HDFS操作全记录

部署服务端

1：下载hadoop-1.0.0.tar.gz

2：安装JDK 1.6

3：修改配置文件

core-site.xml

<configuration>
     <property>
         <name>fs.default.name</name>
         <value>hdfs://10.53.132.52:9000</value>
     </property>
</configuration>

hadoop-env.sh

export JAVA_HOME=/usr/java/jdk1.6.0_29

hdfs-site.xml

<configuration>
     <property>
         <name>dfs.replication</name>
         <value>1</value>
     </property>
     <property>
         <name>dfs.permissions</name>
         <value>false</value>
     </property>
</configuration>

mapred-site.xml

<configuration>
     <property>
         <name>mapred.job.tracker</name>
         <value>10.53.132.52:9001</value>
     </property>
</configuration>

masters，slaves 里面设置本机IP（不能为localhost）

赋予本机账户的ssh权限

$ ssh-keygen -t dsa -P '' -f ~/.ssh/id_dsa
$ cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys

4：开启

第一次运行要格式化文件系统，以后就不需要了。

$ bin/hadoop namenode -format

开启

$ bin/start-all.sh

验证

[root@linux52 ~]# jps
20255 NameNode
20565 SecondaryNameNode
20824 TaskTracker
20397 DataNode
20677 JobTracker
24738 Jps
[root@linux52 ~]#

调试java api

1：需要的库

1：JDK 1.6
2：commons-lang-2.2.jar
3：commons-configuration-1.6.jar
4：hadoop-core-1.0.0.jar
5：commons-logging-1.1.1.jar

2：代码

public class HDFSUtil {
    private static Logs log = new Logs(); ;
    public synchronized static FileSystem getFileSystem(String ip, int port) {
        FileSystem fs = null;
        String url = "hdfs://" + ip + ":" + String.valueOf(port);
        
        Configuration config = new Configuration();
        config.set("fs.default.name", url);
        try {
            fs = FileSystem.get(config);
        } catch (Exception e) { }
        return fs;
    }
    public synchronized static void listNode(FileSystem fs) {
        DistributedFileSystem dfs = (DistributedFileSystem) fs;
        try {
            DatanodeInfo[] infos = dfs.getDataNodeStats();
            for (DatanodeInfo node : infos) {
                System.out.println("HostName: " + node.getHostName() + "/n"
                        + node.getDatanodeReport());
                System.out.println("--------------------------------");
            }
        } catch (Exception e) { }
    }
    /**
     * 打印系统配置
     *
     * @param fs
     */
    public synchronized static void listConfig(FileSystem fs) {
        Iterator<Entry<String, String>> entrys = fs.getConf().iterator();
        while (entrys.hasNext()) {
            Entry<String, String> item = entrys.next();
            log.info(item.getKey() + ": " + item.getValue());
        }
    }
    /**
     * 创建目录和父目录
     *
     * @param fs
     * @param dirName
     */
    public synchronized static void mkdirs(FileSystem fs, String dirName) {
        // Path home = fs.getHomeDirectory();
        Path workDir = fs.getWorkingDirectory();
//        String dir = workDir + "/" + dirName;//以前的写法 create directory hdfs://10.53.132.52:9000/user/guoyanwei//tmp/testdir 
        String dir ="hdfs://10.53.132.52:9000" +  dirName;
        Path src = new Path(dir);
        // FsPermission p = FsPermission.getDefault();
        boolean succ;
        try {
            succ = fs.mkdirs(src);
            if (succ) {
                log.info("create directory " + dir + " successed. ");
            } else {
                log.info("create directory " + dir + " failed. ");
            }
        } catch (Exception e) {
            log.error("create directory " + dir + " failed :"+e );
        }
    }
    /**
     * 删除目录和子目录
     *
     * @param fs
     * @param dirName
     */
    public synchronized static void rmdirs(FileSystem fs, String dirName) {
        // Path home = fs.getHomeDirectory();
//        Path workDir = fs.getWorkingDirectory();
        String dir = "hdfs://10.53.132.52:9000" + "/" + dirName;
        Path src = new Path(dir);
        boolean succ;
        try {
            succ = fs.delete(src, true);
            if (succ) {
                log.info("remove directory " + dir + " successed. ");
            } else {
                log.info("remove directory " + dir + " failed. ");
            }
        } catch (Exception e) {
            log.error("remove directory " + dir + " failed :" );
        }
    }
    /**
     * 上传目录或文件
     *
     * @param fs
     * @param local
     * @param remote
     */
    public synchronized static void upload(FileSystem fs, String local,
            String remote) {
        // Path home = fs.getHomeDirectory();
//        Path workDir = fs.getWorkingDirectory();
        String dir ="hdfs://10.53.132.52:9000" +  remote;
        Path dst = new Path(dir);
        Path src = new Path(local);
        try {
            fs.copyFromLocalFile(false, true, src, dst);
            log.info("upload " + local + " to  " + remote + " successed. ");
        } catch (Exception e) {
            log.error("upload " + local + " to  " + remote + " failed :" );
        }
    }
    /**
     * 下载目录或文件
     *
     * @param fs
     * @param local
     * @param remote
     */
    public synchronized static void download(FileSystem fs, String local,
            String remote) {
        Path dst = new Path("hdfs://10.53.132.52:9000/" + remote);
        Path src = new Path(local);
        try {
            fs.copyToLocalFile(false, dst, src);
            log.info("download from " + remote + " to  " + local
                    + " successed. ");
        } catch (Exception e) {
            log.error("download from " + remote + " to  " + local + " failed :" );
        }
    }
    /**
     * 字节数转换
     *
     * @param size
     * @return
     */
    public synchronized static String convertSize(long size) {
        String result = String.valueOf(size);
        if (size < 1024 * 1024) {
            result = String.valueOf(size / 1024) + " KB";
        } else if (size >= 1024 * 1024 && size < 1024 * 1024 * 1024) {
            result = String.valueOf(size / 1024 / 1024) + " MB";
        } else if (size >= 1024 * 1024 * 1024) {
            result = String.valueOf(size / 1024 / 1024 / 1024) + " GB";
        } else {
            result = result + " B";
        }
        return result;
    }
    /**
     * 遍历HDFS上的文件和目录
     *
     * @param fs
     * @param path
     */
    public synchronized static void listFile(FileSystem fs, String path) {
        Path dst = new Path("hdfs://10.53.132.52:9000/" + path);
        try {
            String relativePath = "";
            FileStatus[] fList = fs.listStatus(dst);
            for (FileStatus f : fList) {
                if (null != f) {
                    relativePath = new StringBuffer()
                            .append(f.getPath().getParent()).append("/")
                            .append(f.getPath().getName()).toString();
                    if (f.isDir()) {
                        listFile(fs, relativePath);
                    } else {
                        System.out.println(convertSize(f.getLen()) + "/t/t"
                                + relativePath);
                    }
                }
            }
        } catch (Exception e) { } finally {
        }
    }
    public synchronized static void write(FileSystem fs, String path,
            String data) {
        Path dst = new Path("hdfs://10.53.132.52:9000/" + path);
        try {
            FSDataOutputStream dos = fs.create(dst);
            dos.writeUTF(data);
            dos.close();
            log.info("write content to " + path + " successed. ");
        } catch (Exception e) { }
    }
    public synchronized static String read(FileSystem fs, String path) {
        String content = null;
        Path dst = new Path("hdfs://10.53.132.52:9000/" + path);
        try {
            // reading
            FSDataInputStream dis = fs.open(dst);
            content = dis.readUTF();
            dis.close();
            log.info("read content from " + path + " successed. ");
        } catch (Exception e) { }
        return content;
    }

3：调用

    public static void main(String[] args) throws Exception {

        FileSystem fs = null;

        try {
            fs = HDFSUtil.getFileSystem("10.53.132.52", 9000);
            
            String dirName = "/tmp/test/aa";
            String localSrc = "d://8.log";

            String dst = "/tmp/8.log";
            
            //上传本地文件
            //HDFSUtil.upload(fs, localSrc ,dst);
            //HDFSUtil.listNode(fs);
            //创建目录
            //HDFSUtil.mkdirs(fs, dirName);
            //删除目录            
            //HDFSUtil.rmdirs(fs, dirName);
            //下载文件到本地
            //HDFSUtil.download(fs, localSrc, dst);
            //创建文件
            //HDFSUtil.write(fs, "/tmp/9.log", "test-测试");
            //读取文件
            //String content = HDFSUtil.read(fs, "/tmp/9.log");
            //System.out.println(content);
            //遍历文件夹
            //HDFSUtil.listFile(fs, "/tmp/");
            //遍历节点
            //HDFSUtil.listNode(fs);
            //遍历配置信息
            //HDFSUtil.listConfig(fs);
        } catch (Exception e) {
            // TODO: handle exception
        } finally {
            if (fs != null) {
                fs.close();
            }
        }

        System.out.println("over");
    }

4：管理地址

http://10.53.132.52:50070
http://10.53.132.52:50030

执行结果

后记

1：小文件系统需要研究 TFS

2：不同语言调用需要研究 Avro

文章谢绝转载，如有抄袭，按法律程序惩处！

　 Writer: XiuQuanShi

价值中国

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HDFS操作全记录

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