在eclipse下操作HDFS

//方法一通过一个类IOUtils来实现

写文件 create 读取文件 open 删除文件delete

创建目录 mkdirs 删除文件或目录 delete 列出目录的内容 listStatus 显示文件系统的目录和文件的元数据信息 getFileStatus

package hdfs;

import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.hadoop.fs.FsUrlStreamHandlerFactory;
import org.apache.hadoop.io.IOUtils;

public class App1 {

    /**
     * @param args
     */
                //首先定义一个连接hadoop的URI（标识符和URL做区别）
    public static final String HDFS_PATH="hdfs://hadoop:9000/hello";

public static void main(String[] args) throws  Exception {
        // TODO Auto-generated method stub
        //url不认识hdfs://所以需要解析器
        URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory());
                            //用静态类IOUtils.copyBytes()
        URL url = new URL(HDFS_PATH);
            InputStream in = url.openStream();

            IOUtils.copyBytes(in, System.out , 1024, true );

    }

}

//方法二用过类FileSystem中方法.mkdir   .create    .open   get
package hdfs;

import java.io.FileInputStream;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.FileSystemTestHelper.fileType;
import org.apache.hadoop.io.IOUtils;

public class App2 {

    public static final String HDFS_PATH="hdfs://hadoop:9000";
    public static final String DIR_PATH="/d1000";
    public static final String FILE_PATH="/d1000/f1000";
    public static void main(String[] args) throws Exception, URISyntaxException {
/*
        final  FileSystem fileSystem = FileSystem.get(new URI(HDFS_PATH),new Configuration() );

        //创建文件mkdir
        fileSystem.mkdirs(new Path(DIR_PATH));
        //上传文件create
        FSDataOutputStream out = fileSystem.create(new Path(FILE_PATH));
        FileInputStream in= new FileInputStream("C:/Users/Administrator/Desktop/01.txt");
        IOUtils.copyBytes(in,out,1024,true);
        //下载文件open
        final FSDataInputStream in2= fileSystem.open(new Path(FILE_PATH));
        IOUtils.copyBytes(in2, System.out, 1024,true );
        //删除文件delete
        fileSystem.delete(new Path(FILE_PATH), true);*/
        FileSystem fileSystem = FileSystem.get(new URI(HDFS_PATH),new Configuration());
        //mkdir
        fileSystem.mkdirs(new Path(DIR_PATH));
        //上传create创造目标通道
        FSDataOutputStream out = fileSystem.create(new Path(FILE_PATH));
        FileInputStream in = new FileInputStream("C:/Users/Administrator/Desktop/01.txt");
        IOUtils .copyBytes(in,out , 1024, true);
        //下载文件open一个通道
        FSDataInputStream in2 = fileSystem.open(new Path(FILE_PATH));
        IOUtils.copyBytes(in2, System.out ,1024,true);
        //删除delete
        fileSystem.delete(new Path(DIR_PATH),true );
    }

}