mahout协同过滤算法+hadoop1.x

本文采用mahout0.9版本，由于该版本天然支持hadoop1.x所以代码编写调用taste算法比较容易，但是hadoop2.x就不可以了

步骤：
1、将hadoop1.x安装目录下的三个配置文件拷贝到java项目的classpath根目录下，分别是core-site.xml，hdfs-site.xml和mapred-site.xml。
2、编写访问hdfs的dao类
代码如下：

public class HdfsDAO {

    private static final String HDFS = "hdfs://192.168.1.210:9000/";

    public HdfsDAO(Configuration conf) {
        this(HDFS, conf);
    }

    public HdfsDAO(String hdfs, Configuration conf) {
        this.hdfsPath = hdfs;
        this.conf = conf;
    }

    private String hdfsPath;
    private Configuration conf;

    public static void main(String[] args) throws IOException {
        JobConf conf = config();
        HdfsDAO hdfs = new HdfsDAO(conf);
        hdfs.copyFile("datafile/item.csv", "/tmp/new");
        hdfs.ls("/tmp/new");
    }        

    public static JobConf config(){
        JobConf conf = new JobConf(HdfsDAO.class);
        conf.setJobName("HdfsDAO");
        conf.addResource("classpath:/hadoop/core-site.xml");
        conf.addResource("classpath:/hadoop/hdfs-site.xml");
        conf.addResource("classpath:/hadoop/mapred-site.xml");
        return conf;
    }

    public void mkdirs(String folder) throws IOException {
        Path path = new Path(folder);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        if (!fs.exists(path)) {
            fs.mkdirs(path);
            System.out.println("Create: " + folder);
        }
        fs.close();
    }

    public void rmr(String folder) throws IOException {
        Path path = new Path(folder);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        fs.deleteOnExit(path);
        System.out.println("Delete: " + folder);
        fs.close();
    }

    public void ls(String folder) throws IOException {
        Path path = new Path(folder);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        FileStatus[] list = fs.listStatus(path);
        System.out.println("ls: " + folder);
        System.out.println("==========================================================");
        for (FileStatus f : list) {
            System.out.printf("name: %s, folder: %s, size: %d\n", f.getPath(), f.isDir(), f.getLen());
        }
        System.out.println("==========================================================");
        fs.close();
    }

    public void createFile(String file, String content) throws IOException {
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        byte[] buff = content.getBytes();
        FSDataOutputStream os = null;
        try {
            os = fs.create(new Path(file));
            os.write(buff, 0, buff.length);
            System.out.println("Create: " + file);
        } finally {
            if (os != null)
                os.close();
        }
        fs.close();
    }

    public void copyFile(String local, String remote) throws IOException {
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        fs.copyFromLocalFile(new Path(local), new Path(remote));
        System.out.println("copy from: " + local + " to " + remote);
        fs.close();
    }

    public void download(String remote, String local) throws IOException {
        Path path = new Path(remote);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        fs.copyToLocalFile(path, new Path(local));
        System.out.println("download: from" + remote + " to " + local);
        fs.close();
    }

    public void cat(String remoteFile) throws IOException {
        Path path = new Path(remoteFile);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        FSDataInputStream fsdis = null;
        System.out.println("cat: " + remoteFile);
        try {  
            fsdis =fs.open(path);
            IOUtils.copyBytes(fsdis, System.out, 4096, false);  
          } finally {  
            IOUtils.closeStream(fsdis);
            fs.close();
          }
    }

    public void location() throws IOException {
        // String folder = hdfsPath + "create/";
        // String file = "t2.txt";
        // FileSystem fs = FileSystem.get(URI.create(hdfsPath), new
        // Configuration());
        // FileStatus f = fs.getFileStatus(new Path(folder + file));
        // BlockLocation[] list = fs.getFileBlockLocations(f, 0, f.getLen());
        //
        // System.out.println("File Location: " + folder + file);
        // for (BlockLocation bl : list) {
        // String[] hosts = bl.getHosts();
        // for (String host : hosts) {
        // System.out.println("host:" + host);
        // }
        // }
        // fs.close();
    }

}

3、编写调用mahout的基于item的过滤算法代码

public class ItemCFHadoop1x {

    private static final String HDFS = "hdfs://192.168.1.210:9000";

    public static void main(String[] args) throws Exception {
        String localFile = "datafile/item.csv";
        String inPath = HDFS + "/user/hdfs/userCF";
        String inFile = inPath + "/item.csv";
        String outPath = HDFS + "/user/hdfs/userCF/result/";
        String outFile = outPath + "/part-r-00000";
        String tmpPath = HDFS + "/tmp/" + System.currentTimeMillis();

        JobConf conf = config();
        HdfsDAO hdfs = new HdfsDAO(HDFS, conf);
        hdfs.rmr(inPath);
        hdfs.mkdirs(inPath);
        hdfs.copyFile(localFile, inPath);
        hdfs.ls(inPath);
        hdfs.cat(inFile);

        StringBuilder sb = new StringBuilder();
        sb.append("--input ").append(inPath);
        sb.append(" --output ").append(outPath);
        sb.append(" --booleanData true");
        sb.append(" --similarityClassname org.apache.mahout.math.hadoop.similarity.cooccurrence.measures.EuclideanDistanceSimilarity");
        sb.append(" --tempDir ").append(tmpPath);
        args = sb.toString().split(" ");

        RecommenderJob job = new RecommenderJob();
        job.setConf(conf);
        job.run(args);

        hdfs.cat(outFile);
    }

    public static JobConf config() {
        JobConf conf = new JobConf(ItemCFHadoop1x.class);
        conf.setJobName("ItemCFHadoop");
        conf.addResource("classpath:/hadoop/core-site.xml");
        conf.addResource("classpath:/hadoop/hdfs-site.xml");
        conf.addResource("classpath:/hadoop/mapred-site.xml");
        return conf;
    }

}

4、将数据文件放在本地项目的根目录下，data.csv，内容如下：
1 101 5
1 102 3
1 103 2.5
2 101 2
2 102 2.5
2 103 5
2 104 2
3 101 2.5
3 104 4
3 105 4.5
3 107 5
4 101 5
4 103 3
4 104 4.5
4 106 4
5 101 4
5 102 3
5 103 2
5 104 4
5 105 3.5
5 106 4

至此，结束。