Hadoop hdfs文件操作，mr demo,topN demo

package com.wwei.had241.demo.hdfs; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.URI; import java.net.URISyntaxException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FSDataOutputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IOUtils; public class HdfsDemo { private static FileSystem system = null; private static int buffSize = 4096; private static String loginUser = "root"; static{ Configuration config = new Configuration(); URI uri; try { uri = new URI("hdfs://hadoop07:9000"); system = FileSystem.get(uri, config,loginUser); } catch (URISyntaxException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } } public long startPro(){ System.out.println("start process ......"); return System.currentTimeMillis(); } public void endPro(long startTime){ System.out.println("end process!spend:" + (System.currentTimeMillis()-startTime)+"ms"); } /** * 创建文件目录 * @throws IOException **/ public void mkdir() throws IOException{ long startTime = startPro(); Path path = new Path("/d4"); boolean bool = system.mkdirs(path); System.out.println("mkdir result " + bool); endPro(startTime); } /** * 上传 * */ public void upload() throws IOException{ long startTime = startPro(); Path path = new Path("/word.txt"); FSDataOutputStream out = system.create(path); InputStream in = new FileInputStream("D:\\word.txt"); IOUtils.copyBytes(in, out, buffSize); endPro(startTime); } /** * 获取文件 * */ public void getFile() throws IOException{ long startTime = startPro(); Path path = new Path("/test1.txt"); InputStream in = system.open(path); // OutputStream out = new FileOutputStream("d:\\hello.txt"); OutputStream out = System.out; IOUtils.copyBytes(in, out, buffSize); endPro(startTime); } public void delect() throws IOException{ long startTime = startPro(); Path path = new Path("/d4"); boolean bool = system.deleteOnExit(path); System.out.println("delete file result:"+ bool); endPro(startTime); } public static void main(String[] args) { HdfsDemo demo = new HdfsDemo(); try { // demo.getFile(); demo.upload(); // demo.delect(); // demo.mkdir(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }