android orm映射框架（类似hibernate）基本使用

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转载自 http://www.2cto.com/kf/201208/150354.html

android orm映射框架，可像hibernate一样操作数据库。以下代码是我从网上摘录下来的，仅供参考.

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(), "创建数据库失败", 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(), "更新数据库失败", 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();
            // 添加数据
            for (int i = 0; i < 2; i++)
            {
                Hello hello = new Hello("Hello" + i);
                helloDao.create(hello);
            }
            tv.setText(tv.getText() + "\n" + "添加数据完成");
            // 查询添加的数据
            List<Hello> hellos = helloDao.queryForAll();
            for (Hello h : hellos)
            {
                tv.setText(tv.getText() + "\n" + h.toString());
            }
//           删除数据第一条数据
            helloDao.delete(hellos.get(0));
            tv.setText(tv.getText() + "\n" + "删除数据完成");
            // 重新查询数据
            hellos = helloDao.queryForAll();
            for (Hello h : hellos)
            {
                tv.setText(tv.getText() + "\n" + h.toString());
            }
            // 修改数据
            Hello h1 = hellos.get(0);
            h1.setWord("这是修改过的数据");
            tv.setText(tv.getText() + "\n" + "修改数据完成");
            helloDao.update(h1);
            // 重新查询数据
            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;
    //这是必须加的，否则会出错
    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();
    }
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}

就这三个类，datahelper是操作数据库的类，可新建，更新表，Hello是一个映射到数据库表的类，具体的看api 文档的下载地址是http://ormlite.com/releases/(其中的jar包也在这里下载) OrmliteLoginActivity就是activity类，它没继承activity，而是继承了OrmLiteBaseActivity类。