Hadoop的HDFS Java pai 讀寫操作

/*
 * 
 *         將本地文件或者HDFS上的某個文件內容寫入到新的文件中
 *         新的文件是HDFS上創建的
 * 
 */


import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.nio.ByteBuffer;
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;

public class Operate {
    /**
     * 讀取當地的文件內容，並在DFS上面新建一個文件，把讀取的內容寫到這個上面來
     * @param NewHdfsFileName
     * @param localSrc
     * @throws Exception
     */
    public static void localFileToNewHdfsFile(String NewHdfsFileName,String localSrc) throws Exception{
        //創建hadoop配置
        Configuration conf = new Configuration();
        conf.set("fs.default.name", "hdfs://nameserver:9000/");
        //創建文件系統
        FileSystem fs = FileSystem.get(conf);
        Path path = new Path("hdfs://nameserver:9000/oldFile/"+NewHdfsFileName);
        FSDataOutputStream fsos = fs.create(path);
        BufferedReader bReader = new BufferedReader(new FileReader(new File(localSrc)));
        String lineStr;
        int lineNum = 1;
        while((lineStr = bReader.readLine()) != null){
            System.out.println("第"+lineNum+"的內容是："+lineStr);
//            String string = lineStr+"\n";
            fsos.write(lineStr.getBytes("utf-8"));
            fsos.writeChars("\n");
            lineNum++;
        }
    }


    /**
     * 讀取DFS上面的一個文件的內容，並新建一個文件，吧讀取到的內容寫到這個新建的文件上面
     * @param NewHdfsFileName
     * @param OldHdfsFileName
     * @throws IOException
     */
    public static void HdfsfileToNewHdfsfile(String NewHdfsFileName,String OldHdfsFileName) throws IOException{
        Configuration conf = new Configuration();
        conf.set("fs.default.name", "hdfs://nameserver:9000/");
        FileSystem fs = FileSystem.get(conf);
        Path newPath = new Path("hdfs://nameserver:9000/newFile/"+NewHdfsFileName);
        Path oldPath = new Path("hdfs://nameserver:9000/oldFile/"+OldHdfsFileName);
        FSDataOutputStream fsos = fs.create(newPath);
        FSDataInputStream fsis = fs.open(oldPath);
        int num = fsis.available()/1024 + 1;
        byte[] bytes = new byte[1024];
        int lineNum = 1;
        while((fsis.read(bytes)) != -1){
            System.out.println(new String(bytes));
            fsos.write(bytes);
            lineNum++;
            if(num == lineNum){
                bytes = new byte[fsis.available()];
            }else{
                bytes = new byte[1024];
            }
        }
    }

    /**
     * main函數測試
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        localFileToNewHdfsFile("laoyang", "D:\\1.txt");
//        HdfsfileToNewHdfsfile("laoyang","laoyang");
    }
}