1949-10-01 14:21:02    34c
1949-10-01 19:21:02    38c
1949-10-02 14:01:02    36c
1950-01-01 11:21:02    32c
1950-10-01 12:21:02    37c
1951-12-01 12:21:02    23c
1950-10-02 12:21:02    41c
1950-10-03 12:21:02    27c
1951-07-01 12:21:02    45c
1951-07-02 12:21:02    46c
1951-07-03 12:21:03    47c
1949-10-01 14:21:02    34c
1949-10-01 19:21:02    38c
1949-10-02 14:01:02    36c
1950-01-01 11:21:02    32c
1950-10-01 12:21:02    37c
1951-12-01 12:21:02    23c

package com.sjt.mr.tq.demo;import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;import org.apache.hadoop.io.WritableComparable;public class MyTQ implements WritableComparable<MyTQ>{private int year;//年private int month;//月private int day;//日private int wd;//温度public int getYear() {return year;}public void setYear(int year) {this.year = year;}public int getMonth() {return month;}public void setMonth(int month) {this.month = month;}public int getDay() {return day;}public void setDay(int day) {this.day = day;}public int getWd() {return wd;}public void setWd(int wd) {this.wd = wd;}@Overridepublic void write(DataOutput out) throws IOException {out.writeInt(year);out.writeInt(month);out.writeInt(day);out.writeInt(wd);}@Overridepublic void readFields(DataInput in) throws IOException {year = in.readInt();month = in.readInt();day = in.readInt();wd = in.readInt();}@Overridepublic int compareTo(MyTQ mytq) {//1980-05-02 34c//比较年是否相同int c1 = Integer.compare(year, mytq.getYear());if(c1==0){//如果相同则比较月份int c2 = Integer.compare(month, mytq.getMonth());if(c2==0){//如果月份相同则比较温度,使得温度降序排序return -Integer.compare(wd, mytq.getWd());}return c2;}return c1;}}

package com.sjt.mr.tq.demo;import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;public class MyMapper extends Mapper<Object, Text, MyTQ, IntWritable>{private MyTQ tqKey=new MyTQ();private IntWritable Tvalue=new IntWritable();//key记录的是偏移量，value为一行的数据
    @Override protected void map(Object key, Text value, Mapper<Object, Text, MyTQ, IntWritable>.Context context)throws IOException, InterruptedException {try {//1980-01-02 18:15:45    34c //根据制表符分割 获得 split[0]=1980-01-02 18:15:45 split[1]=34c String[] splits =value.toString().split("\t");//设值keySimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");Date date = sdf.parse(splits[0]);Calendar calendar = Calendar.getInstance();calendar.setTime(date);//给tqkey设值
            tqKey.setYear(calendar.get(calendar.YEAR));tqKey.setMonth(calendar.get(calendar.MONTH)+1);tqKey.setDay(calendar.get(calendar.DAY_OF_MONTH));int wd = Integer.parseInt(splits[1].substring(0, splits[1].length()-1));tqKey.setWd(wd);//设值温度
            Tvalue.set(wd);} catch (ParseException e) {// TODO Auto-generated catch block
            e.printStackTrace();}context.write(tqKey, Tvalue);}}

package com.sjt.mr.tq.demo;import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;
//分组比较
public class MyGroupComparator extends WritableComparator{//调用父类的构造方法public  MyGroupComparator(){super(MyTQ.class,true);}@Overridepublic int compare(WritableComparable a, WritableComparable b) {MyTQ tq1=(MyTQ)a;MyTQ tq2=(MyTQ)b;//先比较年 再比较月int c1 = Integer.compare(tq1.getYear(), tq2.getYear());if(c1==0){return Integer.compare(tq1.getMonth(), tq2.getMonth());}return c1;}
}

package com.sjt.mr.tq.demo;import java.io.IOException;import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;public class MyReduce extends Reducer<MyTQ, IntWritable,Text,IntWritable>{private Text key=new Text();private IntWritable value=new IntWritable();@Overrideprotected void reduce(MyTQ mytq, Iterable<IntWritable> values,Reducer<MyTQ, IntWritable, Text, IntWritable>.Context context) throws IOException, InterruptedException {int flag=0;//计数int day=0;//储存日期for (IntWritable v : values) {//如果计算为0取第一位的年月日:温度if(flag==0){//设key和value值key.set(mytq.getYear()+"-"+mytq.getMonth()+"-"+mytq.getDay()+":");value.set(mytq.getWd());//给day设值 防止重复天数day=mytq.getDay();flag++;//计数+1
                context.write(key, value);}//如果计数为1且日期不和第一次写出的日期不一致if(flag!=0&&mytq.getDay()!=day){key.set(mytq.getYear()+"-"+mytq.getMonth()+"-"+mytq.getDay()+":");value.set(mytq.getWd());context.write(key, value);break;}}}
}