MapReduce 例子

目的：
统计手机号在某个时间段的流量
流量分上行流量和下行流量

jar包依赖

<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>

代码

public class DataCount{    public static  void main(String[] args) throws IOException{        Configuration conf = new Configuration();        //conf.set();        Job job = Job.getInstance(conf);        job.setJarByClass(DataCount.class);        Job.setMappperClass(DcMapper.class);        job.setMapOutputKeyValueClass(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]));    }    public static class DcMapper extends Mapper<LongWritable,Text,Text,DataBean>{        protected void map(LongWritable key,Text value,Context context) throws IOException,InterruptedException{            String line = value.toString;            Stirng[] fields = line.split("\t");            String telNo=fields[1];//根据文件中的位置确定            long upPayLoad=Long.parseLong(fields[3]);            long downPayLoad=Long.parseLong(fields[4]);            DataBean bean=new DataBean(telNo,up,down);            context.write(new Text(telNo),bean);        }    }    public static class DcRducer extends Reducer<Text,DataBean,Text,DataBean>{        protected void reduce(Text key,Iterable<DataBean> v2s,Context context){            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);        }    }}public class DataBean implements Writable{    private String telNo;    private long upPayLoad;    private long downPayLoad;    private long totalPayLoad;    public DataBean(){    }    public DataBean(String telNo,long upPayLoad,long downPayLoad){        this.telNo=telNo;        this.upPayLoad=upPayLoad;        this.downPayLoad=downPayLoad;        this.totalPayLoad=upPayLoad+downPayLoad;    }    //serialize    public void write(DataOutput out) throws IOException{        out.writeUTF(telNo);        out.writeLong(upPayLoad);        out.writeLong(downPayLoad);        out.writeLong(totalPayLoad);    }    //deserialize    public void readFields(DataInput in) throws IOException{        this.telNo=in.readUTF();        this.upPayLoad=in.readLong(upPayLoad);        this.downPayLoad=in.readLong(downPayLoad);        this.totalPayLoad=in.readLong(totalPayLoad);    }    public String toString(){        return this.upPayLoad+"\t"+this.downPayLoad+"\t"+this.totalPayLoad;    }    getter\setter}