使用OrmLite持久化SQLite（续）

上回说到我们已经建立了实体类Account和Order，下面我们来对它进行一个OrmLite的注解。

@DatabaseTable(tableName = "accounts") //不写的话表名默认为类名(小写)account
public class Account implements Serializable {

	@DatabaseField(generatedId=true) //设置为自增长的主键
	private int aId;
	@DatabaseField //使用默认，列名与字段名相同
	private String aName;

	//一定要有一个无参的构造函数
	public Account() {
		super();
	}
.....
}

@DatabaseTable(tableName = "orders") 
public class Order implements Serializable {

	@DatabaseField(generatedId=true)
	private int oid;
	@DatabaseField 
	private String oName;
	@DatabaseField(foreign=true) //简单地写一个外键=true就行了 方便大家理解
	private Account account;
......
}

接着我们创建一个DataHelper类继承自OrmLiteSqliteOpenHelper（相当于数据库访问层）：

public class DataHelper extends OrmLiteSqliteOpenHelper {

	private static final String DATABASE_NAME = "test.db"; // 数据库名
	private static final int DATABASE_VERSION = 1; // 数据库版本号,以后如果对实体类进行了修改,想要更新一下数据库的话,改一下版本号就行了

	@SuppressWarnings("rawtypes")
	Map<String, Dao> daoMaps = null; // 所有DAO的集合，这不是必须的，你可以采用你的方式

	@SuppressWarnings("rawtypes")
	private void initDaoMaps() {
		daoMaps = new HashMap<String, Dao>();
		daoMaps.put("accountDao", null);
		daoMaps.put("orderDao", null);
	}

	public DataHelper(Context context) {
		super(context, DATABASE_NAME, null, DATABASE_VERSION); // 用过SQLite的都知道，我就不解释了
		initDaoMaps(); // 自定义方法 ,初始化dao的Map.
	}

	@Override
	public void onCreate(SQLiteDatabase db, ConnectionSource connectionSource) {
		// 数据库创建时自动执行,以后不会再自动执行
		try {
			TableUtils.createTable(connectionSource, Account.class); // 创建Account表
			TableUtils.createTable(connectionSource, Order.class); // 创建Order表
			Log.i(DataHelper.class.getName(), "创建数据库成功！");
		} catch (Exception e) {
			Log.i(DataHelper.class.getName(), "创建数据库失败！", e);
			e.printStackTrace();
		}
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, ConnectionSource connectionSource,
			int arg2, int arg3) {
		// 数据库检测到版本号不同时自动执行,在这里我们应该：
		try {
			// 1:删除原有的旧表
			TableUtils.dropTable(connectionSource, Account.class, true);
			TableUtils.dropTable(connectionSource, Order.class, true);
			// 2:创建现在的新表
			onCreate(db, connectionSource);
			Log.e(DataHelper.class.getName(), "更新数据库成功");
		} catch (SQLException e) {
			Log.e(DataHelper.class.getName(), "更新数据库失败", e);
			e.printStackTrace();
		}
	}

	@Override
	public void close() {
		super.close();
		daoMaps.clear();
	}

	//给它一个实体类，返回该实体类专用的Dao，功能很强大
	@SuppressWarnings("unchecked")
	public Dao<Account, Integer> getAccountDao() {
		Dao<Account, Integer> accountDao = daoMaps.get("accountDao");
		if (accountDao == null) {
			try {
				accountDao = getDao(Account.class);
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		return accountDao;
	}

	@SuppressWarnings("unchecked")
	public Dao<Order, Integer> getOrderDao() {
		Dao<Order, Integer> orderDao = daoMaps.get("orderDao");
		if (orderDao == null) {
			try {
				orderDao = getDao(Order.class);
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		return orderDao;
	}

}

然后写业务逻辑层Service ：

public class AccountService implements IAccountService{

	private Dao<Account, Integer> accountDao = null;

	public AccountService(Dao<Account, Integer> dao) {
		accountDao = dao;
	}

	public String reg(Account account) {
		boolean result = false;

		try {
			accountDao.create(account);
			result = true;
		} catch (SQLException e) {
			e.printStackTrace();
		}
		String msg= result ? "注册客户成功！" : "注册失败";
		return msg;
	}

	public Account load(String name) {
		Account account = null;

		Map<String, Object> accountMap = new HashMap<String, Object>();
		accountMap.put("aName", name);

		try {
			List<Account> list = accountDao.queryForFieldValues(accountMap);
			account = list != null && list.size() == 1 ? list.get(0) : null;
		} catch (SQLException e) {
			e.printStackTrace();
		}

		return account;
	}

}

OrderService与上类似 ，我就不贴出来占位置了，接着到了我们的UI层。

修改我们的Activity类，继承自OrmLiteBaseActivity<DataHelper>，这是一个抽象类OrmLiteBaseActivity<H extends OrmLiteSqliteOpenHelper>，它也是继承自Activity的，所以我们的Activity类相当于是间接继承自Activity：

public class OrmLiteTestActivity extends OrmLiteBaseActivity<DataHelper>
		implements OnClickListener {

	private Button btnRegAccount, btnAddOrder, btnShow;
	private TextView tvMsg = null;

	private IAccountService accountService = null;
	private IOrderService orderService = null;

	private int accountID = 0;
	private int orderID = 0;
	private String msg = "";

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		init();
	}

	private void init() {
		// 初始化service
		accountService = new AccountService(getHelper().getAccountDao());
		orderService = new OrderService(getHelper().getOrderDao());

		btnRegAccount = (Button) this.findViewById(R.id.btnRegAccount);
		btnAddOrder = (Button) this.findViewById(R.id.btnAddOrder);
		btnShow = (Button) this.findViewById(R.id.btnShow);
		tvMsg = (TextView) this.findViewById(R.id.tvMsg);

		btnRegAccount.setOnClickListener(this);
		btnAddOrder.setOnClickListener(this);
		btnShow.setOnClickListener(this);
	}

	@Override
	public void onClick(View v) {
		msg = "";
		switch (v.getId()) {
		case R.id.btnRegAccount:
			accountID++;
			Account account = new Account("客户" + accountID);
			msg = accountService.reg(account) ? "注册客户成功!" : "注册客户失败!";
			break;
		case R.id.btnAddOrder:
			orderID++;
			account = accountService.load("客户1");
			Order order = new Order("定单" + orderID, account);
			msg = orderService.addOrder(order) ? "添加定单成功!" : "添加定单失败!";
			break;
		case R.id.btnShow:
			List<Order> list = orderService.findOrderByAccountID(1);
			for (Order o : list) {
				msg += o.getOid() + ":" + o.getoName() + "\n";
			}
			break;
		default:
			break;
		}
		tvMsg.setText(msg);
	}
}

运行后效果如下： 最后是查找客户1的所有定单

这样我们就实现了使用OrmLite实现持久化数据了，完整代码可以在我的资源列表中下载：

http://download.csdn.net/detail/a_mean/3805488

欢迎交流、补充、找错，谢谢！