Android ORM框架介绍之greenDao封装(二)

我会带着你远行 2022-07-17 00:41 400阅读 0赞

## Android ORM框架介绍之greenDao封装(二) ##

数据库操作增删改查操作重复太高，所以需要进行抽取，通过DataBaseManager统一管理。

package www.weshared.greendao;
    
    import android.content.Context;
    import android.database.Cursor;
    import android.support.annotation.NonNull;
    import com.zhang.db.dao.DaoMaster;
    import com.zhang.db.dao.DaoSession;
    import com.zhang.db.entity.BaseModel;
    import com.zhang.db.entity.Model;
    import org.greenrobot.greendao.AbstractDao;
    import org.greenrobot.greendao.query.WhereCondition;
    import java.util.List;
    
    public class DataBaseManager<T> {
    
        protected static final String DB_NAME = "my.db";
        protected final DaoSession session;
        protected final AbstractDao dao;
    
        private static final String DB_NAME = "my.db";
        private DaoSession session;
        private AbstractDao dao;
        private DaoMaster.DevOpenHelper helper;
        private DaoMaster master;
    
        private static volatile DataBaseManager manager;
    
        private DataBaseManager(Context context) {
            if (helper == null) {
                helper = new DaoMaster.DevOpenHelper(context, DB_NAME);
            }
        }
    
        public static DataBaseManager getInstance(Context context) {
            if (manager == null) {
                synchronized (DataBaseManager.class) {
                    if (manager == null) {
                        manager = new DataBaseManager(context);
                    }
                }
            }
            return manager;
        }
    
        //未加密
        public DataBaseManager create(T t) {
            if (helper != null) {
                master = new DaoMaster(helper.getWritableDb());
            }
            session = master.newSession();
            dao = createDao(session, t.getClass());
            return manager;
        }
    
        //加密 [需要依赖 compile 'net.zetetic:android-database-sqlcipher:3.5.3']
        public DataBaseManager create(String pwd,T t) {
            if (helper != null) {
                master = new DaoMaster(helper.getEncryptedWritableDb(pwd));
            }
            session = master.newSession();
            dao = createDao(session, t.getClass());
            return manager;
        }
        //如果Model类太多，使用工厂模式
        public AbstractDao createDao(@NonNull DaoSession session, Class<?> clazz) {
            if (BaseModel.class.equals(clazz)) {
                return session.getBaseDao();
            } else if (Model.class.equals(clazz)) {
                return session.getModelDao();
            }
            return null;
        }
    
        public long insert(T t) {
            return session.insert(t);
        }
    
        public long insertOrReplace(T t) {
            return session.insertOrReplace(t);
        }
    
        @SuppressWarnings("unchecked")
        public void insertAll(List<T> list) {
            dao.insertInTx(list);
        }
    
        @SuppressWarnings("unchecked")
        public void insertOrReplaceAll(List<T> list) {
            dao.insertOrReplaceInTx(list);
        }
    
        public void update(T t) {
            session.update(t);
        }
    
        @SuppressWarnings("unchecked")
        public void updateAll(List<T> list) {
            dao.updateInTx(list);
        }
    
        public void delete(T t) {
            session.delete(t);
        }
    
        @SuppressWarnings("unchecked")
        public void deleteAll(List<T> list) {
            dao.deleteInTx(list);
        }
    
        public void deleteAll() {
            dao.deleteAll();
        }
    
        @SuppressWarnings("unchecked")
        public List<T> queryAll() {
            return dao.loadAll();
        }
    
        @SuppressWarnings("unchecked")
        public T query(long id) {
            return (T) dao.loadByRowId(id);
        }
    
        @SuppressWarnings("unchecked")
        public T query(Object key) {
            return (T) dao.load(key);
        }
    
        /** * 简单的条件查询 */
        @SuppressWarnings("unchecked")
        public List<T> query(String where, String... args) {
            return dao.queryRaw(where, args);
        }
    
        /** * 简单的条件查询 */
        @SuppressWarnings("unchecked")
        public List<T> queryBuild1(WhereCondition condition, WhereCondition... conditions) {
            return dao.queryBuilder().where(condition, conditions).build().list();
        }
    
        /** * 查询个数 */
        @SuppressWarnings("unchecked")
        public long queryBuild2(WhereCondition condition, WhereCondition... conditions) {
            return dao.queryBuilder().where(condition, conditions).buildCount().count();
        }
    
        /** * 获取Cursor */
        @SuppressWarnings("unchecked")
        public Cursor queryBuild3(WhereCondition condition, WhereCondition... conditions) {
            return dao.queryBuilder().where(condition, conditions).buildCursor().query();
        }
    
    }

*工厂模式抽取\[注：如果类太多，使用工厂方法模式\]*

public class DaoFactory {
    
        public static AbstractDao createDao(@NonNull DaoSession session, Class<?> clazz) {
            if (BaseModel.class.equals(clazz)) {
                return session.getBaseDao();
            } else if (Model.class.equals(clazz)) {
                return session.getModelDao();
            }
            return null;
        }
    }

#### 在MainActivity中的使用 ####

public class MainActivity extends AppCompatActivity implements View.OnClickListener { 
    
        private Button insert;
        private Button delete;
        private Button deleteall;
        private Button update;
        private Button query;
        private Button queryall;
        private Button querybuild;
        private TextView tv_query;
        private TextView tv_queryall;
        private TextView tv_querybuild;
        private DataBaseManager<Model> manager;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            init();
            initView();
            initListener();
        }
    
        private void init() {
            try {
                manager = new DataBaseManager<Model>(MainActivity.this, Model.class.newInstance());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        private void initView() {
            insert = (Button) findViewById(R.id.btn_insert);
            delete = (Button) findViewById(R.id.btn_delete);
            deleteall = (Button) findViewById(R.id.btn_deleteall);
            update = (Button) findViewById(R.id.btn_update);
            query = (Button) findViewById(R.id.btn_query);
            queryall = (Button) findViewById(R.id.btn_queryall);
            querybuild = (Button) findViewById(R.id.btn_querybuild);
    
            tv_query = (TextView) findViewById(R.id.tv_query);
            tv_queryall = (TextView) findViewById(R.id.tv_queryall);
            tv_querybuild = (TextView) findViewById(R.id.tv_querybuild);
        }
    
        private void initListener() {
            insert.setOnClickListener(this);
            delete.setOnClickListener(this);
            deleteall.setOnClickListener(this);
            update.setOnClickListener(this);
            query.setOnClickListener(this);
            queryall.setOnClickListener(this);
            querybuild.setOnClickListener(this);
        }
    
        @Override
        public void onClick(View view) {
            switch (view.getId()) {
                case R.id.btn_insert:
                    Model model = new Model();
                    model.setName("zhangsan");
                    model.setAge(32);
                    model.setCreateTime(System.currentTimeMillis());
                    manager.insert(model);
                    break;
                case R.id.btn_update:
                    Model model1 = new Model();
                    model1.setId((long) 1);
                    model1.setName("lisi");
                    model1.setAge(23);
                    model1.setCreateTime(System.currentTimeMillis());
                    manager.update(model1);
                    break;
                case R.id.btn_delete:
                    Model model2 = new Model();
                    model2.setId((long) 2);
                    manager.delete(model2);
                    break;
                case R.id.btn_deleteall:
                    manager.deleteAll();
                    break;
                case R.id.btn_query:
                    Model m = manager.query(1);
                    if (m!=null){
                        tv_query.setText("单条查询："+m.toString());
                    }else {
                        tv_query.setText("单条查询：没有查询到结果");
                    }
                    break;
                case R.id.btn_queryall:
                    List<Model> li = manager.queryAll();
                    tv_queryall.setText("查询全部："+li.toString());
                    break;
                case R.id.btn_querybuild:
                    List<Model> list = manager.queryBuild1(ModelDao.Properties.Name.like("zhangsan"));//注意条件查询
                    tv_querybuild.setText("条件查询："+list.toString());
                    break;
            }
        }
    }

![image][]

*水平有限，封装的不是很好*

[image]: /images/20220717/f210d82bb5cf4f5db863965e8b2c08e6.png