HDFS内容追加

配置：hdfs-site.xml

<property>
	    <name>dfs.support.append</name>
	    <value>true</value>
</property>

追加一个文件

package com.wyp;

	import org.apache.hadoop.conf.Configuration;
	import org.apache.hadoop.fs.FileSystem;
	import org.apache.hadoop.fs.Path;
	import org.apache.hadoop.io.IOUtils;

	import java.io.*;
	import java.net.URI;

	/**
	 * blog: http://www.iteblog.com/
	 * Date: 14-1-2
	 * Time: 下午6:09
	 */
	public class AppendContent {
	    public static void main(String[] args) {
	        String hdfs_path = "hdfs://mycluster/home/wyp/wyp.txt";//文件路径
	        Configuration conf = new Configuration();
	        conf.setBoolean("dfs.support.append", true);

	        String inpath = "/home/wyp/append.txt";
	        FileSystem fs = null;
	        try {
	            fs = FileSystem.get(URI.create(hdfs_path), conf);
	            //要追加的文件流，inpath为文件
	            InputStream in = new
	                  BufferedInputStream(new FileInputStream(inpath));
	            OutputStream out = fs.append(new Path(hdfs_path));
	            IOUtils.copyBytes(in, out, 4096, true);
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	    }
	}

追加一行内容

/**
     * 以append方式将内容添加到HDFS上文件的末尾;注意：文件更新，需要在hdfs-site.xml中添<property><name>dfs.
     * append.support</name><value>true</value></property>
     */
    private static void appendToHdfs() throws FileNotFoundException,
            IOException {
        String dst = "hdfs://192.168.1.11:9000/usr/yujing/test.txt";
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(URI.create(dst), conf);
        FSDataOutputStream out = fs.append(new Path(dst));  

        int readLen = "zhangzk add by hdfs java api".getBytes().length;  

        while (-1 != readLen) {
            out.write("zhangzk add by hdfs java api".getBytes(), 0, readLen);
        }
        out.close();
        fs.close();
    }  

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