ORMLite的使用

首先需要下载core和android两个jar

http://ormlite.com/releases/

然后拷贝到libs文件夹下并且添加为库

具体的使用看标程：

School.java

package com.turtle920.ormlitedemo;

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

@DatabaseTable(tableName = "school")
public class School {

    @DatabaseField(generatedId=true)
    private int id;

    @DatabaseField(columnName = "name")
    private String name;

    @DatabaseField
    private String location;

    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 String getLocation() {
        return location;
    }

    public void setLocation(String location) {
        this.location = location;
    }
}

以上通过注释符来用框架反射table和field，(generatedId=true)表示自增长

DBHelper.java

package com.turtle920.ormlitedemo;

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;

public class DBHelper extends OrmLiteSqliteOpenHelper {


    private final static int DATABASE_VERSION = 1;
    Dao<School, Integer> mSchoolDao;
    private static final String DB_NAME = "orm";
    private static DBHelper mDbHelper;

    private DBHelper(Context context) {
        super(context, DB_NAME, null, DATABASE_VERSION);
    }


    public static DBHelper getInstance(Context context) {
        if (mDbHelper == null) {
            mDbHelper = new DBHelper(context);
        }
        return mDbHelper;
    }

    @Override
    public void onCreate(SQLiteDatabase arg0, ConnectionSource arg1) {
        try {
            TableUtils.createTableIfNotExists(connectionSource, School.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }


    @Override
    public void onUpgrade(SQLiteDatabase arg0, ConnectionSource arg1, int arg2,
                          int arg3) {
    }

    public Dao<School, Integer> getSchoolDao() throws SQLException {
        if (mSchoolDao == null) {
            mSchoolDao = getDao(School.class);
        }
        return mSchoolDao;
    }


}

这个类继承自OrmLiteSqliteOpenHelper.class继承自SqliteOpenHelper.class，相当于是增强版的

MainActivity.java

package com.turtle920.ormlitedemo;

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

import com.j256.ormlite.dao.Dao;

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

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "DaoDaoDao";
    DBHelper mDbHelper;
    Dao<School, Integer> mSchoolDao;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mDbHelper = DBHelper.getInstance(this);
        try {
            mSchoolDao = mDbHelper.getSchoolDao();
        } catch (SQLException e) {
            Log.e(TAG, "constructor exception", e);
        }
        testDao();
    }

    private void testDao() {

        School school1 = new School();
        school1.setName("university");
        school1.setLocation("shanghai");

        School school2 = new School();
        school2.setName("middle school");
        school2.setLocation("hubei");

        School school3 = new School();
        school3.setName("CDQZ");
        school3.setLocation("CHENGDU");

        try {
            mSchoolDao.create(school1);
            mSchoolDao.create(school2);
            mSchoolDao.create(school3);
            //获取表中所有的student。
            Log.e(TAG,"************BEGIN*************");
            List<School> schools=mSchoolDao.queryForAll();
            Log.e(TAG, "before delete school1 size is:" + schools.size());
            for (int i = 0; i < schools.size(); i++) {
                Log.e(TAG, schools.get(i).getId()+" "+schools.get(i).getName()+" "+schools.get(i).getLocation());
            }
            mSchoolDao.delete(school1);

            //schools=mSchoolDao.queryForAll();
            schools=mSchoolDao.queryForEq("id","3");
            Log.e(TAG, "after delete school1 list size is:"+schools.size());
            for (int i = 0; i < schools.size(); i++) {
                Log.e(TAG, schools.get(i).getId()+" "+schools.get(i).getName()+" "+schools.get(i).getLocation());
            }

        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

}

其中一些操作：

.queryForEq("id","3");//查询“id”=“3”的
.queryForAll();//所有
.delete(school1);//删除
.deleteById(int id);//按id删
.update(school);//更新    
.create(school);//插入

可以看到对数据库的访问被投影成了对对象的操作，相比直接用android给的api操作数据库要短平快的多。