hdfs://hadoop:9000/class6/input/dept hdfs://hadoop:9000/class6/input/emp hdfs://hadoop:9000/class6/out2
$ hadoop fs -cat /class6/out2/part-r-00000
DEVELOP Dept Number:3, Ave Salary:14666
TEST    Dept Number:6, Ave Salary:16666
UI  Dept Number:3, Ave Salary:16666

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