java操作hdfs

package hdfs;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;
import org.junit.Before;
import org.junit.Test;

public class HdfsClientEasy {

    private FileSystem fs = null;

    @Before
    public void getFs() throws Exception {

        // 拿到一个配置参数的封装对象，构造函数中就会对classpath下的xxx-site.xml文件进行解析
        // 真实的项目工程中就应该把xxx-site.xml文件加入到工程中来
        Configuration conf = new Configuration();
        // to set a parameter, figure out the filesystem is hdfs
        conf.set("fs.defaultFS", "hdfs://localhost:8000/");
        conf.set("dfs.replication", "1");

        // 获取到一个具体文件系统的客户端实例对象，产生的实例究竟是哪一种文件系统的客户端，是根据conf中的相关参数来决定
//        fs = FileSystem.get(conf);
        
        //这种获取fs的方法可以指定访问hdfs的客户端身份
        fs = FileSystem.get(new URI("hdfs://localhost:8000/"), conf, "wochu");

    }

    /**
     * 上传文件
     * 
     * @throws IllegalArgumentException
     * @throws IOException
     */
    @Test
    public void testUpload() throws IllegalArgumentException, IOException {
        fs.copyFromLocalFile(new Path("/Users/wochu/Desktop/tool/hdfs/test.txt"), new Path("/xue"));

    }

    /**
     * 删除文件
     * 
     * @throws IllegalArgumentException
     * @throws IOException
     */
    @Test
    public void testRmfile() throws IllegalArgumentException, IOException {

        boolean res = fs.delete(new Path("/xue"), true);

        System.out.println(res ? "delete is successfully :)"
                : "it is failed :(");

    }

    /**
     * 创建文件夹
     * 
     * @throws IllegalArgumentException
     * @throws IOException
     */
    @Test
    public void testMkdir() throws IllegalArgumentException, IOException {
        fs.mkdirs(new Path("/xue"));

    }

    /**
     * 重命名文件
     * 
     * @throws IllegalArgumentException
     * @throws IOException
     */
    @Test
    public void testRename() throws IllegalArgumentException, IOException {

        fs.rename(new Path("/xue/test.txt"), new Path("/xue/rename.txt"));

    }

    /**
     * 列出目录下的文件信息
     * 
     * @throws FileNotFoundException
     * @throws IllegalArgumentException
     * @throws IOException
     */
    @Test
    public void testListFiles() throws FileNotFoundException,
            IllegalArgumentException, IOException {

        // 递归列出文件
        RemoteIterator<LocatedFileStatus> listFiles = fs.listFiles(
                new Path("/"), true);

        while (listFiles.hasNext()) {

            LocatedFileStatus file = listFiles.next();

            System.out.println(file.getPath().getName());

        }

        System.out.println("--------------------------------------------");

        // 列出文件及文件夹
        FileStatus[] status = fs.listStatus(new Path("/"));
        for (FileStatus file : status) {

            System.out.println(file.getPath().getName() + "   "
                    + (file.isDirectory() ? "d" : "f"));

        }

    }

    /**
     * 从hdfs中下载数据到本地
     * 
     * @throws IllegalArgumentException
     * @throws IOException
     */
    @Test
    public void testDownload() throws IllegalArgumentException, IOException {

        fs.copyToLocalFile(new Path("/xue/rename.txt"), new Path("/Users/wochu/Desktop/tool/hdfs/name.txt"));

    }

}