How to make nutch run in eclipse ?-蒲公英云

[b][color=green][size=large]Nutch是一个优秀的开源的数据爬取框架，我们只需要简单的配置，就可以完成数据爬取，当然，Nutch里面也提供了很灵活的的插件机制，我们随时都可以对它进行二次开发，以满足我们的需求，本篇散仙，先来介绍下，如何在eclipse里面以local模式调试nutch，只有在eclipse里面把它弄清楚了，那么，我们学习起来，才会更加容易，因为，目前大多数人，使用nutch，都是基于命令行的操作，虽然很简单方便，但是想深入定制开发，就很困难，所以，散仙在本篇里，会介绍下nutch基本的调试，以及编译。
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[img]http://dl2.iteye.com/upload/attachment/0097/3205/931f90d0-b161-321a-a7b9-199d22819ad7.jpg\[/img\]
[color=green][size=large]nutch-site.xml里面的配置如下：[/size][/color]

<?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>

[b][color=green][size=large]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
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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;
    }
  }

[color=olive][size=large]在Generator里面的run方法改成[/size][/color]

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;
  }

[color=green][size=large]在Fetcher的run方法里面改动：[/size][/color]

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;
    }
  }

[b][color=green][size=large]在ParseSegment里面的run方法改动：[/size]
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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;
  }

[color=olive][size=large]在IndexingJob的run方法里面改动：[/size][/color]

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;
        }
    }

[color=green][size=large]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：[/size][/color]

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";

[b][color=green][size=large]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：[/size]
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[img]http://dl2.iteye.com/upload/attachment/0097/3216/ea040145-4cb7-3a72-8ecc-62e27df73922.jpg\[/img\]

[b][color=green][size=large]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.[/size][/color][/b]