安卓数据库封装

不妥之处希望给予纠正，学习中

首先写一个数据库的增删改查的抽象类，五个抽象方法，我只使用了一个User表，所以只有一个获取User表的方法，代码如下

package com.example.a21150.projectutils;

import android.content.Context;

import java.sql.SQLException;
import java.util.List;

/**
 * Created by 21150 on 2016/11/8.
 */
public abstract class DataBaseUtils<T> {

    private static DataBaseUtils mUserDataBaseUtils;

    public abstract void insert(T clzz) throws SQLException;

    public abstract void insert(List<T> list) throws SQLException;

    public abstract void delete(T clzz) throws SQLException;

    public abstract void update(T clzz) throws SQLException;

    public abstract List<T> queryForAll() throws SQLException;

    public abstract List<T> query(T clzz) throws SQLException;

    /**
     * 获取user表的Dao
     * @param context
     * @return
     */
    public static DataBaseUtils getUserDabaUtils(Context context) {

        if (mUserDataBaseUtils == null) {
            synchronized (DataBaseUtils.class) {
                mUserDataBaseUtils = UserDao.getDao(context);
            }
        }
        return mUserDataBaseUtils;
    }
}

下面是User表的Dao类，继承DataBaseUtils类，实现抽象方法，代码如下

package com.example.a21150.projectutils;

import android.content.Context;

import com.j256.ormlite.dao.Dao;

import java.sql.SQLException;
import java.util.List;

/**
 * Created by 21150 on 2016/11/8.
 */
public class UserDao extends DataBaseUtils<User> {

    //User表dao
    private Dao<User,Integer> mUserDao;

    private static UserDao mOrmLiteDataBase;

    private UserDao(Context context){
        try {
            mUserDao = (Dao<User, Integer>) OrmLiteHelper.getInstance(context).getDao(User.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static UserDao getDao(Context context){

        if (mOrmLiteDataBase == null){
            synchronized (UserDao.class){
                mOrmLiteDataBase = new UserDao(context);
            }
        }
        return mOrmLiteDataBase;
    }

    @Override
    public void insert(User clzz) throws SQLException {
        mUserDao.create(clzz);
    }

    @Override
    public void insert(List<User> list) throws SQLException {
        mUserDao.create(list);
    }

    @Override
    public void delete(User clzz) throws SQLException {
        mUserDao.delete(clzz);
    }

    @Override
    public void update(User clzz) throws SQLException {
            mUserDao.update(clzz);
    }

    @Override
    public List<User> queryForAll() throws SQLException {
        return mUserDao.queryForAll();
    }

    @Override
    public List<User> query(User clzz) throws SQLException {
        List<User> name = mUserDao.queryBuilder().where().eq("name", clzz.getName()).query();
        return name;
    }
}

下面时数据库的框架类，我这里用的是ormlite,android studio 导包

compile 'com.j256.ormlite:ormlite-android:5.0'

代码如下

package com.example.a21150.projectutils;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
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 java.sql.SQLException;

/**
 * Created by 21150 on 2016/11/7.
 */
public class OrmLiteHelper extends OrmLiteSqliteOpenHelper{

    private static String dataBaseName = "mydata.db";
    private static int version = 1;

    private Dao<User,Integer> mUserDao;

    private static OrmLiteHelper mOrmLiteHelper;

    public OrmLiteHelper(Context context) {
        super(context, dataBaseName, null, version);
    }

    /**
     * 创建数据库，每次初始化的时候调用
     * @param database
     * @param connectionSource
     */
    @Override
    public void onCreate(SQLiteDatabase database, ConnectionSource connectionSource) {

        try {
            TableUtils.createTable(connectionSource,User.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 更新数据库
     * @param database  原生SQLiteDatabase,可以执行sql语句
     * @param connectionSource 链接数据库资源
     * @param oldVersion 旧版本号
     * @param newVersion 新版本号
     */
    @Override
    public void onUpgrade(SQLiteDatabase database, ConnectionSource connectionSource, int oldVersion, int newVersion) {
        try {
            TableUtils.dropTable(connectionSource,User.class,true);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 单例获取数据库
     * @param context
     * @return
     */
    public static synchronized OrmLiteHelper  getInstance(Context context){
        if(mOrmLiteHelper == null){
            synchronized (OrmLiteHelper.class){
                mOrmLiteHelper = new OrmLiteHelper(context);
            }
        }
        return mOrmLiteHelper;
    }

    /**
     * 获取单例的dao
     * @return
     */
    private Dao<User,Integer> getUserDao(){
        if (mUserDao == null){
            synchronized (OrmLiteHelper.class){
                try {
                    mUserDao = mOrmLiteHelper.getDao(User.class);
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        return mUserDao;
    }
}

在activity中使用

package com.example.a21150.projectutils;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import java.sql.SQLException;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private DataBaseUtils<User> mDataBaseUtils;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mDataBaseUtils = DataBaseUtils.getUserDabaUtils(this);

        try {
            List<User> song = mDataBaseUtils.query(new User("dddd", 15));
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

User类如下

package com.example.a21150.projectutils;

import com.j256.ormlite.field.DatabaseField;
import com.j256.ormlite.table.DatabaseTable;

/**
 * Created by 21150 on 2016/11/7.
 */

@DatabaseTable(tableName = "user")
public class User {
    @DatabaseField(columnName = "id", generatedId = true)
    private int id;
    @DatabaseField(columnName = "name")
    private String name;
    @DatabaseField(columnName = "age")
    private int age;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public User(){}
}

加入更换数据库框架时。只需要更改更改DataBaseUtils的实现类即可