[代码记录生活]无框架BaseDao的实现_JAVA_编程开发_程序员俱乐部

/* 纯为学习，无营养的评论，请绕道，谢谢 */

  public interface BaseDao<T> { //采用泛型类
	public ArrayList<T> query(String sql,Object[] obj);
	public boolean update(String sql,Object[] obj);
  }

   public class DaoSupport<T> implements BaseDao<T> {
	private Connection con;
	private ResultSet rs;
	private PreparedStatement pstmt;
	private Class clazz = GenericUtils.getSuperGenericType(this.getClass()); //获得超类，参数化类型。

	public ArrayList<T> query(String sql, Object[] obj) {
		ArrayList<T> list = new ArrayList<T>();
		con = DBUtil.getConnection();
		try {
			pstmt = con.prepareStatement(sql);
			if (obj != null) {
				for (int i = 0; i < obj.length; i++) {
					pstmt.setObject(i + 1, obj[i]);
				}
			}
			rs = pstmt.executeQuery();

			list = mapping(rs);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		return list;
	}

	public ArrayList<T> mapping(ResultSet rs) {
		ArrayList<T> list = new ArrayList<T>();
		try {
			while (rs.next()) {
				Object obj = this.clazz.newInstance();

				Field[] fields = this.clazz.getDeclaredFields();
				for (int i = 0; i < fields.length; i++) {
					String fieldName = fields[i].getName();
					// setter
					String setMethodName = "set"
							+ fieldName.substring(0, 1).toUpperCase()
							+ fieldName.substring(1);
					// Method
					Method m = this.clazz.getDeclaredMethod(setMethodName,
							fields[i].getType());
					// 调用方法,防止类型不匹配，自写
					if (fields[i].getType().equals(int.class)) {
						m.invoke(obj, rs.getInt(fieldName));
					} else if (fields[i].getType().equals(Date.class)) {
						m.invoke(obj, rs.getDate(fieldName));
					} else {
						m.invoke(obj, rs.getObject(fieldName));
					}

				}

				list.add((T) obj);

			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		return list;
	}

	public boolean update(String sql, Object[] obj) {
		con = DBUtil.getConnection();
		try {
			pstmt = con.prepareStatement(sql);
			if (obj != null) {
				for (int i = 0; i < obj.length; i++) {
					pstmt.setObject(i + 1, obj[i]);
				}
			}

			if (pstmt.executeUpdate() > 0)
				return true;
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			DBUtil.closeAll(con, pstmt, null);
		}

		return false;
	}

}

  public class GenericUtils {

	public static Class getSuperGenericType(Class clazz){
		//超类是参数化类型
		Type type=clazz.getGenericSuperclass();
		
		//ParameterizedType 表示参数化类型，如 Collection<String>。 
		ParameterizedType paramType=(ParameterizedType)type;
		
		//返回表示此类型实际类型参数的 Type 对象的数组。 
		Type[] types=paramType.getActualTypeArguments();
		return (Class)types[0];
	}
  }

  public interface UserInfoDao extends BaseDao<UserInfo> {
	public boolean insertUser(UserInfo userInfo);

	public boolean updateUser(UserInfo userInfo);

	public boolean deleteUser(String uname);

	public ArrayList<UserInfo> getAllUsers();

	public UserInfo getUserByName(String uname);

  }

  public class UserInfoDaoImpl extends DaoSupport<UserInfo> implements UserInfoDao{	
	@Override
	public boolean deleteUser(String uname) {
		// TODO Auto-generated method stub
		String sql="delete from t_userinfo where uname=?";
		Object[] obj={uname};		
		return this.update(sql, obj);
	}

	@Override
	public ArrayList<UserInfo> getAllUsers() {
		// TODO Auto-generated method stub
		String sql="select * from t_userinfo ";
		return this.query(sql, null);
	}

	@Override
	public UserInfo getUserByName(String uname) {
		// TODO Auto-generated method stub
	  String sql="select * from t_userinfo where uname=?";
	  Object[] obj=new Object[]{uname};	  
	  ArrayList<UserInfo> list=this.query(sql, obj);
	  UserInfo bean=null;
	  if (list.size()>0) bean=list.get(0);	  
		return bean;
	}

	@Override
	public boolean insertUser(UserInfo userInfo) {
		// TODO Auto-generated method stub
		String sql="insert into t_userinfo values(?,?)";
		Object[] obj=new Object[]{userInfo.getUname(),userInfo.getUpwd()};
		return this.update(sql, obj);
	}

	@Override
	public boolean updateUser(UserInfo userInfo) {
		// TODO Auto-generated method stub
		String sql="update t_userInfo set upwd=? where uname=?";
		Object[] obj=new Object[]{userInfo.getUpwd(),userInfo.getUname()};
		return this.update(sql, obj);
	}

}