- 授权协议: Apache
- 开发语言: Java
- 操作系统: 跨平台
- 软件首页: http://code.google.com/p/jdbm2/
- 软件文档: http://jdbm2.googlecode.com/svn/trunk/javadoc/jdbm/package-summary.html
软件介绍
JDBM2 提供了 HashMap 和 TreeMap 的磁盘存储功能,简单易用,用于持久化数据。特别适合用于嵌入到其他应用程序中。示例代码:
/** create (or open existing) database */ String fileName = "helloWorld"; RecordManager recMan = RecordManagerFactory.createRecordManager(fileName); /** Creates TreeMap which stores data in database. * Constructor method takes recordName (something like SQL table name)*/ String recordName = "firstTreeMap"; PrimaryTreeMap treeMap = recMan.treeMap(recordName); /** add some stuff to map*/ treeMap.put(1, "One"); treeMap.put(2, "Two"); treeMap.put(3, "Three"); System.out.println(treeMap.keySet()); // > [1, 2, 3] /** Map changes are not persisted yet, commit them (save to disk) */ recMan.commit(); System.out.println(treeMap.keySet()); // > [1, 2, 3] /** Delete one record. Changes are not commited yet, but are visible. */ treeMap.remove(2); System.out.println(treeMap.keySet()); // > [1, 3] /** Did not like change. Roolback to last commit (undo record remove). */ recMan.rollback(); /** Key 2 was recovered */ System.out.println(treeMap.keySet()); // > [1, 2, 3] /** close record manager */ recMan.close();
你不知道的JavaScript(中卷)
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