Dissecting The Nutch Crawler -introduction

英文原文出处： DissectingTheNutchCrawler
转载本文请注明出处：http://blog.youkuaiyun.com/pwlazy

Introduction

The open-source Nutch search engine consists, very roughly, of three components:

• the crawler, which discovers and retrieves web pages

• theWebDB, a custom database that stores knownURLs and fetched page contents

• the indexer, which dissects pages and builds keyword-based indexes from them

This document attempts to describe the operation of the crawler. We begin with theory and drill down to into the details needed to create a customized crawler.

Nutch is implemented in Java, so basic knowledge of the language is assumed.

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介绍

开源Nutch搜索引擎大致包含3部分

• crawler，发觉和检索网页
• theWebDB，一个定制的数据库用于存储已知的url和检索的网页内容
  
• indexer，剖析页面以及从中构建基于关键词的索引

本文主要阐述了crawler的操作。我们从原理开始然后深挖到细节以至我们能定制crawler.

Nutch使用java实现的，所以我们假定你有基本的相关知识。

注：本人英文水平有限，翻译不当之处请批评指正，谢谢