Question

我想在Hadoop Mapreduce中处理数据，我的数据格式低于非结构化，多行和未终止的引用。

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请提供代码片段如何处理上述数据？在此先感谢!!!!!!!

Answer 1

由于您要处理多行数据，因此无法使用简单的TextInputFormat来访问您的数据。因此，您需要为CSV文件使用自定义InputFormat。

目前在Hadoop中没有内置的处理多行CSV文件的方式（请参阅https://issues.apache.org/jira/browse/MAPREDUCE-2208），但幸运的是github上的代码可以尝试：https://github.com/mvallebr/CSVInputFormat。

就未终止的报价而言，可能有必要预先处理数据并首先将其清理干净。如果在引用之前或之后没有分隔符（"），则一个简单的规则是转义引号：

转义：a"b =＆gt; a\"b
保持不变：a;"b和a";b

另一种选择是纠正产生无效CSV的应用程序，以便以正确的方式转义数据。

在hadoop中处理非结构化和多行CSV

1 个答案: