Nutch 1.3 学习笔记2

1. Nutch 1.3 运行命令的一些介绍

要看Nutch的命令说明，可执行如下命令bin/nutch

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Usage: nutch [-core] COMMAND

where COMMAND is one of:

crawl one-step crawler for intranets

readdb read / dump crawl db

convdb convert crawl db from pre-0.9 format

mergedb merge crawldb-s, with optional filtering

readlinkdb read / dump link db

inject inject new urls into the database

generate generate new segments to fetch from crawl db

freegen generate new segments to fetch from text files

fetch fetch a segment's pages

parse parse a segment's pages

readseg read / dump segment data

mergesegs merge several segments, with optional filtering and slicing

updatedb update crawl db from segments after fetching

invertlinks create a linkdb from parsed segments

mergelinkdb merge linkdb-s, with optional filtering

solrindex run the solr indexer on parsed segments and linkdb

solrdedup remove duplicates from solr

solrclean remove HTTP 301 and 404 documents from solr

plugin load a plugin and run one of its classes main()

or

CLASSNAME run the class named CLASSNAME

Most commands print help when invoked w/o parameters.

Expert: -core option is for developers only. It avoids building the job jar,

instead it simply includes classes compiled with ant compile-core.

NOTE: this works only for jobs executed in 'local' mode

2. 单个命令的说明

2.1 bin/nutch crawl

Usage: Crawl <urlDir> -solr <solrURL> [-dir d] [-threads n] [-depth i] [-topN N]

这是用于对urls进行一键式抓取的命令

2.2 bin/nutch readdb

Usage: CrawlDbReader <crawldb> (-stats | -dump <out_dir> | -topN <nnnn> <out_dir> [<min>] | -url <url>)

这是用于对crawldb数据库进行读取的命令，主要是用于dump相应的url文件

2.3 bin/nutch convdb

这个命令主要用于把nutch 0.9的crawldb数据转换成1.3的格式

2.4 bin/nutch mergedb

Usage: CrawlDbMerger <output_crawldb> <crawldb1> [<crawldb2> <crawldb3> ...] [-normalize] [-filter]

这个命令主要用于合并多个crawldb数据库

2.5 bin/nutch readlinkdb

Usage: LinkDbReader <linkdb> {-dump <out_dir> | -url <url>)

主要用于读取invertlinks产生的链接数据

2.6 bin/nutch inject

Usage: Injector <crawldb> <url_dir>

主要用于把url_dir中的url注入到crawldb数据库中去

2.7 bin/nutch generate

Usage: Generator <crawldb> <segments_dir> [-force] [-topN N] [-numFetchers numFetchers] [-adddays numDays] [-noFilter] [-noNorm][-maxNumSegments num]

用于产生准备抓取的url列表

2.8 bin/nutch freegen

Usage: FreeGenerator <inputDir> <segmentsDir> [-filter] [-normalize]

从文本文件中提取urls来产生新的抓取segment

2.9 bin/nutch fetch

Usage: Fetcher <segment> [-threads n] [-noParsing]

主要用来对generate产生的urls进行抓取，这里用到了Hadoop架构，使用了一个FetcherOutputFormat来对其结果进行多目录输出

2.10 bin/nutch parse

Usage: ParseSegment segment

主要是对抓取的内容进行分析

2.11 bin/nutch readseg

Usage: SegmentReader (-dump ... | -list ... | -get ...) [general options]

这个命令主要是输出segment的内容

2.12 bin/nutch invertlinks

Usage: LinkDb <linkdb> (-dir <segmentsDir> | <seg1> <seg2> ...) [-force] [-noNormalize] [-noFilter]

这个命令主要是得到抓取内容的外链接数据

2.13 bin/nutch solrindex

Usage: SolrIndexer <solr url> <crawldb> <linkdb> (<segment> ... | -dir <segments>)

对抓以的内容进行索引建立，前提是要有solr环境。

2.14 bin/nutch plugin

Usage: PluginRepository pluginId className [arg1 arg2 ...]

这个命令主要对插件进行测试，运行其main方法