android orm映射框架（類似hibernate）基本使用

android  orm映射框架，可像hibernate一樣操作數據庫。  以下代碼是我從網上摘錄下來的，僅供參考.

package com.cng.utils; 
 
import java.sql.SQLException; 
 
import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.util.Log; 
 
import com.cng.modal.Hello; 
 
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; 
 
public class DataHelper extends OrmLiteSqliteOpenHelper 
{ 
 
    private static final String DATABASE_NAME = "HelloOrmlite.db"; 
    private static final int DATABASE_VERSION = 1; 
    private Dao<Hello, Integer> helloDao = null; 
 
    public DataHelper(Context context) 
    { 
        super(context, DATABASE_NAME, null, DATABASE_VERSION); 
    } 
 
    @Override 
    public void onCreate(SQLiteDatabase db, ConnectionSource connectionSource) 
    { 
        try 
        { 
            TableUtils.createTable(connectionSource, Hello.class); 
        } catch (SQLException e) 
        { 
            Log.e(DataHelper.class.getName(), "創建數據庫失敗", e); 
            e.printStackTrace(); 
        } 
    } 
 
    @Override 
    public void onUpgrade(SQLiteDatabase db, ConnectionSource connectionSource, 
            int arg2, int arg3) 
    { 
        try 
        { 
            TableUtils.dropTable(connectionSource, Hello.class, true); 
            onCreate(db, connectionSource); 
        } catch (SQLException e) 
        { 
            Log.e(DataHelper.class.getName(), "更新數據庫失敗", e); 
            e.printStackTrace(); 
        } 
    } 
 
    @Override 
    public void close() 
    { 
        super.close(); 
        helloDao = null; 
    } 
 
    public Dao<Hello, Integer> getHelloDataDao() throws SQLException 
    { 
        if (helloDao == null) 
        { 
            helloDao = getDao(Hello.class); 
        } 
        return helloDao; 
    } 
} 

package com.cng; 
 
import java.sql.SQLException; 
import java.util.List; 
 
import com.cng.modal.Hello; 
import com.cng.utils.DataHelper; 
import com.j256.ormlite.android.apptools.OrmLiteBaseActivity; 
import com.j256.ormlite.dao.Dao; 
 
import android.os.Bundle; 
import android.widget.TextView; 
 
 
 
 
public class OrmliteLoginActivity extends OrmLiteBaseActivity<DataHelper> 
{ 
    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
        TextView tv = (TextView) this.findViewById(R.id.output); 
        try 
        { 
            Dao<Hello, Integer> helloDao = getHelper().getHelloDataDao(); 
            // 添加數據 
            for (int i = 0; i < 2; i++) 
            { 
                Hello hello = new Hello("Hello" + i); 
                helloDao.create(hello); 
            } 
            tv.setText(tv.getText() + "\n" + "添加數據完成"); 
            // 查詢添加的數據 
            List<Hello> hellos = helloDao.queryForAll(); 
            for (Hello h : hellos) 
            { 
                tv.setText(tv.getText() + "\n" + h.toString()); 
            } 
//           刪除數據第一條數據 
            helloDao.delete(hellos.get(0)); 
            tv.setText(tv.getText() + "\n" + "刪除數據完成"); 
            // 重新查詢數據 
            hellos = helloDao.queryForAll(); 
            for (Hello h : hellos) 
            { 
                tv.setText(tv.getText() + "\n" + h.toString()); 
            } 
            // 修改數據 
            Hello h1 = hellos.get(0); 
            h1.setWord("這是修改過的數據"); 
            tv.setText(tv.getText() + "\n" + "修改數據完成"); 
            helloDao.update(h1); 
            // 重新查詢數據 
            hellos = helloDao.queryForAll(); 
            for (Hello h : hellos) 
            { 
                tv.setText(tv.getText() + "\n" + h.toString()); 
            } 
 
        } catch (SQLException e) 
        { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
 
    } 
} 
  package com.cng.modal; 
 
import android.R.integer; 
 
import com.j256.ormlite.field.DatabaseField; 
 
public class Hello 
{ 
    @DatabaseField(generatedId = true,unique=true) 
    int id; 
    @DatabaseField 
    String word; 
    //這是必須加的，否則會出錯 
    public Hello(){} 
    public int getId() 
    { 
        return id; 
    } 
    public Hello(String word) 
    { 
        super(); 
        this.word = word; 
    } 
    public void setId(int id) 
    { 
        this.id = id; 
    } 
 
    public String getWord() 
    { 
        return word; 
    } 
 
    public void setWord(String word) 
    { 
        this.word = word; 
    } 
 
    @Override 
    public String toString() 
    { 
        StringBuilder sb = new StringBuilder(); 
        sb.append("id=").append(id); 
        sb.append(" ,word=").append(word); 
        return sb.toString(); 
    } 
 www.2cto.com
} 

就這三個類，datahelper是操作數據庫的類，可新建，更新表，Hello是一個映射到數據庫表的類，具體的看api  文檔的下載地址是http://ormlite.com/releases/(其中的jar包也在這裡下載)   OrmliteLoginActivity就是activity類，它沒繼承activity，而是繼承了OrmLiteBaseActivity類。