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How can I easily convert RDF triples to/from an idiomatic Java POJO business object?

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I'm a Java developer just getting started with linked data/RDF. I can create triples, put them in a triple store, query them, etc, but it's very awkward. Most of my code is focused on the mechanics of RDF and I'd really like to work with this data in a way that's more idiomatic Java. How can I convert a POJO to/from RDF triples with Jena without hand-coding everything? I'd like something that can convert a pile of triples with a defined structure back and forth between a Java POJO and RDF. Like JAXB or and ORM does for XML and a relational database, respectively. Also, I can't be locked in too

ES新提案：双问号操作符

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摘要：简单实用的新特性。原文： ES新提案：双问号操作符译者：前端小智本文主要讲 Gabriel Isenberg 撰写的ES提案 “Nullish coalescing for JavaScript” 。它提出 ?? 替换 || 的运算符,并提供默认值。这里先把这相提案叫作双问号操作符，如果你有好的叫法，欢迎留言讨论。 1. 概述双问号 ?? 的操作符跟 || 类似，如果给定变量值为 null 或者 undefined ，刚使用双问号后的默认值，否则使用该变量值。如下: > undefined ?? 'default' 'default' > null ?? 'default' 'default' > false ?? 'default' false > '' ?? 'default' '' > 0 ?? 'default' 0 2. 早期的 || 运算符号直接来个例子来演示一下 || 运算，下面两个等式是等价的： a || b a ? a : b 如果 a 是 truthy 值，则返回 a , 否则返回 b 。这使得使用 || 指定一个默认值成为可能，如果实际值是假的，那么将使用这个默认值： const result = actualValue || defaultValue; function getTitle(fileDesc) { return

RDF list subjects with their objects in a single line

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问题 I have an RDF file and I need to extract some information from it and write it to a file. I understood how it basically works, but I'm stuck with this: String queryString = "select ?person ?children where { ?person ?hasChildren ?children}"; TupleQuery tupleQuery = conn.prepareTupleQuery(QueryLanguage.SPARQL, queryString); TupleQueryResult result = tupleQuery.evaluate(); while (result.hasNext()) { BindingSet bindingSet = result.next(); Value p1 = bindingSet.getValue("person"); Value p2 =

How do I find where Sesame stores repositories?

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问题 I'm using booth Sesame .wars in Tomcat 7 on OS X 10.8, but now it doesn't work any more. I set up a new Tomcat with two new Sesame .war but now it uses the old repository. Where are these stored? (Couldn't add a new Repo or delete the old one). 回答1: Sesame Server by default stores its configuration data and database files in %APPDATA%\Aduna on Windows, $HOME/.aduna on Linux, and $HOME/Library/Application Support/Aduna on Mac OS X. If you want a completely new install, simply delete this