Android - OrmLite 实现仿Web那样写Dao

本文转自OSCHINA

写了一个demo,这个实例,只针对单一的实体bean,日后在补充其他示例

实体bean

BaseColumn.java

package org.mo.ormlite.entity;
 
import com.j256.ormlite.field.DatabaseField;
 
import java.io.Serializable;
 
/**
 * Created by moziqi on 2015/1/18 0018.
 */
public abstract class BaseColumn implements Serializable {
    @DatabaseField(generatedId = true, columnName = "_id")
    private Long id;
    @DatabaseField(columnName = "create_date")
    private String createDate;
    @DatabaseField(columnName = "update_date")
    private String updateDate;
    //getset自己补充
}

　　

User.java

package org.mo.ormlite.entity;
 
import com.j256.ormlite.field.DatabaseField;
import com.j256.ormlite.table.DatabaseTable;
 
import java.io.Serializable;
import java.util.List;
 
/**
 * Created by moziqi on 2015/1/18 0018.
 */
@DatabaseTable(tableName = "tb_user")
public class User extends BaseColumn {
    @DatabaseField(index = true, columnName = "username")
    private String username;
    @DatabaseField(canBeNull = false, columnName = "password")
    private String password;
    @DatabaseField(columnName = "login_time")
    private String loginTime;
 
    //getset自己补充
     
    @Override
    public String toString() {
        final StringBuffer sb = new StringBuffer("User{");
        sb.append("username='").append(username).append('\'');
        sb.append(", password='").append(password).append('\'');
        sb.append(", loginTime='").append(loginTime).append('\'');
        sb.append('}');
        return sb.toString();
    }
}

　　

Dao操作

DatabaseHelper.java

package org.mo.ormlite.dao;
 
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
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 org.mo.ormlite.entity.User;
import org.mo.util.MyConstant;
 
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
 
/**
 * Created by moziqi on 2015/1/18 0018.
 */
public class DatabaseHelper extends OrmLiteSqliteOpenHelper {
 
    private final static String TAG = DatabaseHelper.class.getSimpleName();
 
    private Dao<User, Long> userDao = null;
 
    private Map<String, Dao> daos = new HashMap<String, Dao>();
 
    private static DatabaseHelper instance;
 
    public DatabaseHelper(Context context) {
        super(context, MyConstant.MyDB.DATABASE_NAME, null, MyConstant.MyDB.DATABASE_VERSION);
    }
 
    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase, ConnectionSource connectionSource) {
        try {
            TableUtils.createTable(connectionSource, User.class);
        } catch (SQLException e) {
            Log.e(TAG, e.getMessage());
        }
    }
 
    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, ConnectionSource connectionSource, int i, int i2) {
        try {
            TableUtils.dropTable(connectionSource, User.class, true);
            onCreate(sqLiteDatabase, connectionSource);
        } catch (SQLException e) {
            Log.e(TAG, e.getMessage());
        }
    }
 
    public Dao<User, Long> getUserDao() throws SQLException {
        if (userDao == null) {
            userDao = getDao(User.class);
        }
        return userDao;
    }
 
 
    /**
     * 单例获取该Helper
     *
     * @param context
     * @return
     */
    public static synchronized DatabaseHelper getHelper(Context context) {
        context = context.getApplicationContext();
        if (instance == null) {
            synchronized (DatabaseHelper.class) {
                if (instance == null)
                    instance = new DatabaseHelper(context);
            }
        }
        return instance;
    }
 
    public synchronized Dao getDao(Class clazz) throws SQLException {
        Dao dao = null;
        String className = clazz.getSimpleName();
 
        if (daos.containsKey(className)) {
            dao = daos.get(className);
        }
        if (dao == null) {
            dao = super.getDao(clazz);
            daos.put(className, dao);
        }
        return dao;
    }
 
    /**
     * 释放资源
     */
    @Override
    public void close() {
        super.close();
        for (String key : daos.keySet()) {
            Dao dao = daos.get(key);
            dao = null;
        }
    }
}

　　

UserDao.java

package org.mo.ormlite.dao;
 
import android.content.Context;
import com.j256.ormlite.dao.Dao;
import org.mo.ormlite.entity.User;
 
import java.sql.SQLException;
import java.util.List;
 
/**
 * Created by moziqi on 2015/1/18 0018.
 */
public class UserDao implements BaseDao<User> {
    private Context mContext;
    private Dao<User, Long> mUserLongDao;
    private DatabaseHelper mDatabaseHelper;
 
    public UserDao(Context mContext) {
        this.mContext = mContext;
        try {
            this.mDatabaseHelper = DatabaseHelper.getHelper(mContext);
            this.mUserLongDao = mDatabaseHelper.getDao(User.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
 
    /**
     * 不存在,返回false
     *
     * @param username
     * @return
     */
    public boolean findByUsername(String username) {
        boolean flag = false;
        try {
            List<User> users = mUserLongDao.queryForEq("username", username);
            if (users.size() > 0) {
                flag = true;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return flag;
    }
 
    @Override
    public boolean save(final User entity) {
        boolean flag = false;
        try {
            int result = mUserLongDao.create(entity);
            if (result > 0) {
                flag = true;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return flag;
    }
 
    @Override
    public boolean update(final User entity) {
        boolean flag = false;
        try {
            int result = mUserLongDao.update(entity);
            if (result > 0) {
                flag = true;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return flag;
    }
 
    @Override
    public boolean delete(final User entity) {
        boolean flag = false;
        try {
            int result = mUserLongDao.delete(entity);
            if (result > 0) {
                flag = true;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return flag;
 
    }
 
    @Override
    public List<User> findAll() {
        List<User> users = null;
        try {
            users = mUserLongDao.queryForAll();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return users;
    }
 
    @Override
    public User findOneById(final long id) {
        User user = null;
        try {
            user = mUserLongDao.queryForId(id);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return user;
    }
 
    @Override
    public long countAll() {
        long count = 0;
        try {
            count = mUserLongDao.countOf();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return count;
    }
 
    /**
     * 拼接查询,分页查询
     *
     * @param offset
     * @param limit
     * @return
     */
    @Override
    public List<User> findAllByLimit(final long offset, final long limit) {
        List<User> query = null;
        try {
            query = mUserLongDao.queryBuilder().
                    orderBy("create_date", false).
                    offset(offset).
                    limit(limit).
                    query();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return query;
    }
}

　　

service层

UserService.java

package org.mo.ormlite.service;
 
import android.content.Context;
import android.widget.Toast;
import com.j256.ormlite.android.AndroidDatabaseConnection;
import com.j256.ormlite.support.DatabaseConnection;
import org.mo.ormlite.R;
import org.mo.ormlite.dao.DatabaseHelper;
import org.mo.ormlite.dao.UserDao;
import org.mo.ormlite.entity.User;
 
import java.sql.SQLException;
import java.sql.Savepoint;
import java.util.List;
 
/**
 * Created by moziqi on 2015/1/18 0018.
 */
public class UserService {
    // 添加事物
    public DatabaseConnection connection;
    private UserDao mUserDao;
    private Context mContext;
 
    public UserService(Context mContext) {
        this.mContext = mContext;
        mUserDao = new UserDao(mContext);
        connection = new AndroidDatabaseConnection(
                DatabaseHelper.getHelper(mContext).getWritableDatabase(), true);
    }
 
    /**
     * 参考这个,其他加事务吧
     *
     * @param user
     * @return
     */
    public int saveUser(User user) {
        int flag = -1;//保存失败
        Savepoint savepoint = null;
        try {
            boolean byUsername = mUserDao.findByUsername(user.getUsername());
            if (byUsername) {
                flag = 0;//用户名存在
            } else {
                savepoint = connection.setSavePoint("save");
                if (mUserDao.save(user)) {
                    flag = 1;//保存成功
                    connection.commit(savepoint);
                }
            }
        } catch (SQLException e) {
            try {
                e.printStackTrace();
                connection.rollback(savepoint);
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
        }
        return flag;
    }
 
    public boolean updateUser(User user) {
        return mUserDao.update(user);
    }
 
    public boolean deleteUser(User user) {
        return mUserDao.delete(user);
    }
 
    public User getUserById(long id) {
        return mUserDao.findOneById(id);
    }
 
    public List<User> getAll() {
        List<User> users = mUserDao.findAll();
        return users;
    }
 
    public long countAll() {
        return mUserDao.countAll();
    }
 
    public List<User> getAllByLimit(long currentPage, long size) {
        return mUserDao.findAllByLimit(currentPage - 1, size);
    }
}