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android orm映射框架 ormlite (类似于hibernate) 很强大

程序员文章站 2022-07-15 12:45:39
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初学android不久,由于我是以前学过j2ee,什么ssh曾经用过,java的数据库持久化框架hibernate给程序操作数据库提供了方便,学习android的时候,想看看是否有个操作数据库的框架,谷歌了下,发现android的数据库框架很多什么,但都缺乏中文文档(本人还没过六级。。英语很差),几乎找不到例子,最后找到了ormlite,一个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();
	}

}

 

 

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。

 

ormlite还在学习中,表示这个android框架很强大>_<。