Android十八章：是时候在你项目用上greenDAO3GreenDao

dependencies {
    classpath 'com.android.tools.build:gradle:2.1.0'
    classpath 'org.greenrobot:greendao-gradle-plugin:3.1.0'

}

apply plugin: 'org.greenrobot.greendao'
android {
   greendao{
        schemaVersion 1                    //数据库 版本号
        targetGenDir 'src/main/java'    //生成DaoMaster类文件夹
        daoPackage   'com.ppjun.greendaotest.db'  //生成DaoMaster类包名
    }

}
dependencies {
    compile 'org.greenrobot:greendao:3.1.0'
}

@Entity
public class User {
    @Id
    private Long id;
    @Property(nameInDb = "username")
    private String userName;
    @Property(nameInDb = "password")
    private String passWord;
  
  
  //generate set和get方法 toString方法
  ...
}

public static final String DB_NAME = "ppjun.db";//数据库名称
DaoMaster.DevOpenHelper helper = new DaoMaster.DevOpenHelper(context, DB_NAME, null);//实例化一个DevOpenhelper,相当于sqlit的SQliteOpenHelper
DaoMaster daoMaster = new DaoMaster(helper.getWritableDb());//实例化DaoMaster
DaoSession daoSession = daoMaster.newSession();//实例化DaoSession
UserDao userDao =daoSession.getUserDao(); //获取UserDao实例来对表user进行操作


//add，这里的null 代表自增长的id，你还可以为user表插入unique的userid
        User user1 = new User(null, "ag1", "123456");
        User user2 = new User(null, "ag2", "123456");
        User user3 = new User(null, "ag3", "123456");
        userDao.insert(user1);
        userDao.insert(user2);
        userDao.insert(user3);

 //update，这里更新id是3的user的名字，id从1开始的，在where来添加匹配条件
        User user4 = userDao.queryBuilder().where(UserDao.Properties.Id.eq(3)).build().unique();
        user4.setUserName("kk");
        userDao.update(user4);

//delete，这里删除id是2的user
        List<User> userList2 = userDao.queryBuilder().where(UserDao.Properties.Id.eq(2)).build().list();
        for (User user5 : userList2)
            userDao.delete(user5);

  //query，重新user表全部user
        List<User> userList = userDao.queryBuilder().build().list();
        for (User user : userList)
            Log.i(TAG, user.toString());

public class User {
    @Id
    private Long id;
    @Property(nameInDb = "age")
    private int age;
  //generate getter and setter & toString
}

public class MyDBHelper extends DaoMaster.OpenHelper {
    public MyDBHelper(Context context) {
        super(context, DB_NAME,null);
    }

    @Override
    public void onUpgrade(Database db, int oldVersion, int newVersion) {
        super.onUpgrade(db, oldVersion, newVersion);
        NoteDao.createTable(db,true);
        db.execSQL("ALTER TABLE NOTE ADD COLUMN age");
    }


}

DBHelper dbHelper = new DBHelper(context);
DaoMaster daoMaster = new DaoMaster(dbHelper.getWritableDb());