在linux下编写maven程序

1.在linux下安装eclipse-jee-kepler-SR2-linux-gtk.tar.gz

     并在桌面生成快捷方式

2.解压m2.tar.gz /root/

 

3.在maven程序/pom.xml添加引用，引用Hadoop，引用JDK

        <dependency>

            <groupId>org.apache.hadoop</groupId>

            <artifactId>hadoop-common</artifactId>

            <version>2.2.0</version>

        </dependency>

 

 

        <dependency>

            <groupId>org.apache.hadoop</groupId>

            <artifactId>hadoop-mapreduce-client-core</artifactId>

            <version>2.2.0</version>

        </dependency>

 

        <dependency>

            <groupId>jdk.tools</groupId>

            <artifactId>jdk.tools</artifactId>

            <version>1.7</version>

            <scope>system</scope>

            <systemPath>${JAVA_HOME}/lib/tools.jar</systemPath>

        </dependency>

4.编写DataCount，在这里，我们需要编写Map/Reduce两个阶段，一个负责读取数据并将有用的数据写入字节流中

     Map阶段：1.接收数据。2.传递数据

       public static class DCMapper extends Mapper<LongWritable, Text, Text, DataBean>

       {

              @Override

              protected void map(LongWritable key, Text value, Context context)

                           throws IOException, InterruptedException {

                     //1.jie shou shu ju

                     String line = value.toString();

                     String[] fields = line.split("\t");

                     String telNo = fields[1];

                     long up = Long.parseLong(fields[8]);

                     long down = Long.parseLong(fields[9]);

                     //2.chuan di shu ju

                     DataBean bean = new DataBean(telNo, up, down);

                     context.write(new Text(telNo), bean);

              }

       }

     Reduce阶段

 

       public static class DCReducer extends Reducer<Text, DataBean, Text, DataBean>

       {

              @Override

              protected void reduce(Text key, Iterable<DataBean> v2s,

                           Context context)

                           throws IOException, InterruptedException {

                     long up_sum = 0;

                     long down_sum = 0;

                     for (DataBean bean : v2s)

                     {

                           up_sum += bean.getUpPayLoad();

                           down_sum += bean.getDownPayLoad();

                     }

                     DataBean bean = new DataBean("", up_sum, down_sum);

                     context.write(key, bean);

              }

       }

5.Main方法，提供数据

       public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {

              Configuration conf = new Configuration();

              Job job = Job.getInstance(conf);

              

              job.setJarByClass(DataCount.class);

              job.setMapperClass(DCMapper.class);

              // k2 v2 and k3 v3

              // job.setMapOutputKeyClass(Text.class);

              // job.setMapOutputValueClass(DataBean.class);

              FileInputFormat.setInputPaths(job, new Path(args[0]));

              

              job.setReducerClass(DCReducer.class);

              job.setOutputKeyClass(Text.class);

              job.setOutputValueClass(DataBean.class);

              FileOutputFormat.setOutputPath(job, new Path(args[1]));

              job.waitForCompletion(true);

       }

 

6.将程序打包成jar包，并上传到hdfs中，hadoop fs -put HTTP_20130313143750.dat /data.doc

7.运行hadoop程序，hadoop jar /root/examples.jar cn.itcast.hadoop.mr.dc.DataCount /data.doc /dataout

 

 

说明，如果期间报错，注意检查yarn进程是否启动。如没有启动yarn，需要启动yarn