下面进入正题,我们先来看下基本的步骤。
序号 | 名称 | 描述 |
1 | 安装部署ant | 编译nutch编码使用 |
2 | 下载nutch源码 | 必须步骤 |
3 | 在nutch源码根目录下,执行ant等待编译完成 | 构建nutch |
4 | 配置nutch-site.xml | 必须步骤 |
5 | ant eclipse 构建eclipse项目 | 导入eclipse中,调试 |
6 | conf目录置顶 | nutch加载时,会读取配置文件 |
7 | 执行org.apache.nutch.crawl.Injector注入种子 | local调试 |
8 | 执行org.apache.nutch.crawl.Generator生成一个抓取列表 | local调试 |
9 | 执行org.apache.nutch.fetcher.Fetcher生成一个抓取队列 | local调试 |
10 | 执行org.apache.nutch.parse.ParseSegment执行contet生一个段文件 | local调试 |
11 | 配置好solr服务 | 检索服务查询 |
12 | 执行org.apache.nutch.indexer.IndexingJob映射solr索引 | local调试 |
13 | 映射完成后,就可以solr里面执行查询了 | 校验结果 |
编译完,导入eclipse的中如下图所示,注意conf文件夹置顶:
nutch-site.xml里面的配置如下:
<?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?> <!-- Put site-specific property overrides in this file. --> <configuration> <property> <name>http.agent.name</name> <value>mynutch</value> </property> <property> <name>http.robots.agents</name> <value>*</value> <description>The agent strings we'll look for in robots.txt files, comma-separated, in decreasing order of precedence. You should put the value of http.agent.name as the first agent name, and keep the default * at the end of the list. E.g.: BlurflDev,Blurfl,* </description> </property> <property> <name>plugin.folders</name> <value>./src/plugin</value> <description>Directories where nutch plugins are located. Each element may be a relative or absolute path. If absolute, it is used as is. If relative, it is searched for on the classpath.</description> </property> </configuration>
下面简单介绍下,在各个类里运行,需要做的一些改动,首先运行nutch,是基于Hadoop的local模式调试的,所以,你得改变下hadoop的权限,否则在运行过程中,会报错。散仙在这里提供一个简单的方法,拷贝hadoop的FileUtils类进行eclipse中,修改它的权限校验即可,如果你是在linux上运行,就不需要考虑这个问题了。
在开始调试之前,你需要在项目的根目录下建一个urls文件夹,并新建一个种子文件放入你要抓取的网址。
在Injector类里面,run方法里,改成
public int run(String[] args) throws Exception { // if (args.length < 2) { // System.err.println("Usage: Injector <crawldb> <url_dir>"); // return -1; // } args=new String[]{"mydir","urls"};//urls try { inject(new Path(args[0]), new Path(args[1])); return 0; } catch (Exception e) { LOG.error("Injector: " + StringUtils.stringifyException(e)); return -1; } }
在Generator里面的run方法改成
public int run(String[] args) throws Exception { // if (args.length < 2) { // System.out // .println("Usage: Generator <crawldb> <segments_dir> [-force] [-topN N] [-numFetchers numFetchers] [-adddays numDays] [-noFilter] [-noNorm][-maxNumSegments num]"); // return -1; // } args=new String[]{"mydir","myseg","6","7",""}; Path dbDir = new Path(args[0]); Path segmentsDir = new Path(args[1]); long curTime = System.currentTimeMillis(); long topN = Long.MAX_VALUE; int numFetchers = -1; boolean filter = true; boolean norm = true; boolean force = false; int maxNumSegments = 1; for (int i = 2; i < args.length; i++) { if ("-topN".equals(args[i])) { topN = Long.parseLong(args[i + 1]); i++; } else if ("-numFetchers".equals(args[i])) { numFetchers = Integer.parseInt(args[i + 1]); i++; } else if ("-adddays".equals(args[i])) { long numDays = Integer.parseInt(args[i + 1]); curTime += numDays * 1000L * 60 * 60 * 24; } else if ("-noFilter".equals(args[i])) { filter = false; } else if ("-noNorm".equals(args[i])) { norm = false; } else if ("-force".equals(args[i])) { force = true; } else if ("-maxNumSegments".equals(args[i])) { maxNumSegments = Integer.parseInt(args[i + 1]); } } try { Path[] segs = generate(dbDir, segmentsDir, numFetchers, topN, curTime, filter, norm, force, maxNumSegments); if (segs == null) return -1; } catch (Exception e) { LOG.error("Generator: " + StringUtils.stringifyException(e)); return -1; } return 0; }
在Fetcher的run方法里面改动:
public int run(String[] args) throws Exception { String usage = "Usage: Fetcher <segment> [-threads n]"; args=new String[]{"D:\\20140520nutchplugin\\apache-nutch-1.8\\myseg\\20140520120541","4"}; // if (args.length < 1) { // System.err.println(usage); // return -1; // } Path segment = new Path(args[0]); int threads = getConf().getInt("fetcher.threads.fetch", 10); boolean parsing = false; for (int i = 1; i < args.length; i++) { // parse command line if (args[i].equals("-threads")) { // found -threads option threads = Integer.parseInt(args[++i]); } } getConf().setInt("fetcher.threads.fetch", threads); try { fetch(segment, threads); return 0; } catch (Exception e) { LOG.error("Fetcher: " + StringUtils.stringifyException(e)); return -1; } }
在ParseSegment里面的run方法改动:
public int run(String[] args) throws Exception { Path segment; String usage = "Usage: ParseSegment segment [-noFilter] [-noNormalize]"; // if (args.length == 0) { // System.err.println(usage); // System.exit(-1); // } args=new String[]{"D:\\20140520nutchplugin\\apache-nutch-1.8\\myseg\\20140520120541"}; if(args.length > 1) { for(int i = 1; i < args.length; i++) { String param = args[i]; if("-nofilter".equalsIgnoreCase(param)) { getConf().setBoolean("parse.filter.urls", false); } else if ("-nonormalize".equalsIgnoreCase(param)) { getConf().setBoolean("parse.normalize.urls", false); } } } segment = new Path(args[0]); parse(segment); return 0; }
在IndexingJob的run方法里面改动:
public int run(String[] args) throws Exception { args=new String[]{"mydir","D:\\20140520nutchplugin\\apache-nutch-1.8\\myseg\\20140520120541"}; if (args.length < 2) { System.err .println("Usage: Indexer <crawldb> [-linkdb <linkdb>] [-params k1=v1&k2=v2...] (<segment> ... | -dir <segments>) [-noCommit] [-deleteGone] [-filter] [-normalize]"); IndexWriters writers = new IndexWriters(getConf()); System.err.println(writers.describe()); return -1; } final Path crawlDb = new Path(args[0]); Path linkDb = null; final List<Path> segments = new ArrayList<Path>(); String params = null; boolean noCommit = false; boolean deleteGone = false; boolean filter = false; boolean normalize = false; for (int i = 1; i < args.length; i++) { if (args[i].equals("-linkdb")) { linkDb = new Path(args[++i]); } else if (args[i].equals("-dir")) { Path dir = new Path(args[++i]); FileSystem fs = dir.getFileSystem(getConf()); FileStatus[] fstats = fs.listStatus(dir, HadoopFSUtil.getPassDirectoriesFilter(fs)); Path[] files = HadoopFSUtil.getPaths(fstats); for (Path p : files) { segments.add(p); } } else if (args[i].equals("-noCommit")) { noCommit = true; } else if (args[i].equals("-deleteGone")) { deleteGone = true; } else if (args[i].equals("-filter")) { filter = true; } else if (args[i].equals("-normalize")) { normalize = true; } else if (args[i].equals("-params")) { params = args[++i]; } else { segments.add(new Path(args[i])); } } try { index(crawlDb, linkDb, segments, noCommit, deleteGone, params, filter, normalize); return 0; } catch (final Exception e) { LOG.error("Indexer: " + StringUtils.stringifyException(e)); return -1; } }
除此之外,还需要,在SolrIndexWriter的187行和SolrUtils的54行分别添加如下代码,修改solr的映射地址:
String serverURL = conf.get(SolrConstants.SERVER_URL); serverURL="http://localhost:8983/solr/";
// String serverURL = job.get(SolrConstants.SERVER_URL); String serverURL ="http://localhost:8983/solr";
按上面几个步骤,每执行一个类的时候,就修改其的运行参数,因为nutch的作业具有依赖性,这一个作业的输入,往往是上一个作业的输出,手动依次运行修改上面的5个类,最终我们的索引就可以生成在solr里,截图如下:
当然,我们还可以,配置分词策略,来使我们检索更加通用,准确.