Question

我正在使用cdh5 quickstart vm，我有一个这样的文件（这里没有完整）：

{"user_id": "kim95",
 "type": "Book",
 "title": "Modern Database Systems: The Object Model, Interoperability, and
Beyond.",
 "year": "1995",
 "publisher": "ACM Press and Addison-Wesley",
 "authors": {},
 "source": "DBLP"
}
{"user_id": "marshallo79",
 "type": "Book",
 "title": "Inequalities: Theory of Majorization and Its Application.",
 "year": "1979",
 "publisher": "Academic Press",
 "authors": {("Albert W. Marshall"), ("Ingram Olkin")},
 "source": "DBLP"
}

我用过这个脚本：

books = load 'data/book-seded.json'
        using JsonLoader('t1:tuple(user_id:
chararray,type:chararray,title:chararray,year:chararray,publisher:chararray,source:chararray,authors:bag{T:tuple(author:chararray)})');

STORE books INTO 'book-no-seded.tsv';

脚本有效，但生成的文件是空的，你有什么想法吗？

Answer 1

最后，只有这个模式工作：如果我添加或删除与此配置不同的空格，那么我将会有一个错误（我还为元组添加了“name”，当它为空时指定了“null”，并更改了顺序在作者和来源之间，但即使没有这种配置，它仍然是错误的）

{"user_id": "kim95", "type": "Book","title": "Modern Database Systems: The Object Model, Interoperability, and Beyond.", "year": "1995", "publisher": "ACM Press and Addison-Wesley", "authors": [{"name":null"}], "source": "DBLP"}
{"user_id": "marshallo79", "type": "Book", "title": "Inequalities: Theory of Majorization and Its Application.", "year": "1979", "publisher": "Academic Press", "authors": [{"name":"Albert W. Marshall"},{"name":"Ingram Olkin"}], "source": "DBLP"}

工作脚本就是这个：

books = load 'data/book-seded-workings-reduced.json'
        using JsonLoader('user_id:chararray,type:chararray,title:chararray,year:chararray,publisher:chararray,authors:{(name:chararray)},source:chararray');

STORE books INTO 'book-table.csv';  //whether .tsv or .csv

Answer 2

使用USING org.apache.pig.piggybank.storage.JsonStorage（）;尝试将书籍输入INTO'book-no-seded.tsv'中。

Answer 3

您需要确保LOAD架构良好。您可以尝试DUMP books进行快速检查。

当我们在本教程http://gethue.com/hadoop-tutorials-ii-1-prepare-the-data-for-analysis/中使用Pig JsonLoader时，我们必须小心输入数据和模式。

猪：json装载机空的结果

3 个答案: