ormlite

http://www.ormlite.com/
3.封装与使用
下面我以一个Java Bean为例，简单的对ormlite进行封装。以下是一个聊天消息的JavaBean 取名为ChatMsgEntity
我们不需要在类的前面添加注解，此时，该类映射的数据库表的名称就是类的名称。我们在需要入库的每一个java bean的Field上添加注解，表示这对应着数据库中的字段。对于自增加的主键，我们使用generatedId = true 

package edu.njupt.zhb.model;import com.j256.ormlite.field.DatabaseField;/** * 一个聊天消息的JavaBean *@author: ZhengHaibo   *web:     http://blog.csdn.net/nuptboyzhb *mail:    [e-mail] *2013-12-23  Nanjing,njupt,China */public class ChatMsgEntity {@DatabaseField(generatedId = true)private int id;@DatabaseFieldprivate String nickName;//群组的昵称@DatabaseFieldprivate String name;// 消息来自@DatabaseFieldprivate String date;// 消息日期@DatabaseFieldprivate String message;// 消息内容@DatabaseFieldprivate int msgType;// 消息类型@DatabaseFieldprivate boolean recv = true;// 是否为收到的消息public int getMsgType() {return msgType;}public ChatMsgEntity() {}public ChatMsgEntity(String name, String date, String message, int msgType,boolean recv) {super();this.name = name;this.date = date;this.message = message;this.msgType = msgType;this.recv = recv;}public boolean isRecv() {return recv;}public void setRecv(boolean recv) {this.recv = recv;}public void setMsgType(int msgType) {this.msgType = msgType;}public String getName() {return name;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getNickName() {return nickName;}public void setNickName(String nickName) {this.nickName = nickName;}public void setName(String name) {this.name = name;}public String getDate() {return date;}public void setDate(String date) {this.date = date;}public String getMessage() {return message;}public void setMessage(String message) {this.message = message;}}

实现自己的OrmLiteSqliteOpenHelper

package edu.njupt.zhb.dao;import java.sql.SQLException;import java.util.concurrent.atomic.AtomicInteger;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import com.j256.ormlite.android.apptools.OrmLiteSqliteOpenHelper;import com.j256.ormlite.dao.Dao;import com.j256.ormlite.support.ConnectionSource;import com.j256.ormlite.table.TableUtils;import edu.njupt.zhb.model.ChatMsgEntity;/** * Database helper class used to manage the creation and upgrading of your database. This class also usually provides * the DAOs used by the other classes. */public class MsgDatabaseHelper extends OrmLiteSqliteOpenHelper {// name of the database file for your application -- change to something appropriate for your appprivate static final String DATABASE_NAME = "chatmsg.db";// any time you make changes to your database objects, you may have to increase the database versionprivate static final int DATABASE_VERSION = 3;// the DAO object we use to access the ChatMsgEntity tableprivate Dao<ChatMsgEntity, Integer> simpleDao = null;private static final AtomicInteger usageCounter = new AtomicInteger(0);// we do this so there is only one helperprivate static MsgDatabaseHelper helper = null;private MsgDatabaseHelper(Context context) {super(context, DATABASE_NAME, null, DATABASE_VERSION);}/** * Get the helper, possibly constructing it if necessary. For each call to this method, there should be 1 and only 1 * call to {@link #close()}. */public static synchronized MsgDatabaseHelper getHelper(Context context) {if (helper == null) {helper = new MsgDatabaseHelper(context);}usageCounter.incrementAndGet();return helper;}/** * This is called when the database is first created. Usually you should call createTable statements here to create * the tables that will store your data. */@Overridepublic void onCreate(SQLiteDatabase db, ConnectionSource connectionSource) {try {Log.i(MsgDatabaseHelper.class.getName(), "onCreate");TableUtils.createTable(connectionSource, ChatMsgEntity.class);} catch (SQLException e) {Log.e(MsgDatabaseHelper.class.getName(), "Can't create database", e);throw new RuntimeException(e);}}/** * This is called when your application is upgraded and it has a higher version number. This allows you to adjust * the various data to match the new version number. */@Overridepublic void onUpgrade(SQLiteDatabase db, ConnectionSource connectionSource, int oldVersion, int newVersion) {try {Log.i(MsgDatabaseHelper.class.getName(), "onUpgrade");TableUtils.dropTable(connectionSource, ChatMsgEntity.class, true);// after we drop the old databases, we create the new onesonCreate(db, connectionSource);} catch (SQLException e) {Log.e(MsgDatabaseHelper.class.getName(), "Can't drop databases", e);throw new RuntimeException(e);}}/** * Returns the Database Access Object (DAO) for our ChatMsgEntity class. It will create it or just give the cached * value. */public Dao<ChatMsgEntity, Integer> getChatMsgEntityDao() throws SQLException {if (simpleDao == null) {simpleDao = getDao(ChatMsgEntity.class);}return simpleDao;}/** * Close the database connections and clear any cached DAOs. For each call to {@link #getHelper(Context)}, there * should be 1 and only 1 call to this method. If there were 3 calls to {@link #getHelper(Context)} then on the 3rd * call to this method, the helper and the underlying database connections will be closed. */@Overridepublic void close() {if (usageCounter.decrementAndGet() == 0) {super.close();simpleDao = null;helper = null;}}}

定义Dao接口

/* * $filename: OrmSqliteDao.java,v $ * $Date: 2013-12-25  $ * Copyright (C) ZhengHaibo, Inc. All rights reserved. * This software is Made by Zhenghaibo. */package edu.njupt.zhb.dao;import java.util.List;import android.R.bool;/* *@author: ZhengHaibo   *web:     http://blog.csdn.net/nuptboyzhb *mail:    [e-mail] *2013-12-25  Nanjing,njupt,China */public interface OrmSqliteDao<T>{public boolean save(T object);public boolean saveOrUpdate(T object);public List<T> find();public boolean update(T object);public boolean delete(T object);public boolean deleteAll();public boolean executeSql(String sql);public T  findById();}

实现OrmLiteDao的封装

/* * $filename: ChatMsgEntityDao.java,v $ * $Date: 2013-12-25  $ * Copyright (C) ZhengHaibo, Inc. All rights reserved. * This software is Made by Zhenghaibo. */package edu.njupt.zhb.dao;import java.sql.SQLException;import java.util.List;import android.content.Context;import com.j256.ormlite.dao.Dao;import edu.njupt.zhb.model.ChatMsgEntity;/* *@author: ZhengHaibo   *web:     http://blog.csdn.net/nuptboyzhb *mail:    [e-mail] *2013-12-25  Nanjing,njupt,China */public class ChatMsgEntityDao implements OrmSqliteDao<ChatMsgEntity> {private Dao<ChatMsgEntity, Integer> simpleDao = null;public ChatMsgEntityDao(Context context) {// TODO Auto-generated constructor stubtry {simpleDao = MsgDatabaseHelper.getHelper(context).getChatMsgEntityDao();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}@Overridepublic boolean save(ChatMsgEntity object) {// TODO Auto-generated method stubtry {simpleDao.create(object);return true;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return false;}@Overridepublic List<ChatMsgEntity> find() {// TODO Auto-generated method stubtry {List<ChatMsgEntity> result = simpleDao.queryForAll();return result;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return null;}@Overridepublic boolean update(ChatMsgEntity object) {// TODO Auto-generated method stubtry {simpleDao.update(object);return true;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return false;}@Overridepublic boolean delete(ChatMsgEntity object) {// TODO Auto-generated method stubtry {simpleDao.delete(object);return true;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return false;}@Overridepublic ChatMsgEntity findById() {// TODO Auto-generated method stubreturn null;}@Overridepublic boolean deleteAll() {// TODO Auto-generated method stubtry {List<ChatMsgEntity> list = simpleDao.queryForAll();for(ChatMsgEntity msg:list){delete(msg);}return true;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return false;}@Overridepublic boolean saveOrUpdate(ChatMsgEntity object) {// TODO Auto-generated method stubtry {simpleDao.createOrUpdate(object);return true;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return false;}@Overridepublic boolean executeSql(String sql) {// TODO Auto-generated method stubtry {simpleDao.executeRaw(sql);return true;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return false;}}

在Activity中使用Dao对象

OrmSqliteDao<ChatMsgEntity> msgDao = new ChatMsgEntityDao(this);

然后就可以使用msgDao对ChatMsgEntity实体类进行“增删改查”的操作了。