Nutch-2.2.1----Nutch过滤URL实践
转载源地址：http://blog.csdn.net/skywalker_only/article/details/17848225
通过分析Nutch的配置文件Nutch-default.xml和阅读了部分源代码后，了解了Nutch的插件机制以及如何通过修改conf中的文件实现过滤抓取数据。默认情况下，实现URL过滤的类为RegexURLFilter，对应的过滤文件为regex-urlfilter.txt，在不修改该文件的情况下，Nutch可以过滤后缀以gif|GIF|jpg|JPG|png|PNG|ico|ICO|css|CSS|sit|SIT|eps|EPS|wmf|WMF|zip|ZIP|ppt|PPT|mpg|MPG|xls|XLS|gz|GZ|rpm|RPM|tgz|TGZ|mov|MOV|exe|EXE|jpeg|JPEG|bmp|BMP|js|JS结尾的文件，过滤包含?*!@=字符的URL，过滤/SameSomething/重复出现三次的URL，而接受其他一切URL。现在以http://hadoop.apache.com为抓取的URL为例，分为默认抓取和只抓取包含hadoop的URL两种情况。
先看第一种情况，即对rgex-urlfilter.txt不做任何修改，代码及结果如下所示。从结果可以看到，总共抓取了38条记录。
[hadoop@hadoop deploy]$ bin/crawl urls hadoop http://localhost:8983/solr/ 1
hbase(main):012:0> scan 'hadoop_webpage', {COLUMNS=>'f:ts'}
ROW COLUMN+CELL
com.apachecon.eu.www:http/c/aceu2009/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1D1
com.apachecon.us:http/c/acus2008/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1Ft
com.cafepress.www:http/hadoop/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1Fw
com.yahoo.developer:http/blogs/hadoop/2 column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV\x1D2
008/07/apache_hadoop_wins_terabyte_sort
_benchmark.html
org.apache.avro:http/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1Fw
org.apache.cassandra:http/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1Fx
org.apache.forrest:http/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV\x1F\xAC
org.apache.hadoop:http/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01C\xE1\xD1\xB2\xFC
org.apache.hadoop:http/bylaws.html column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1Fy
org.apache.hadoop:http/docs/current/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x06
org.apache.hadoop:http/docs/r0.23.10/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1Fy
org.apache.hadoop:http/docs/r1.2.1/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1Fz
org.apache.hadoop:http/docs/r2.1.1-beta column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x07
/
org.apache.hadoop:http/docs/r2.2.0/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F{
org.apache.hadoop:http/docs/stable/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x07
org.apache.hadoop:http/index.html column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F|
org.apache.hadoop:http/index.pdf column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x08
org.apache.hadoop:http/issue_tracking.h column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x08
tml
org.apache.hadoop:http/mailing_lists.ht column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x08
ml
org.apache.hadoop:http/privacy_policy.h column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x09
tml
org.apache.hadoop:http/releases.html column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F|
org.apache.hadoop:http/who.html column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F}
org.apache.hbase:http/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x09
org.apache.hive:http/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F~
org.apache.incubator:http/ambari/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F\x7F
org.apache.incubator:http/chukwa/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x09
org.apache.incubator:http/hama/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x0A
org.apache.mahout:http/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F\x7F
org.apache.pig:http/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F\x82
org.apache.wiki:http/hadoop column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x0A
org.apache.wiki:http/hadoop/PoweredBy column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x0A
org.apache.www:http/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x12
org.apache.www:http/foundation/sponsors column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F\x83
hip.html
org.apache.www:http/foundation/thanks.h column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x12
tml
org.apache.www:http/licenses/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F\x83
org.apache.zookeeper:http/ column=f:ts, timestamp=1388471264814, value=\x00\x00\x01CGV\x1F\x85
org.sortbenchmark:http/ column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x13
uk.co.guardian.www:http/technology/2011 column=f:ts, timestamp=1388471264808, value=\x00\x00\x01CGV%\x14
/mar/25/media-guardian-innovation-award
s-apache-hadoop
38 row(s) in 0.2590 seconds
[hadoop@hadoop deploy]$ bin/crawl urls hadoopWithFilter http://localhost:8983/solr/ 1
hbase(main):016:0> scan 'hadoopWithFilter_webpage',{COLUMNS=>'f:ts'}
ROW COLUMN+CELL
com.cafepress.www:http/hadoop/ column=f:ts, timestamp=1388473239724, value=\x00\x00\x01CGtGl
com.yahoo.developer:http/blogs/hadoop/2 column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtG\x88
008/07/apache_hadoop_wins_terabyte_sort
_benchmark.html
org.apache.hadoop:http/ column=f:ts, timestamp=1388473240778, value=\x00\x00\x01C\xE1\xF0\xEB\xCB
org.apache.hadoop:http/bylaws.html column=f:ts, timestamp=1388473239724, value=\x00\x00\x01CGtHv
org.apache.hadoop:http/docs/current/ column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xA7
org.apache.hadoop:http/docs/r0.23.10/ column=f:ts, timestamp=1388473239724, value=\x00\x00\x01CGtHw
org.apache.hadoop:http/docs/r1.2.1/ column=f:ts, timestamp=1388473239724, value=\x00\x00\x01CGtHw
org.apache.hadoop:http/docs/r2.1.1-beta column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xA8
/
org.apache.hadoop:http/docs/r2.2.0/ column=f:ts, timestamp=1388473239724, value=\x00\x00\x01CGtHx
org.apache.hadoop:http/docs/stable/ column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xA8
org.apache.hadoop:http/index.html column=f:ts, timestamp=1388473239724, value=\x00\x00\x01CGtHx
org.apache.hadoop:http/index.pdf column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xA8
org.apache.hadoop:http/issue_tracking.h column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xA9
tml
org.apache.hadoop:http/mailing_lists.ht column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xA9
ml
org.apache.hadoop:http/privacy_policy.h column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xA9
tml
org.apache.hadoop:http/releases.html column=f:ts, timestamp=1388473239724, value=\x00\x00\x01CGtHy
org.apache.hadoop:http/who.html column=f:ts, timestamp=1388473239724, value=\x00\x00\x01CGtHz
org.apache.wiki:http/hadoop column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xAA
org.apache.wiki:http/hadoop/PoweredBy column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xAA
uk.co.guardian.www:http/technology/2011 column=f:ts, timestamp=1388473240778, value=\x00\x00\x01CGtL\xAB
/mar/25/media-guardian-innovation-award
s-apache-hadoop
20 row(s) in 0.3090 seconds