如何將nutch2.3的bin/crawl腳本改寫為java類
這篇文章將為大家詳細(xì)講解有關(guān)如何將nutch2.3的bin/crawl腳本改寫為java類，小編覺得挺實(shí)用的，因此分享給大家做個(gè)參考，希望大家閱讀完這篇文章后可以有所收獲。
在斗門等地區(qū)，都構(gòu)建了全面的區(qū)域性戰(zhàn)略布局，加強(qiáng)發(fā)展的系統(tǒng)性、市場(chǎng)前瞻性、產(chǎn)品創(chuàng)新能力，以專注、極致的服務(wù)理念，為客戶提供成都網(wǎng)站設(shè)計(jì)、做網(wǎng)站 網(wǎng)站設(shè)計(jì)制作按需求定制開發(fā),公司網(wǎng)站建設(shè),企業(yè)網(wǎng)站建設(shè),高端網(wǎng)站設(shè)計(jì),成都全網(wǎng)營銷推廣,外貿(mào)網(wǎng)站制作,斗門網(wǎng)站建設(shè)費(fèi)用合理。
將nutch3.3的bin/crawl腳本改寫為java類
nutch2.8以后，以前的主控代碼org.apache.nutch.crawl.Crawl類沒了，只剩下對(duì)應(yīng)的控制腳本bin/crawl，感覺在IDEA里面調(diào)試不方便，所以我了解了下shell腳本,根據(jù)nutch3.3的bin/crawl和bin/nutch腳本，把bin/crawl翻譯成了java的Crawl類以便在IDEA里面調(diào)試
代碼設(shè)計(jì)說明
我參考了nutch2.7的crawl類，nutch3.3的bin/crawl和bin/nutch,盡量按照shell腳本的原組織結(jié)構(gòu)和邏輯進(jìn)行翻譯，有些地方不能直接使用的，就稍作了修改。
主要的業(yè)務(wù)邏輯在
public int run(String[] args)方法里程序主入口是
main，調(diào)用ToolRunner.run(NutchConfiguration.create(), new Crawl(), args);執(zhí)行上面的run方法public void binNutch5j(String jobName,String commandLine,String options)相當(dāng)于bin/crawl腳本里函數(shù)__bin_nutch的功能public int runJob(String jobName,String commandLine,String options)相當(dāng)于腳本bin/nutch的功能，這里沒有像腳本中那樣用if-else，也沒有使用switch-case,而是采用反射創(chuàng)建相應(yīng)的jobpublic void preConfig(Configuration conf,String options)用于根據(jù)帶-D參數(shù) commonOptions等指令設(shè)置每個(gè)Job的配置項(xiàng)CLASS_MAP是靜態(tài)(static)屬性，一個(gè)記錄JobName和對(duì)應(yīng)的類名的映射關(guān)系的哈希表(HashMap)
gora BUG說明
我之前是在每個(gè)job是按照腳本使用batchId參數(shù)的，遇到了下面這個(gè)問題:
Gora MongoDB Exception, can't serialize Utf8
貌似是序列化問題，好像gora-0.6版本解決了這個(gè)BUG,但我的nutch代碼是gora-0.5的，不會(huì)升級(jí)，所以就簡(jiǎn)單的把-batchId參數(shù)去掉，使用-all參數(shù)就行了，這點(diǎn)在代碼里可以看到。
關(guān)于升級(jí)到gora-0.6,有空再研究好了。
通過這個(gè)腳本的改寫，我了解了腳本的基本使用，同時(shí)對(duì)之前看的java反射等知識(shí)進(jìn)行了實(shí)踐，并對(duì)nutch的完整爬取流程、主要控制邏輯有了深刻的印象。主要是前面那個(gè)gora的BUG卡了我?guī)滋?，我還以為自己翻譯的有問題，看來調(diào)試能力還需要加強(qiáng)。
java代碼
這段代碼是翻譯nutch3.3的bin/crawl和bin/nutch腳本
Crawl類加到在org.apache.nutch.crawl包下，源碼如下：
package org.apache.nutch.crawl;
/**
* Created by brianway on 2016/1/19.
* @author brianway
* @site brianway.github.io
* org.apache.nutch.crawl.Crawl;
*/
import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.nutch.fetcher.FetcherJob;
import org.apache.nutch.util.NutchConfiguration;
import org.apache.nutch.util.NutchTool;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.reflect.Constructor;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
// Commons Logging imports
//import org.apache.hadoop.fs.*;
//import org.apache.hadoop.mapred.*;
//import org.apache.nutch.util.HadoopFSUtil;
//import org.apache.nutch.util.NutchJob;
//import org.apache.nutch.crawl.InjectorJob;
//import org.apache.nutch.crawl.GeneratorJob;
//import org.apache.nutch.fetcher.FetcherJob;
//import org.apache.nutch.parse.ParserJob;
//import org.apache.nutch.crawl.DbUpdaterJob;
//import org.apache.nutch.indexer.IndexingJob;
//import org.apache.nutch.indexer.solr.SolrDeleteDuplicates;
public class Crawl extends NutchTool implements Tool{
public static final Logger LOG = LoggerFactory.getLogger(Crawl.class);
/* Perform complete crawling and indexing (to Solr) given a set of root urls and the -solr
parameter respectively. More information and Usage parameters can be found below. */
public static void main(String args[]) throws Exception {
int res = ToolRunner.run(NutchConfiguration.create(), new Crawl(), args);
System.exit(res);
}
//為了編譯過
@Override
public Map<String, Object> run(Map<String, Object> args) throws Exception {
return null;
}
@Override
public int run(String[] args) throws Exception {
if (args.length < 1) {
System.out.println
("Usage: Crawl -urls <urlDir> -crawlId <crawlID> -solr <solrURL> [-threads n] [-depth i] [-topN N]");
// ("Usage: crawl <seedDir> <crawlID> [<solrUrl>] <numberOfRounds>");
return -1;
}
// ------------check args---------
/*
//??！由腳本直譯的，感覺少參數(shù),所以注釋掉，換下面的方式
String seedDir = args[1];
String crawlID = args[2];
String solrUrl=null;
int limit=1;
if(args.length-1 == 3){
limit = Integer.parseInt(args[3]);
}else if(args.length-1 == 4){
solrUrl = args[3];
limit = Integer.parseInt(args[4]);
}else{
System.out.println("Unknown # of arguments "+(args.length-1));
System.out.println
("Usage: crawl <seedDir> <crawlID> [<solrUrl>] <numberOfRounds>");
return -1;
//"Usage: Crawl <urlDir> -solr <solrURL> [-dir d] [-threads n] [-depth i] [-topN N]"
//"Usage: crawl <seedDir> <crawlID> [<solrUrl>] <numberOfRounds>";
}
*/
String seedDir = null;
String crawlID = null;
String solrUrl=null;
int limit = 0;
long topN = Long.MAX_VALUE;
int threads = getConf().getInt("fetcher.threads.fetch", 10);
//parameter-format in crawl class is
// like nutch2.7 "Usage: Crawl <urlDir> -solr <solrURL> [-dir d] [-threads n] [-depth i] [-topN N]"
//not like nutch3.3 "Usage: crawl <seedDir> <crawlID> [<solrUrl>] <numberOfRounds>";
for (int i = 0; i < args.length; i++) {
if ("-urls".equals(args[i])) {
seedDir = args[++i];
} else if ("-crawlId".equals(args[i])) {
crawlID = args[++i];
} else if ("-threads".equals(args[i])) {
threads = Integer.parseInt(args[++i]);
} else if ("-depth".equals(args[i])) {
limit = Integer.parseInt(args[++i]);
} else if ("-topN".equals(args[i])) {
topN = Long.parseLong(args[++i]);
} else if ("-solr".equals(args[i])) {
solrUrl = args[++i];
i++;
} else {
System.err.println("Unrecognized arg " + args[i]);
return -1;
}
}
if(StringUtils.isEmpty(seedDir)){
System.out.println("Missing seedDir : crawl <seedDir> <crawlID> [<solrURL>] <numberOfRounds>");
return -1;
}
if(StringUtils.isEmpty(crawlID)){
System.out.println("Missing crawlID : crawl <seedDir> <crawlID> [<solrURL>] <numberOfRounds>");
return -1;
}
if(StringUtils.isEmpty(solrUrl)){
System.out.println("No SOLRURL specified. Skipping indexing.");
}
if(limit == 0) {
System.out.println("Missing numberOfRounds : crawl <seedDir> <crawlID> [<solrURL>] <numberOfRounds>");
return -1;
}
/**
* MODIFY THE PARAMETERS BELOW TO YOUR NEEDS
*/
//set the number of slaves nodes
int numSlaves = 1;
//and the total number of available tasks
// sets Hadoop parameter "mapred.reduce.tasks"
int numTasks = numSlaves<<1;
// number of urls to fetch in one iteration
// 250K per task?
//!!這里使用topN
long sizeFetchlist = topN;//numSlaves *5;
// time limit for feching
int timeLimitFetch=180;
//Adds <days> to the current time to facilitate
//crawling urls already fetched sooner then
//db.default.fetch.interval.
int addDays=0;
// note that some of the options listed here could be set in the
// corresponding hadoop site xml param file
String commonOptions="-D mapred.reduce.tasks="+numTasks+" -D mapred.child.java.opts=-Xmx1000m -D mapred.reduce.tasks.speculative.execution=false -D mapred.map.tasks.speculative.execution=false -D mapred.compress.map.output=true ";
preConfig(getConf(),commonOptions);
//initial injection
System.out.println("Injecting seed URLs");
String inject_args = seedDir+" -crawlId "+crawlID;
binNutch5j("inject",inject_args,commonOptions);
for(int a=1;a<=limit;a++){
//-----------generating-------------
System.out.println("Generating batchId");
String batchId = System.currentTimeMillis()+"-"+new Random().nextInt(32767);
System.out.println("Generating a new fetchlist");
String generate_args = "-topN "+ sizeFetchlist +" -noNorm -noFilter -adddays "+addDays+" -crawlId "+crawlID+" -batchId "+batchId;
//String generate_options = commonOptions;
int res = runJob("generate",generate_args,commonOptions);
System.out.println("binNutch5j generate "+generate_args);
if(res==0){
}else if(res == 1){
System.out.println("Generate returned 1 (no new segments created)");
System.out.println("Escaping loop: no more URLs to fetch now");
break;
}else{
System.out.println("Error running:");
System.out.println("binNutch5j generate "+generate_args);
System.out.println("Failed with exit value "+res);
return res;
}
//--------fetching-----------
System.out.println("Fetching : ");
//String fetch_args = batchId+" -crawlId "+crawlID+" -threads "+threads;
String fetch_args = "-all"+" -crawlId "+crawlID+" -threads "+threads;
String fetch_options = commonOptions+" -D fetcher.timelimit.mins="+timeLimitFetch;
//10 threads
binNutch5j("fetch",fetch_args,fetch_options);
//----------parsing--------------
// parsing the batch
//
if(!getConf().getBoolean(FetcherJob.PARSE_KEY, false)){
System.out.println("Parsing : ");
//enable the skipping of records for the parsing so that a dodgy document
// so that it does not fail the full task
//String parse_args = batchId+" -crawlId "+crawlID;
String parse_args = "-all"+" -crawlId "+crawlID;
String skipRecordsOptions=" -D mapred.skip.attempts.to.start.skipping=2 -D mapred.skip.map.max.skip.records=1";
binNutch5j("parse",parse_args,commonOptions+skipRecordsOptions);
}
//----------updatedb------------
// updatedb with this batch
System.out.println("CrawlDB update for "+crawlID);
// String updatedb_args = batchId+" -crawlId "+crawlID;
String updatedb_args = "-all"+" -crawlId "+crawlID;
binNutch5j("updatedb",updatedb_args,commonOptions);
if(!StringUtils.isEmpty(solrUrl)){
System.out.println("Indexing "+ crawlID+ " on SOLR index -> " +solrUrl);
String index_args = batchId+" -all -crawlId "+crawlID;
String index_options = commonOptions+" -D solr.server.url="+solrUrl;
binNutch5j("index",index_args,index_options);
System.out.println("SOLR dedup -> "+solrUrl);
binNutch5j("solrdedup",solrUrl,commonOptions);
}else{
System.out.println("Skipping indexing tasks: no SOLR url provided.");
}
}
return 0;
}
/**
* 相當(dāng)于bin/crawl的函數(shù)__bin_nutch的功能
* @param jobName job
* @param commandLine
*/
public void binNutch5j(String jobName,String commandLine,String options)throws Exception{
int res = runJob(jobName,commandLine,options);
if(res!=0) {
System.out.println("Error running:");
System.out.println(jobName + " " + commandLine);
System.out.println("Error running:");
System.exit(res);
}
}
/**
* 相當(dāng)于腳本bin/nutch的功能
*
* @param jobName
* @param commandLine
* @return
*/
public int runJob(String jobName,String commandLine,String options)throws Exception{
//這里為了方便，沒有像腳本那樣用多個(gè)if-elif語句，也沒有用switch-case,直接用了反射來完成
Configuration conf = NutchConfiguration.create();
if(!StringUtils.isEmpty(options)){
preConfig(conf,options);
}
String[] args = commandLine.split("\\s+");
String className = CLASS_MAP.get(jobName);
Class<?> jobClass = Class.forName(className);
Constructor c = jobClass.getConstructor();
Tool job =(Tool) c.newInstance();
System.out.println("---------------runJob: "+jobClass.getName()+"----------------------");
return ToolRunner.run(conf, job, args);
}
/**
* 設(shè)置每個(gè)job的配置
* @param conf
* @param options
*/
public void preConfig(Configuration conf,String options){
String [] equations = options.split("\\s*-D\\s+");
System.out.println("options:"+options);
// i start from 1 not 0, skip the empty string ""
for (int i=1;i<equations.length;i++) {
String equation = equations[i];
String [] pair = equation.split("=");
//System.out.println(pair[0]+":"+pair[1]);
conf.set(pair[0],pair[1]);
//System.out.println("conf print: "+pair[0]+" "+conf.get(pair[0]));
}
}
/**
* the map to store the mapping relations jobName->ClassName
*/
public static HashMap<String,String> CLASS_MAP = new HashMap<String,String>();
/**
* init the CLASS_MAP，refer to "bin/nutch"
*/
static {
CLASS_MAP.put("inject","org.apache.nutch.crawl.InjectorJob");
CLASS_MAP.put("generate","org.apache.nutch.crawl.GeneratorJob");
CLASS_MAP.put("fetch","org.apache.nutch.fetcher.FetcherJob");
CLASS_MAP.put("parse","org.apache.nutch.parse.ParserJob");
CLASS_MAP.put("updatedb","org.apache.nutch.crawl.DbUpdaterJob");
CLASS_MAP.put("readdb","org.apache.nutch.crawl.WebTableReader");
CLASS_MAP.put("elasticindex","org.apache.nutch.indexer.elastic.ElasticIndexerJob");
CLASS_MAP.put("index","org.apache.nutch.indexer.IndexingJob");
CLASS_MAP.put("solrdedup","org.apache.nutch.indexer.solr.SolrDeleteDuplicates");
}
}關(guān)于“如何將nutch2.3的bin/crawl腳本改寫為java類”這篇文章就分享到這里了，希望以上內(nèi)容可以對(duì)大家有一定的幫助，使各位可以學(xué)到更多知識(shí)，如果覺得文章不錯(cuò)，請(qǐng)把它分享出去讓更多的人看到。
網(wǎng)站名稱：如何將nutch2.3的bin/crawl腳本改寫為java類
本文網(wǎng)址：http://jinyejixie.com/article38/gpgopp.html
成都網(wǎng)站建設(shè)公司_創(chuàng)新互聯(lián)，為您提供品牌網(wǎng)站制作、做網(wǎng)站、企業(yè)建站、外貿(mào)網(wǎng)站建設(shè)、網(wǎng)站維護(hù)、App開發(fā)
聲明：本網(wǎng)站發(fā)布的內(nèi)容（圖片、視頻和文字）以用戶投稿、用戶轉(zhuǎn)載內(nèi)容為主，如果涉及侵權(quán)請(qǐng)盡快告知，我們將會(huì)在第一時(shí)間刪除。文章觀點(diǎn)不代表本網(wǎng)站立場(chǎng)，如需處理請(qǐng)聯(lián)系客服。電話：028-86922220；郵箱：631063699@qq.com。內(nèi)容未經(jīng)允許不得轉(zhuǎn)載，或轉(zhuǎn)載時(shí)需注明來源： 創(chuàng)新互聯(lián)
- 網(wǎng)頁設(shè)計(jì)提高用戶體驗(yàn)設(shè)計(jì)之用戶執(zhí)行任務(wù)中減少重復(fù)操作 2022-05-26
- 購物網(wǎng)站制作用戶體驗(yàn)提高的幾大技巧？ 2022-06-06
- 企業(yè)做網(wǎng)站時(shí)清晰明了的風(fēng)格,不但利于用戶體驗(yàn),更利于搜索引擎抓取 2021-01-11
- APP應(yīng)用設(shè)計(jì)怎樣提升用戶體驗(yàn)？ 2016-08-17
- 網(wǎng)站布局的不好對(duì)用戶體驗(yàn)有影響嗎? 2014-11-12
- 網(wǎng)站建設(shè)關(guān)于用戶體驗(yàn)?zāi)切┦聝?/a> 2022-09-18
- 如何在網(wǎng)站建設(shè)細(xì)節(jié)當(dāng)中增加用戶體驗(yàn) 2016-12-20
- 想要提高網(wǎng)站效果，就需從用戶體驗(yàn)做起 2022-06-05
- 網(wǎng)站建設(shè)用戶體驗(yàn)之網(wǎng)站首頁細(xì)微設(shè)置 2015-08-30
- 淺談搜索引擎優(yōu)化和用戶體驗(yàn)優(yōu)化 2021-05-15
- 營銷網(wǎng)站在用戶體驗(yàn)和操作方面有什么特點(diǎn) 2016-11-16
- 改善用戶體驗(yàn)的幾個(gè)方法輕松提高網(wǎng)站銷售業(yè)績(jī) 2023-03-15