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leibnitz:
你好,为什么在全网抓取时不需要执行dedup命令呢?
nutch全网爬行的底层命令 -
wanggang0323:
这个网页的抽取有进展了吗?是否可以交流一下。qq3928754 ...
模板抽取思路的分析
今尝试下给nutch1.2增加一个插件,于是到官网找了个例子,链接如下:
http://wiki.apache.org/nutch/WritingPluginExample-0.9
这个例子实现的的是推荐网站,就是写关键字在content里,当别人搜索这个关键字时,你推荐的网站在搜索结果中排前,要实现推荐必须在你的网页上加上
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<meta name="recommended" content="plugins" />
<meta name="recommended" content="plugins" />
这条属性才能被插件识别。
由于它这个例子是用nutch0.9的,而且1.2和0.9有些区别,于是要修改一些代码。步骤如下:
1.插件开放
1.1在src/plugin中新建一个文件夹recommend
1.2.在recommend目录下新建Plugin.xml和Build.xml文件,内容如下:
Plugin.xml
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<?xml version="1.0" encoding="UTF-8"?>
<plugin
id="recommended"
name="Recommended Parser/Filter"
version="0.0.1"
provider-name="nutch.org">
<runtime>
<!-- As defined in build.xml this plugin will end up bundled as recommended.jar -->
<library name="recommended.jar">
<export name="*"/>
</library>
</runtime>
<!-- The RecommendedParser extends the HtmlParseFilter to grab the contents of
any recommended meta tags -->
<extension id="org.apache.nutch.parse.recommended.recommendedfilter"
name="Recommended Parser"
point="org.apache.nutch.parse.HtmlParseFilter">
<implementation id="RecommendedParser"
class="org.apache.nutch.parse.recommended.RecommendedParser"/>
</extension>
<!-- TheRecommendedIndexer extends the IndexingFilter in order to add the contents
of the recommended meta tags (as found by the RecommendedParser) to the lucene
index. -->
<extension id="org.apache.nutch.parse.recommended.recommendedindexer"
name="Recommended identifier filter"
point="org.apache.nutch.indexer.IndexingFilter">
<implementation id="RecommendedIndexer"
class="org.apache.nutch.parse.recommended.RecommendedIndexer"/>
</extension>
<!-- The RecommendedQueryFilter gets called when you perform a search. It runs a
search for the user's query against the recommended fields. In order to get
add this to the list of filters that gets run by default, you have to use
"fields=DEFAULT". -->
<extension id="org.apache.nutch.parse.recommended.recommendedSearcher"
name="Recommended Search Query Filter"
point="org.apache.nutch.searcher.QueryFilter">
<implementation id="RecommendedQueryFilter"
class="org.apache.nutch.parse.recommended.RecommendedQueryFilter">
<parameter name="fields" value="recommended"/>
</implementation>
</extension>
</plugin>
<?xml version="1.0" encoding="UTF-8"?>
<plugin
id="recommended"
name="Recommended Parser/Filter"
version="0.0.1"
provider-name="nutch.org">
<runtime>
<!-- As defined in build.xml this plugin will end up bundled as recommended.jar -->
<library name="recommended.jar">
<export name="*"/>
</library>
</runtime>
<!-- The RecommendedParser extends the HtmlParseFilter to grab the contents of
any recommended meta tags -->
<extension id="org.apache.nutch.parse.recommended.recommendedfilter"
name="Recommended Parser"
point="org.apache.nutch.parse.HtmlParseFilter">
<implementation id="RecommendedParser"
class="org.apache.nutch.parse.recommended.RecommendedParser"/>
</extension>
<!-- TheRecommendedIndexer extends the IndexingFilter in order to add the contents
of the recommended meta tags (as found by the RecommendedParser) to the lucene
index. -->
<extension id="org.apache.nutch.parse.recommended.recommendedindexer"
name="Recommended identifier filter"
point="org.apache.nutch.indexer.IndexingFilter">
<implementation id="RecommendedIndexer"
class="org.apache.nutch.parse.recommended.RecommendedIndexer"/>
</extension>
<!-- The RecommendedQueryFilter gets called when you perform a search. It runs a
search for the user's query against the recommended fields. In order to get
add this to the list of filters that gets run by default, you have to use
"fields=DEFAULT". -->
<extension id="org.apache.nutch.parse.recommended.recommendedSearcher"
name="Recommended Search Query Filter"
point="org.apache.nutch.searcher.QueryFilter">
<implementation id="RecommendedQueryFilter"
class="org.apache.nutch.parse.recommended.RecommendedQueryFilter">
<parameter name="fields" value="recommended"/>
</implementation>
</extension>
</plugin>
Build.xml
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<?xml version="1.0"?>
<project name="recommended" default="jar-core">
<import file="../build-plugin.xml"/>
<!-- Build compilation dependencies -->
<target name="deps-jar">
<ant target="jar" inheritall="false" dir="../lib-xml"/>
</target>
<!-- Add compilation dependencies to classpath -->
<path id="plugin.deps">
<fileset dir="${nutch.root}/build">
<include name="**/lib-xml/*.jar" />
</fileset>
</path>
<!-- Deploy Unit test dependencies -->
<target name="deps-test">
<ant target="deploy" inheritall="false" dir="../lib-xml"/>
<ant target="deploy" inheritall="false" dir="../nutch-extensionpoints"/>
<ant target="deploy" inheritall="false" dir="../protocol-file"/>
</target>
<!-- for junit test -->
<mkdir dir="${build.test}/data"/>
<copy file="data/recommended.html" todir="${build.test}/data"/>
</project>
<?xml version="1.0"?>
<project name="recommended" default="jar-core">
<import file="../build-plugin.xml"/>
<!-- Build compilation dependencies -->
<target name="deps-jar">
<ant target="jar" inheritall="false" dir="../lib-xml"/>
</target>
<!-- Add compilation dependencies to classpath -->
<path id="plugin.deps">
<fileset dir="${nutch.root}/build">
<include name="**/lib-xml/*.jar" />
</fileset>
</path>
<!-- Deploy Unit test dependencies -->
<target name="deps-test">
<ant target="deploy" inheritall="false" dir="../lib-xml"/>
<ant target="deploy" inheritall="false" dir="../nutch-extensionpoints"/>
<ant target="deploy" inheritall="false" dir="../protocol-file"/>
</target>
<!-- for junit test -->
<mkdir dir="${build.test}/data"/>
<copy file="data/recommended.html" todir="${build.test}/data"/>
</project>
1.3.在recommended目录下建立\src\java\org\apache\nutch\parse\recommended目录。
1.4.增加RecommendedIndexer.java,RecommendedParser.java,RecommendedQueryFilter.java三个类,内容如下:
RecommendedIndexer.java
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package org.apache.nutch.parse.recommended;
// JDK import
import java.util.logging.Logger;
// Commons imports
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
// Nutch imports
import org.apache.nutch.util.LogUtil;
import org.apache.nutch.fetcher.FetcherOutput;
import org.apache.nutch.indexer.IndexingFilter;
import org.apache.nutch.indexer.IndexingException;
import org.apache.nutch.indexer.NutchDocument;
import org.apache.nutch.parse.Parse;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.apache.nutch.crawl.CrawlDatum;
import org.apache.nutch.crawl.Inlinks;
// Lucene imports
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Document;
public class RecommendedIndexer implements IndexingFilter {
public static final Log LOG = LogFactory.getLog(RecommendedIndexer.class.getName());
private Configuration conf;
public RecommendedIndexer() {
}
@Override
public NutchDocument filter(NutchDocument doc, Parse parse, Text url,
CrawlDatum datum, Inlinks inlinks)
throws IndexingException {
String recommendation = parse.getData().getMeta("recommended");
if (recommendation != null) {
Field recommendedField =
new Field("recommended", recommendation,
Field.Store.YES, Field.Index.NOT_ANALYZED);
recommendedField.setBoost(5.0f);
doc.add("recommended",recommendedField);
LOG.info("Added " + recommendation + " to the recommended Field");
}
return doc;
}
public void setConf(Configuration conf) {
this.conf = conf;
}
public Configuration getConf() {
return this.conf;
}
@Override
public void addIndexBackendOptions(Configuration conf) {
// TODO Auto-generated method stub
}
}
package org.apache.nutch.parse.recommended;
// JDK import
import java.util.logging.Logger;
// Commons imports
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
// Nutch imports
import org.apache.nutch.util.LogUtil;
import org.apache.nutch.fetcher.FetcherOutput;
import org.apache.nutch.indexer.IndexingFilter;
import org.apache.nutch.indexer.IndexingException;
import org.apache.nutch.indexer.NutchDocument;
import org.apache.nutch.parse.Parse;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.apache.nutch.crawl.CrawlDatum;
import org.apache.nutch.crawl.Inlinks;
// Lucene imports
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Document;
public class RecommendedIndexer implements IndexingFilter {
public static final Log LOG = LogFactory.getLog(RecommendedIndexer.class.getName());
private Configuration conf;
public RecommendedIndexer() {
}
@Override
public NutchDocument filter(NutchDocument doc, Parse parse, Text url,
CrawlDatum datum, Inlinks inlinks)
throws IndexingException {
String recommendation = parse.getData().getMeta("recommended");
if (recommendation != null) {
Field recommendedField =
new Field("recommended", recommendation,
Field.Store.YES, Field.Index.NOT_ANALYZED);
recommendedField.setBoost(5.0f);
doc.add("recommended",recommendedField);
LOG.info("Added " + recommendation + " to the recommended Field");
}
return doc;
}
public void setConf(Configuration conf) {
this.conf = conf;
}
public Configuration getConf() {
return this.conf;
}
@Override
public void addIndexBackendOptions(Configuration conf) {
// TODO Auto-generated method stub
}
}
RecommendedParser.java
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package org.apache.nutch.parse.recommended;
// JDK imports
import java.util.Enumeration;
import java.util.Properties;
import java.util.logging.Logger;
// Nutch imports
import org.apache.hadoop.conf.Configuration;
import org.apache.nutch.metadata.Metadata;
import org.apache.nutch.parse.HTMLMetaTags;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.parse.HtmlParseFilter;
import org.apache.nutch.parse.ParseResult;
import org.apache.nutch.protocol.Content;
// Commons imports
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
// W3C imports
import org.w3c.dom.DocumentFragment;
public class RecommendedParser implements HtmlParseFilter {
private static final Log LOG = LogFactory.getLog(RecommendedParser.class.getName());
private Configuration conf;
/** The Recommended meta data attribute name */
public static final String META_RECOMMENDED_NAME="recommended";
/**
* Scan the HTML document looking for a recommended meta tag.
*/
@Override
public ParseResult filter(Content content, ParseResult parseResult,
HTMLMetaTags metaTags, DocumentFragment doc) {
// Trying to find the document's recommended term
String recommendation = null;
Properties generalMetaTags = metaTags.getGeneralTags();
for (Enumeration tagNames = generalMetaTags.propertyNames(); tagNames.hasMoreElements(); ) {
if (tagNames.nextElement().equals("recommended")) {
System.out.println(generalMetaTags.getProperty("recommended"));
recommendation = generalMetaTags.getProperty("recommended");
LOG.info("Found a Recommendation for " + recommendation);
}
}
if (recommendation == null) {
LOG.info("No Recommendation");
} else {
LOG.info("Adding Recommendation for " + recommendation);
Parse parse = parseResult.get(content.getUrl());
parse.getData().getContentMeta().set(META_RECOMMENDED_NAME, recommendation);
}
return parseResult;
}
public void setConf(Configuration conf) {
this.conf = conf;
}
public Configuration getConf() {
return this.conf;
}
}
package org.apache.nutch.parse.recommended;
// JDK imports
import java.util.Enumeration;
import java.util.Properties;
import java.util.logging.Logger;
// Nutch imports
import org.apache.hadoop.conf.Configuration;
import org.apache.nutch.metadata.Metadata;
import org.apache.nutch.parse.HTMLMetaTags;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.parse.HtmlParseFilter;
import org.apache.nutch.parse.ParseResult;
import org.apache.nutch.protocol.Content;
// Commons imports
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
// W3C imports
import org.w3c.dom.DocumentFragment;
public class RecommendedParser implements HtmlParseFilter {
private static final Log LOG = LogFactory.getLog(RecommendedParser.class.getName());
private Configuration conf;
/** The Recommended meta data attribute name */
public static final String META_RECOMMENDED_NAME="recommended";
/**
* Scan the HTML document looking for a recommended meta tag.
*/
@Override
public ParseResult filter(Content content, ParseResult parseResult,
HTMLMetaTags metaTags, DocumentFragment doc) {
// Trying to find the document's recommended term
String recommendation = null;
Properties generalMetaTags = metaTags.getGeneralTags();
for (Enumeration tagNames = generalMetaTags.propertyNames(); tagNames.hasMoreElements(); ) {
if (tagNames.nextElement().equals("recommended")) {
System.out.println(generalMetaTags.getProperty("recommended"));
recommendation = generalMetaTags.getProperty("recommended");
LOG.info("Found a Recommendation for " + recommendation);
}
}
if (recommendation == null) {
LOG.info("No Recommendation");
} else {
LOG.info("Adding Recommendation for " + recommendation);
Parse parse = parseResult.get(content.getUrl());
parse.getData().getContentMeta().set(META_RECOMMENDED_NAME, recommendation);
}
return parseResult;
}
public void setConf(Configuration conf) {
this.conf = conf;
}
public Configuration getConf() {
return this.conf;
}
}
RecommendedQueryFilter.java
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package org.apache.nutch.parse.recommended;
import org.apache.nutch.searcher.FieldQueryFilter;
import java.util.logging.Logger;
// Commons imports
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class RecommendedQueryFilter extends FieldQueryFilter {
private static final Log LOG = LogFactory.getLog(RecommendedParser.class.getName());
public RecommendedQueryFilter() {
super("recommended", 5f);
LOG.info("Added a recommended query");
}
}
package org.apache.nutch.parse.recommended;
import org.apache.nutch.searcher.FieldQueryFilter;
import java.util.logging.Logger;
// Commons imports
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class RecommendedQueryFilter extends FieldQueryFilter {
private static final Log LOG = LogFactory.getLog(RecommendedParser.class.getName());
public RecommendedQueryFilter() {
super("recommended", 5f);
LOG.info("Added a recommended query");
}
}
1.5.在 src/plugin/build.xml 中的<target name="deploy"></target>中增加一行:
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<ant dir="recommended" target="deploy" />
<ant dir="recommended" target="deploy" />
1.6.运行cmd,切换到recommend目录,运行ant命令编译,插件开发完成。
1.7 让nutch识别你的插件
在conf/nutch-site.xml 中增加一下属性
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<property>
<name>plugin.includes</name>
<value>recommended|protocol-http|urlfilter-regex|parse-(text|html|js)|index-basic|query-(basic|site|url)|summary-basic|scoring-opic|urlnormalizer-(pass|regex|basic)</value>
<description>Regular expression naming plugin id names to
include. Any plugin not matching this expression is excluded.
In any case you need at least include the nutch-extensionpoints plugin. By
default Nutch includes crawling just HTML and plain text via HTTP,
and basic indexing and search plugins.
</description>
</property>
<property>
<name>plugin.includes</name>
<value>recommended|protocol-http|urlfilter-regex|parse-(text|html|js)|index-basic|query-(basic|site|url)|summary-basic|scoring-opic|urlnormalizer-(pass|regex|basic)</value>
<description>Regular expression naming plugin id names to
include. Any plugin not matching this expression is excluded.
In any case you need at least include the nutch-extensionpoints plugin. By
default Nutch includes crawling just HTML and plain text via HTTP,
and basic indexing and search plugins.
</description>
</property>
2.编写插件测试类
2.1 在src/plugin中/recommend目录下新建一个data目录,在data目录下新建一个html文件recommended.html内容如下:
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>recommended</title>
<meta name="generator" content="TextMate http://macromates.com/
">
<meta name="author" content="Ricardo J. Méndez">
<meta name="recommended" content="recommended-content"/>
<!-- Date: 2007-02-12 -->
</head>
<body>
Recommended meta tag test.
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>recommended</title>
<meta name="generator" content="TextMate http://macromates.com/
">
<meta name="author" content="Ricardo J. Méndez">
<meta name="recommended" content="recommended-content"/>
<!-- Date: 2007-02-12 -->
</head>
<body>
Recommended meta tag test.
</body>
</html>
2.2 在src/plugin中/recommend目录下新建src/test/org/apache/nutch/parse/recommended目录,增加TestRecommendedParser.java类,内容如下:
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package org.apache.nutch.parse.recommended;
import org.apache.nutch.metadata.Metadata;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.parse.ParseResult;
import org.apache.nutch.parse.ParseUtil;
import org.apache.nutch.protocol.Content;
import org.apache.hadoop.conf.Configuration;
import org.apache.nutch.util.NutchConfiguration;
import java.util.Properties;
import java.io.*;
import java.net.URL;
import junit.framework.TestCase;
/*
* Loads test page recommended.html and verifies that the recommended
* meta tag has recommended-content as its value.
*
*/
public class TestRecommendedParser extends TestCase {
private static final File testDir =
new File("H:/project/SearchEngine/Nutch1.2/src/plugin/recommended/data");
public void testPages() throws Exception {
pageTest(new File(testDir, "recommended.html"), "http://foo.com/
",
"recommended-content");
}
public void pageTest(File file, String url, String recommendation)
throws Exception {
String contentType = "text/html";
InputStream in = new FileInputStream(file);
ByteArrayOutputStream out = new ByteArrayOutputStream((int)file.length());
byte[] buffer = new byte[1024];
int i;
while ((i = in.read(buffer)) != -1) {
out.write(buffer, 0, i);
}
in.close();
byte[] bytes = out.toByteArray();
Configuration conf = NutchConfiguration.create();
Content content =
new Content(url, url, bytes, contentType, new Metadata(), conf);
Parse parse = new ParseUtil(conf).parseByExtensionId("parse-html",content).get(content.getUrl());
Metadata metadata = parse.getData().getContentMeta();
assertEquals(recommendation, metadata.get("recommended"));
assertTrue("somesillycontent" != metadata.get("recommended"));
}
}
package org.apache.nutch.parse.recommended;
import org.apache.nutch.metadata.Metadata;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.parse.ParseResult;
import org.apache.nutch.parse.ParseUtil;
import org.apache.nutch.protocol.Content;
import org.apache.hadoop.conf.Configuration;
import org.apache.nutch.util.NutchConfiguration;
import java.util.Properties;
import java.io.*;
import java.net.URL;
import junit.framework.TestCase;
/*
* Loads test page recommended.html and verifies that the recommended
* meta tag has recommended-content as its value.
*
*/
public class TestRecommendedParser extends TestCase {
private static final File testDir =
new File("H:/project/SearchEngine/Nutch1.2/src/plugin/recommended/data");
public void testPages() throws Exception {
pageTest(new File(testDir, "recommended.html"), "http://foo.com/
",
"recommended-content");
}
public void pageTest(File file, String url, String recommendation)
throws Exception {
String contentType = "text/html";
InputStream in = new FileInputStream(file);
ByteArrayOutputStream out = new ByteArrayOutputStream((int)file.length());
byte[] buffer = new byte[1024];
int i;
while ((i = in.read(buffer)) != -1) {
out.write(buffer, 0, i);
}
in.close();
byte[] bytes = out.toByteArray();
Configuration conf = NutchConfiguration.create();
Content content =
new Content(url, url, bytes, contentType, new Metadata(), conf);
Parse parse = new ParseUtil(conf).parseByExtensionId("parse-html",content).get(content.getUrl());
Metadata metadata = parse.getData().getContentMeta();
assertEquals(recommendation, metadata.get("recommended"));
assertTrue("somesillycontent" != metadata.get("recommended"));
}
}
2.3 用junit运行TestRecommendedParser.java测试。
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- 选择“Source”选项卡,将默认输出目录从`nutch1.2/bin`修改为`nutch1.2/_bin`。 - 对于bin文件夹,可以通过右键点击“Team” > “Restore”来恢复其内容。 3. **添加JAR包** - 通过“Add JARs”功能,将`...
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Nutch中文分词插件的编写与配置,由于Internet的迅猛发展,使得用户查找信息犹如大海捞针,而搜索引擎则能帮用户很好的解决这个问题。 Nutch是用java语言开发的,基于Lucene的完整的网络搜索引擎,并采用插件机制进行...
- **可扩展性**:通过简单的接口实现,开发者可以轻松地增加新功能,而无需修改Nutch的核心代码。 - **灵活性**:丰富的插件库使得用户可以根据自身需求选择或开发适合的插件。 - **可维护性**:每个插件专注于独立...
### Nutch插件深入研究 #### 一、Nutch插件概述 Nutch是一个开源的Web爬虫项目,由Apache软件基金会维护。它基于Hadoop,能够从互联网上抓取和索引网页,构建搜索引擎。Nutch的强大之处在于其高度可定制性,这主要...
例如,增加PDF文件的支持只需要找到或编写相应的插件即可。 3. **可维护性**:插件机制使得每个开发者只需要关注自己的部分,而不需要深入了解整个系统的内部运作细节。这大大简化了内核的维护工作,并且降低了错误...
### Nutch插件开发知识点详解 #### 一、Nutch插件系统概述 Nutch是一款开源的网络爬虫工具,其强大的灵活性与扩展性得益于其独特的插件系统设计。插件(Plugin)作为Nutch的核心组件之一,为用户提供了一种灵活的...