【Sesame】导出已经存在的三元组数据

【Sesame】导出已经存在的三元组数据

在Sesame系列上一篇介绍了如何添加三元组数据，本文将介绍如何导出三元组数据到文件。

1. 建立数据库连接

	static NativeStore nativeStore;
	static Repository repo;
	static String rdfFile;
	static {
		rdfFile = "exportTemp.ttl";
		repoFile = new File("ldbc");
		nativeStore = new NativeStore(repoFile);
		repo = new SailRepository(nativeStore);
	}

2. 初始化数据库连接

	public static void databaseInitialize() {
		try {
			repo.initialize();
		} catch (RepositoryException e) {
			e.printStackTrace();
		}
	}

3. 导出数据

	public static void outputDatabase(String filename) {
		try {
			FileOutputStream out = new FileOutputStream(filename);
			RDFWriter writer = Rio.createWriter(RDFFormat.TURTLE, out);
			RepositoryConnection newConn = repo.getConnection();
			newConn.export(writer);
		} catch (RepositoryException e) {
			e.printStackTrace();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (RDFHandlerException e) {
			e.printStackTrace();
		}
		System.out.println("-------Output ends--------");
	}