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();

    }