Persistence4J - Java對象持久化
Persistence4j 是一個非常簡單的類庫，用于持久化數據至關系數據庫中。它個類庫可以不需要數據傳輸對象。只需創建一個POJO，然后利用這個類庫簡單的保存。這個類庫還集成了Java transaction API。支持的數據庫包括：Apache Derby ；H2 Database ；HSQLDB ；MySQL ；PostgreSQL。
//First lets create a simple pojo which you like to persist.
@Entity(schema="library",table="book")
public class Book{
@Column(isPrimaryKey=true)
private String isbn;
@Column
private String title;
@Column
private int authorid;
public Book(){
}
public Book(String isbn, String title, int authorid){
this.isbn = isbn;
this.title = title;
this.authorid = authorid;
}
// getters
}
DataProviderFactory dataProviderFactory = new DataProviderFactoryImpl(config);
String databaseName = "library";
String dbmsName = "mysql"
boolean isTransactional = false;
DataProvider dataProvider = dataProviderFactory.getDataProvider(databaseName, dbmsName, isTransactional);
// Now lets create a object of Book class and persist it
Book book = new Book("123432","TestBook",5);
TransferUtil.registerClass(Book.class);
GenericDAO<Book> genericDAO = new GenericDaoImpl<Book>(dataProvider.getDataFetcher());
//Persist Book
genericDAO.createEntity(book);
//Remove Book
genericDAO.deleteEntity(book);
//Test if Entity Exists
genericDAO.isEntityExists(book);
// findByPrimaryKey
Object obj[] = new Object[1];
obj[0] = "123432";
genericDAO.findByPrimaryKey(Book.class, obj);
//If you want to use transactions.This how to get TransactionService.
//Make sure isTransactional variable should be true and underlying dbms supports ACID.
TransactionService ts = dataProvider.getTransactionService();
try{
ts.beginTransaction();
genericDAO.createEntity(book);
ts.commitTransaction();
}catch(Exception exp){
ts.rollbackTransaction();
}
// Check the GenericDAO interface for all the available methods..
You can extend GenericDAOImpl and override the methods and add your own methods.</pre>