source: proiecte/HadoopJUnit/hadoop-0.20.1/src/docs/cn/src/documentation/content/xdocs/hadoop_archives.xml @ 120

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1<?xml version="1.0"?>
2<!--
3  Copyright 2002-2004 The Apache Software Foundation
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17<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V2.0//EN" "http://forrest.apache.org/dtd/document-v20.dtd">
18<document>
19        <header>
20        <title>Hadoop Archives</title>
21        </header>
22        <body>
23        <section>
24        <title> ä»€ä¹ˆæ˜¯Hadoop archives? </title>
25        <p>
26        Hadoop archives是特殊的档案栌匏。䞀䞪Hadoop archive对应䞀䞪文件系统目圕。
27        Hadoop archive的扩展名是*.har。Hadoop archive包含元数据圢匏是_index和_masterindx和数据part-*文件。_index文件包含了档案䞭的文件的文件名和䜍眮信息。
28        </p>
29        </section>
30        <section>
31        <title> åŠ‚䜕创建archive? </title>
32        <p>
33        <code>甚法: hadoop archive -archiveName name &lt;src&gt;* &lt;dest&gt;</code>
34        </p>
35        <p>
36        由-archiveName选项指定䜠芁创建的archive的名字。比劂foo.har。archive的名字的扩展名应该是*.har。蟓入是文件系统的路埄名路埄名的栌匏和平时的衚蟟方匏䞀样。创建的archive䌚保存到目标目圕䞋。泚意创建archives是䞀䞪Map/Reduce job。䜠应该圚map reduce集矀䞊运行这䞪呜什。䞋面是䞀䞪䟋子
37        </p>
38        <p>
39        <code>hadoop archive -archiveName foo.har /user/hadoop/dir1 /user/hadoop/dir2 /user/zoo/</code>
40        </p><p>
41        圚䞊面的䟋子䞭
42        /user/hadoop/dir1 和 /user/hadoop/dir2 䌚被園档到这䞪文件系统目圕䞋
43        -- /user/zoo/foo.har。圓创建archive时源文件䞍䌚被曎改或删陀。
44        </p>
45        </section>
46        <section>
47        <title> åŠ‚䜕查看archives䞭的文件? </title>
48        <p>
49        archive䜜䞺文件系统层暎露给倖界。所以所有的fs shell呜什郜胜圚archive䞊运行䜆是芁䜿甚䞍同的URI。
50        及倖archive是䞍可改变的。所以重呜名删陀和创建郜䌚返回错误。Hadoop Archives 的URI是
51        </p><p><code>har://scheme-hostname:port/archivepath/fileinarchive</code></p><p>
52        劂果没提䟛scheme-hostname它䌚䜿甚默讀的文件系统。这种情况䞋URI是这种圢匏
53        </p><p><code>
54        har:///archivepath/fileinarchive</code></p>
55        <p>
56        这是䞀䞪archive的䟋子。archive的蟓入是/dir。这䞪dir目圕包含文件fileafileb。
57        把/dir園档到/user/hadoop/foo.bar的呜什是
58        </p>
59        <p><code>hadoop archive -archiveName foo.har /dir /user/hadoop</code>
60        </p><p>
61        获埗创建的archive䞭的文件列衚䜿甚呜什
62        </p>
63        <p><code>hadoop dfs -lsr har:///user/hadoop/foo.har</code></p>
64        <p>查看archive侭的filea文件的呜什-
65        </p><p><code>hadoop dfs -cat har:///user/hadoop/foo.har/dir/filea</code></p>
66        </section>
67        </body>
68</document>
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