1.编写map函数，reduce函数

（1）创建mapper.py文件

cd /home/hadoop/wc 

gedit mapper.p

 

（2）mapper函数

 

#!/usr/bin/env pythonimport sysfor i in stdin:    i = i.strip()    words = i.split()    for word in words:    print '%s\t%s' % (word,1) （3）reducer.py文件创建

cd /home/hadoop/wc

gedit reducer.py

（4）reducer函数

#!/usr/bin/env pythonfrom operator import itemgetterimport syscurrent_word = Nonecurrent_count = 0word = Nonefor i in stdin:    i = i.strip()    word, count = i.split('\t',1)    try:    count = int(count)    except ValueError:    continue    if current_word == word:    current_count += count     else:    if current_word:        print '%s\t%s' % (current_word, current_count)    current_count = count    current_word = wordif current_word == word:    print '%s\t%s' % (current_word, current_count) 2.将其权限作出相应修改

chmod a+x /home/hadoop/mapper.py

echo "foo foo quux labs foo bar quux" | /home/hadoop/wc/mapper.py

echo "foo foo quux labs foo bar quux" | /home/hadoop/wc/mapper.py | sort -k1,1 | /home/hadoop/wc/reducer.p 3.本机上测试运行代码

放到HDFS上运行

下载并上传文件到hdfs上

cd  /home/hadoop/wcwget http://www.gutenber.org/files/5000/5000-8.txtwget http://www.gutenber.org/cache/epub/20417/pg20417.txt

cd /usr/hadoop/wchdfs dfs -put /home/hadoop/hadoop/gutenberg/*.txt /user/hadoop/input