【Sesame】TripleStore添加三元数据
打算写一个sesame数据库的使用系列文章。这是第二篇,第一篇详见这里,讲解sesame数据库的搭建。 Sesame数据库添加triple三元组的方法有很多种,这里讲解两种,即单条添加与批量添加。 1. 建立数据库链接 Sesame数据库提供了几种数据存储办法,有本地数据库N
打算写一个sesame数据库的使用系列文章。这是第二篇,第一篇详见这里,讲解sesame数据库的搭建。
Sesame数据库添加triple三元组的方法有很多种,这里讲解两种,即单条添加与批量添加。
1. 建立数据库链接
Sesame数据库提供了几种数据存储办法,有本地数据库NativeStore,有基于内存的MemoryStore,有基于远程数据库的HTTP方式,还有基于关系型数据库存储方式的MySQLStore.声明变量:
private Repository repo; private MemoryStore memStore; private NativeStore natStore; private File repoFile; private RepositoryConnection repoConn;
基于内存MemoryStore:
/** * To get the repository within memory. */ public RepoUtil() { repoFile = new File(Const.repoPath); memStore = new MemoryStore(); repo = new SailRepository(memStore); }
基于本地NativeStore:
/** * To get the repository on the disk. * @param repoPath the repository file path */ public RepoUtil(String repoPath) { repoFile = new File(repoPath); natStore = new NativeStore(repoFile); repo = new SailRepository(natStore); }
基于网络HTTP Connection:
/** * To get the repository on the Http server. * @param server the server address * @param repoId the repository ID */ public RepoUtil(String server, String repoId) { repo = new HTTPRepository(server, repoId); }
基于关系型数据库MySQL:参考我的另一篇文章.
1.1. 初始化数据库
try { repo.initialize(); repoConn = repo.getConnection();//Get the connection from repository connection pool // repoConn.setAutoCommit(false);//why deprecate the setAutoCommit method? } catch(RepositoryException e) { e.printStackTrace(); }
2. 添加单条数据
2.1. 生成URI
此处提供函数用于生成URI,不需要如此麻烦,领会URI生成方法要领即可。先需要初始化URI、Literal生成器ValueFactory:ValueFactory valueFactory = new ValueFactoryImpl();
接下来即可生成URI:
/** * To get the URI of the specific string value * 1. if it is already a URI, then return; * 2. else translate it to URI format and return. * @param iden * @return the true URI */ public URI getUri(String iden) { URI rtn = null; String url = null; StringBuilder strRtn = new StringBuilder(uriBuilder); if(isUri(iden)) { System.out.println("isUri"); return valueFactory.createURI(iden); } else { try { url = URLEncoder.encode(iden,"utf-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } strRtn.append(url); rtn = valueFactory.createURI(strRtn.toString()); return rtn; } }
此处附上判断URI的函数(摘自网络)
/** * To justify if the input string is * in the format of URI. * @param obj * @return */ public boolean isUri(String obj) { return obj.matches("(([a-zA-Z][0-9a-zA-Z+\\\\-\\\\.]*:)?/{0,2}[0-9a-zA-Z;/?:@&=+$\\\\.\\\\-_!~*'()%]+)?(#[0-9a-zA-Z;/?:@&=+$\\\\.\\\\-_!~*'()%]+)?"); // return false; }
生成URI与Literal方法的简化版(会忽略某些问题,建议采用以上函数):
URI creativeWork = vf.createURI(namespace+"CreativeWork"); Literal about = vf.createLiteral(namespace+"about#"+"SomeString");
在构建好Connection、URI以及Literal以后,即可插入三元组:
/** * The URI-URI-Literal format SPO record. */ public void addRecord(URI subj, URI pred, Literal obj) { try { // repoConn = repo.getConnection(); repoConn.add(subj, pred, obj); // repoConn.close(); } catch (RepositoryException e) { e.printStackTrace(); } } /** * The URI-URI-URI format SPO record. */ public void addRecord(URI subj, URI pred, URI obj) { try { // repoConn = repo.getConnection(); repoConn.add(subj, pred, obj); // repoConn.close(); } catch (RepositoryException e) { e.printStackTrace(); } }
3、批量导入数据
如果有大量数据已经在文件中保存,我们不需要人工编写数据读取、写入的代码,直接通过Sesame已经提供的批量导入接口即可。File importFile = new File("segment"+j+".ttl"); String baseURI = "http://rk.com/import/test/"; RepositoryConnection con; try { FileReader fileReader = new FileReader(importFile); BufferedReader reader = new BufferedReader(fileReader); con = repo.getConnection(); con.add(reader, baseURI, RDFFormat.TURTLE); System.out.println("Add "+j+" ends."); con.close(); } catch (RepositoryException e) { e.printStackTrace(); } catch (RDFParseException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }
注意Java Heap的内存大小限制。可以查看这里修改Java虚拟机内存限制。
至此完成了Sesame数据写入的几种方法。下回介绍数据导出与数据修改。

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

Use ddrescue to recover data on Linux

Open source! Beyond ZoeDepth! DepthFM: Fast and accurate monocular depth estimation!

How to use Excel filter function with multiple conditions

The vitality of super intelligence awakens! But with the arrival of self-updating AI, mothers no longer have to worry about data bottlenecks

Google is ecstatic: JAX performance surpasses Pytorch and TensorFlow! It may become the fastest choice for GPU inference training

Slow Cellular Data Internet Speeds on iPhone: Fixes

The U.S. Air Force showcases its first AI fighter jet with high profile! The minister personally conducted the test drive without interfering during the whole process, and 100,000 lines of code were tested for 21 times.
